Geo-Surface PowerZoner

Satellite NDVI-Based Management Zone Creation

Video Tutorials

Watch these step-by-step tutorial videos to learn how to use PowerZoner. The videos are organized in the recommended viewing order, from basic setup through advanced features.

1. Introduction to PowerZoner
2. Import Field Boundary & Fetch Satellite Data
3. Select Suitable Years for Composite Layer
4. Standard CPI-Based Zone Creation
5. Create Topo-Refined Low Productivity Zones
6. Import Shapefile Elevation (No LiDAR Areas)
7. Export Zones as Shapefile
8. Soil Sampling Tool Demo
9. Prescription Creation Tool Demo

Overview

PowerZoner is the most advanced satellite-based management zone creation tool available today. It analyzes multi-year crop performance patterns using NDVI (Normalized Difference Vegetation Index) data from Copernicus Sentinel-2 satellites, with unique features including peak seasonal NDVI per pixel (capturing maximum crop vigor during the growing season) and optional topography-based zone refinement to identify moisture-limited areas.

What is NDVI?
NDVI measures plant health and vigor using satellite imagery. Healthy, dense vegetation reflects more near-infrared light and less visible red light, resulting in higher NDVI values (-1 to +1 scale, where higher values indicate healthier vegetation). By analyzing NDVI patterns across multiple years, PowerZoner identifies consistent productivity zones in your fields.
What is CPI (Crop Productivity Index)?
PowerZoner converts raw NDVI data (-1 to +1 scale) into CPI (Crop Productivity Index) during composite creation. Each year's NDVI is normalized around its mean and set to 100, then years are averaged together. The resulting CPI values are mean-centered around 100, where values above 100 indicate areas of consistently higher-than-average crop productivity, and values below 100 indicate lower-than-average productivity. Each management zone is defined by its CPI range, allowing you to apply variable rate inputs based on actual historical crop performance.

Typical Workflow

  1. Setup Tab: Define field boundary, fetch satellite NDVI data (2015-present), and preview & select years for composite
  2. Zone Tab: Adjust zone parameters and compute management zones (automatically creates multi-year composite and classifies into zones)
  3. Topo Tab (Optional): Split low-productivity zones by wetness to identify moisture-limited areas (unique feature combining satellite + topography)
  4. Export Tab: Download shapefiles with CPI values for variable rate applications

About & Limitations

Important Disclaimer

PowerZoner is a data visualization and zone delineation tool only. It processes satellite NDVI data and topographic information "as-is" to create management zone maps based on historical crop performance patterns. PowerZoner does not provide agronomic advice, recommendations, or guarantees about crop production outcomes.

PowerZoner is NOT a replacement for professional agronomic consultation. Zone maps should be interpreted by qualified agronomists, crop consultants, or agricultural professionals who understand local soil conditions, crop requirements, and management practices. Always consult with agronomic experts before making management decisions based on PowerZoner zones.

Data Quality & Zone Reliability

PowerZoner will create zones for ANY field, regardless of whether that field has significant productivity variability. The software cannot determine if observed NDVI patterns represent meaningful agronomic differences or random noise. Users must evaluate whether their field has sufficient variability to justify zone-based management.
Data Selection Impacts Zone Quality

The quality of your zones depends entirely on the quality of years you select:
  • Including problematic years (split crops, mechanical failures, extreme weather events) will create zones that reflect those specific conditions, not typical field performance
  • Selecting too few years (1-2 years) may capture single-year anomalies rather than persistent patterns
  • Using years with suspect data (cloud contamination, crop rotation, significant management changes) will produce unreliable zones

Always preview years individually and exclude any that show anomalous patterns. Zones are only as reliable as the data you provide.

Boundary Accuracy is Critical

NDVI Cannot Distinguish Crop from Other Vegetation

PowerZoner analyzes all vegetation within your boundary, not just crops. Satellite imagery accurately measures vegetation health and density, but it cannot distinguish between crops and other vegetation types. Non-cultivated areas with dense vegetation will appear as "high productivity" zones even though they produce no crop yield.


Exclude These Non-Cultivated Areas from Your Boundary:
  • Wetlands and Sloughs: Dense cattails, reeds, and marsh vegetation will register as very high NDVI (falsely appearing as top-performing crop areas)
  • Bush and Shelterbelts: Trees and shrubs have high NDVI throughout the growing season and will distort zone boundaries
  • Grassed Waterways: Permanent grass cover appears as moderate-to-high NDVI and does not represent crop performance
  • Fence Rows and Field Margins: Weeds, volunteer vegetation, and perennial plants along edges will skew productivity analysis
  • Abandoned or Fallow Areas: Unmanaged vegetation creates false "high productivity" signals

Best Practice: Draw your boundary to include ONLY the actively cultivated crop area. If your field has internal wetlands, sloughs, or bush patches, either exclude them when drawing the boundary or manually edit the boundary shapefile to create "donut holes" (interior exclusion zones). Remember: the satellite imagery doesn't lie—it accurately shows vegetation—but it also doesn't know what is crop and what is other vegetation.

Topographic Wetness Limitations

The Refined Zones feature uses topographic wetness analysis to identify moisture-limited areas. This analysis has inherent limitations:

Best Practice: Use PowerZoner zones as a starting point for field investigation, not as definitive management boundaries. Ground-truth zones with soil sampling, yield data, field observations, and professional agronomic assessment before implementing variable rate strategies.

Licensing & Usage Terms

Copyright & Ownership

PowerZoner is a copyrighted product developed by Simon Knutson and is exclusively available via GIS4AG (gis4ag.com).

Owned and provided exclusively by:
17449275 Canada Inc.
Box 599
St. Claude, MB R0G 1Z0
Canada

License Structure & Commercial Use

Commercial use of PowerZoner is permitted and encouraged. PowerZoner is designed for professional agronomists, crop consultants, precision agriculture specialists, and farming operations. The following licensing structure ensures fair use while supporting professional consulting services.

Individual Users & Small Operations

Each user or business unit requires their own license and unique login credentials. Small operations operating from a single location may share one license among staff working as a cohesive unit.

Partnerships, Consulting Teams & Multi-User Businesses

Each agronomist, crop consultant, or professional who independently manages their own client portfolio requires their own individual license. Lead agronomists may share their license with their direct support staff (assistants, technicians, data managers), but a single license cannot be shared between multiple lead agronomists or consultants who each manage separate client relationships.

This ensures each professional has full access to PowerZoner's features for their client work, while allowing reasonable sharing with support team members who assist with data preparation and analysis.

License Compliance Examples

✓ Acceptable Use Cases:

  • One agronomist shares license with their assistant who prepares zone maps
  • Small 3-person consulting office operating from one location shares one license
  • Lead consultant shares access with GIS technician and field data collector
  • Individual farmer uses PowerZoner for their own operation and shares with farm manager

✗ Not Permitted:

  • Two independent agronomists in a partnership sharing one license
  • Regional consulting team with 4 lead agronomists sharing one license
  • Multi-location business with separate client portfolios per location using one license
  • Reselling or sublicensing PowerZoner access to other consultants or businesses

Output Sharing & Client Services

Zone maps, shapefiles, and analysis outputs created with PowerZoner may be freely shared with clients as part of professional consulting services. There are no restrictions on distributing PowerZoner-generated zone maps to your clients for use in their precision agriculture operations.

Prohibited Activities

Unauthorized reproduction, redistribution, or sublicensing of PowerZoner software is strictly prohibited.

  • Sharing login credentials with individuals who should have their own license
  • Reverse engineering, decompiling, or modifying the PowerZoner software
  • Circumventing authentication, usage tracking, or licensing controls
  • Creating derivative works based on PowerZoner's proprietary algorithms or code

Volume Licensing & Inquiries

For larger organizations, multi-user teams, or volume licensing inquiries, contact GIS4AG for customized pricing and license packages. Volume discounts are available for organizations with multiple agronomists or consulting teams.

Contact for Licensing:
gis4ag.com
Email: simon@gis4ag.com

Setup Tab: Boundary, Data Fetch & Year Selection

Step 1: Define Field Boundary

Three methods to define your field boundary:

1

Import Shapefile

Click Import Shapefile, select your boundary file, and it will be loaded automatically.

2

Draw Boundary

Click Draw Boundary, click points around your field perimeter, and double-click to finish.

3

Use Saved Project

If you have a saved PowerZoner project, boundaries are included in the project file.

Boundary Size Limit:
Maximum boundary size is 1500 acres. Boundaries larger than this will be rejected to protect API usage limits. If you need to analyze a larger area, please divide it into multiple fields of 1500 acres or less.
Load Field Boundary Shapefile
Load Field Boundary Shapefile

Step 2: Fetch NDVI Data

Once your boundary is loaded, click Fetch NDVI Data to retrieve Sentinel-2 satellite imagery for your field.

Data Details:
Source: Copernicus Sentinel-2 satellites (10m resolution)
Period: Peak growing season (June-August) for each year
Years Available: 2015-present
Metric: Maximum NDVI value during the season (captures peak crop vigor)
Processing: Cloud-masked, quality-filtered data
Tip: The system detects your UTM zone automatically to ensure accurate pixel alignment and area calculations.

Step 3: Preview & Select Years

After data fetch completes, you can preview and select which years to include in your multi-year composite. Click the eye icon next to any year to preview it on the map. Use the checkboxes to select which years to include in the composite.

What to Look For When Reviewing Year Previews:

✓ Good Years to Include:
• Consistent NDVI patterns across the field (smooth green-to-orange gradients)
• Similar spatial patterns between years
• Representative of typical crop performance

✗ Problematic Years to Exclude:
Split Crops: Two distinct shades of green indicating different crops/varieties planted in the same field
Mechanical Issues: Straight-line features of red, dark green, or light green (planter/sprayer skips, compaction tracks, tile blowouts)
Extreme Weather: Significantly different NDVI patterns from other years due to severe drought or excessive wetness
Crop Rotation: Lower overall NDVI if a different crop type was grown (e.g., soybeans vs. corn)
Crop Failure: Large areas of red or very low NDVI due to disease, pest damage, or germination failure
Best Practice: Compare 3-4 years side-by-side using the preview function. Exclude any years that look significantly different from the majority pattern. The goal is to identify persistent productivity zones, not single-year anomalies.

Selecting Years for Composite

Use the checkboxes next to each year to select which years to include in the multi-year composite. The composite combines NDVI data from your selected years to identify persistent productivity patterns, removing single-year variability caused by weather, pests, or management differences.

Best Practice: Include 3-5 years of data for reliable patterns. More years = more stable zones, but avoid years with known issues (severe drought, crop failure, different crops).

Rainfall Indicator

Each year displays a rainfall indicator icon showing May-July growing season precipitation relative to the 20-year average for that location. This helps you understand whether year-to-year NDVI differences are due to inherent soil/productivity patterns (persistent across years) or weather-driven variability (specific to wet/dry years).

Rainfall Categories:
Dry: Below average precipitation (bottom 33% of 20-year distribution)
Normal: Near-average precipitation (middle 33%)
Wet: Above average precipitation (top 33%)

Data Source: NOAA Climate Data (GHCN-Daily network)
Period: May-July growing season total precipitation
Baseline: 20-year rolling average centered on the year being classified

How to Use Rainfall Indicators

1. Understanding Year-to-Year Variability:
If a year shows significantly different NDVI patterns from other years, check its rainfall indicator:
  • Dry year + low overall NDVI: Drought stress - NDVI reflects water availability, not inherent soil quality
  • Wet year + low overall NDVI: Waterlogging/disease - excessive moisture reduced crop performance
  • Normal year: NDVI more accurately reflects inherent soil/drainage differences
2. Year Selection Strategy:
Recommended: Include 3-5 years with a mix of Normal and slightly Dry/Wet years to capture field variability under different moisture conditions.

Consider Excluding:
  • Extreme Dry Years: If NDVI patterns look dramatically different from other years (uniform low NDVI = drought stress masking soil differences)
  • Extreme Wet Years: If field shows widespread ponding or disease patterns not representative of typical years
  • Single Outlier Years: If one year stands out visually as inconsistent with the majority pattern (check rainfall indicator for confirmation)
Pro Tip: The goal is to identify persistent productivity patterns, not single-year weather effects. If you have 6 available years, select 3-4 Normal years plus 1 Dry and 1 Wet year to balance typical performance with moisture stress response. This creates zones that work across varying weather conditions.
Limitations: Rainfall indicators show growing season precipitation totals but don't capture timing (early vs late season rain), intensity (one heavy storm vs consistent moisture), or temperature effects (cool wet vs hot dry). Use as a general guide, not absolute predictor of crop performance.

Composite Method

Maximum Composite (automatic): PowerZoner uses maximum composite by default, which takes the highest NDVI value at each location across all selected years. This represents the field's maximum productivity potential and is least affected by temporary issues.

Why Maximum Composite?
Maximum NDVI shows where the field CAN perform well under good conditions. Areas that consistently show high NDVI have better soil, drainage, or topography. Areas that never achieve high NDVI may have fundamental limitations requiring different management.
Fetch & Preview Multi-Year Peak NDVI
Fetch & Preview Multi-Year Peak NDVI Data

Next Step: After selecting your years, proceed to the Zone Tab to create management zones from the composite data.

Zone Tab: Classification & Management

Convert the composite NDVI into discrete management zones with adjustable boundaries and statistics.

Zone Parameters

Number of Zones (2-10):
Choose how many management zones to create. Start with 3-5 zones for most fields. More zones = finer management but more complexity.
Classification Method:
Jenks Natural Breaks (recommended): Maximizes differences between zones - finds natural clustering in data
Equal Count (Quantiles): Equal acreage per zone - ensures balanced zone sizes
Equal Interval: Equal CPI range per zone - good for evenly distributed NDVI
Standard Deviation: Highlights statistical outliers - identifies extreme high/low areas
Min. Zone Blob Size (0.1-10 ac):
Controls the minimum size of each zone part (a "blob"). Individual zone blobs smaller than this threshold will be merged into surrounding zones. Helps eliminate small scattered patches and creates cleaner, more contiguous management zones.
Zone Smoothing (0-10):
Smoothing reduces smaller zone inclusions and blends subtle variability. Higher values create simpler, more uniform zones but may lose important field detail. Low values (0-2) are recommended to preserve productivity variation patterns in 10m satellite data.

Compute Management Zones

After selecting your years in the Setup Tab and adjusting zone parameters, click Compute Management Zones. This automatically creates the multi-year composite from your selected years and classifies it into management zones. Zones appear on the map with traffic-light colors (red = low CPI, yellow = medium, green = high).

Zone Statistics

After zones are created, statistics show for each zone:

Manual Break Adjustment

After creating zones, each zone row displays an interactive slider below the statistics that allows you to fine-tune the CPI boundary between that zone and the next higher zone. This powerful feature lets you override the automatic classification to match your field knowledge and management goals.

How It Works:
• Each slider controls the upper boundary (maximum CPI value) for that zone
• Drag the slider left to expand the zone (include more lower-CPI pixels)
• Drag the slider right to contract the zone (exclude lower-CPI pixels)
• The zone automatically reclassifies after 1 second (debounced live update)
• The slider's colored fill shows the current boundary position
• Constraints: You cannot move a slider below the previous zone's max or above the next zone's min
Pro Tip: Use manual adjustment when automatic classification creates a boundary that doesn't align with visible field patterns or your agronomic knowledge. For example, if you know a specific area has different soil but the same satellite signature, you can manually adjust the break to separate it. Use the toggle Toggle Zones button to compare zones with the underlying NDVI composite.
Important: Manual adjustments override the classification method. The status message will change to "Custom zone breaks applied" to indicate you're no longer using the standard Jenks/Quantile/StdDev classification.

Zone Merging (Advanced)

Simplify your management by combining similar zones. Click Merge Zones to enter merge mode.

1

Enter Merge Mode

Checkboxes appear next to each zone. Select 2 or more zones to merge.

2

Confirm Merge

Click "Merge Selected Zones". A dialog shows which zones will be merged and asks for confirmation.

3

Merged Result

Selected zones are combined into the lowest-numbered zone. All pixels are reassigned. Zone colors and statistics recalculate automatically.

4

Undo (10 seconds)

A success banner appears at the top with an Undo button. You have 10 seconds to undo the merge if you made a mistake.

When to Merge: Combine zones that have similar management needs even if their CPI values differ slightly. For example, merge Zone 1 and Zone 2 if both need the same fertilizer rate, or merge Zone 12 (Dry) and Zone 11 (Other) if wetness analysis shows no dry-area impact.
Merged zones are permanent after 10 seconds. Once the undo window expires, you cannot automatically restore the original zones. You would need to re-run zone classification.

Rename Zones

Customize zone IDs and add descriptive labels for shapefile export by clicking Rename Zones.

Zone ID: Change the numeric zone identifier (e.g., change Zone 1 → Zone 10). Must be unique across all zones. Only numeric values allowed.

Zone Description (optional): Add a text label up to 50 characters (e.g., "High Productivity Area", "Wet Depression - Needs Drainage"). This description appears in the shapefile's ZONE_LABEL attribute.
Use Case: Renumber zones to match your farm's existing numbering system, or add descriptions to help identify problem areas in your GIS software. For example, you might rename "Zone 13" to "Zone 5 - Needs Tile Drainage".
Duplicate IDs: If you assign the same ID to multiple zones, you'll get an error message and must correct it before saving. Each zone must have a unique numeric ID.

Click Save Changes to apply custom IDs/labels. Custom values will be used when exporting shapefiles. Click Reset to Default to restore original zone numbering.

Advanced Classification & Adjustment Controls
Advanced Classification & Adjustment Controls

Topo Tab: Wetness Analysis & Zone Refinement

The Topo Tab enhances your management zones by incorporating topographic wetness data to identify moisture-related limiting factors within low-productivity areas. This advanced analysis helps differentiate between areas limited by excess moisture (drainage issues) versus areas limited by insufficient moisture (dry hilltops, erosion), enabling more targeted management strategies.

Topography Data Fetching

Before performing wetness analysis, PowerZoner needs elevation data for your field. You can use one of two methods:

Method 1: Automatic LiDAR Fetch (Recommended)

  1. Select Region: Choose either US (3DEP data source) or Canada (HRDEM data source)
    CRITICAL: Select the correct region for your field location. Choosing the wrong data source will result in failed LiDAR fetch or invalid elevation data, preventing topographic wetness analysis. Always select the region that matches your field's geographic location.
  2. Fetch & Process LiDAR: Click to automatically:
    • Fetch high-resolution elevation data from public LiDAR sources
    • Upload elevation data to TauDEM server for terrain analysis
    • Calculate Topographic Wetness Index (TWI) using D∞ flow analysis
    • Download and display wetness layer on map
Note: The entire process (fetch → process → display) typically takes up to 1 minute. A full-screen spinner will block interactions until processing completes. Occasionally the LiDAR and/or NDVI APIs may be busy or experiencing issues - if the request fails, try again in a few minutes.

Method 2: Upload Elevation Point Shapefile

If you already have elevation data from field surveys or other sources, you can upload it directly:

  1. Prepare Your Shapefile:
    • Must be a point shapefile (not polygons or lines)
    • Must have an elevation column (field name must be elevation, z, elev, or height - case-insensitive)
    • Points should be distributed throughout your field for best accuracy
    • Recommended: Points collected at a minimum of 60ft swaths for reliable TWI calculation
    • Package as a ZIP file containing .shp, .shx, .dbf, and .prj files
  2. Upload: Click Upload Shapefile and select your ZIP file
  3. Processing: PowerZoner will:
    • Validate the shapefile format and elevation field
    • Interpolate your point data to create a continuous elevation surface
    • Upload to TauDEM server for terrain analysis
    • Calculate Topographic Wetness Index (TWI) using D∞ flow analysis
    • Download and display wetness layer on map
Elevation Shapefile Requirements:
• Must be point geometry (not polygons/lines)
• Must have elevation column (field name: elevation, z, elev, or height)
• Elevation values must be numeric (no text or null values)
• Points should cover the entire field area
• All files must be included: .shp, .shx, .dbf, .prj (zipped together)

Wetness-Productivity Correlation Analysis

After fetching topography data, use the Analyze Wetness-Productivity Correlation button to understand the relationship between topographic wetness and crop productivity in your field. This analysis reveals whether moisture patterns explain productivity differences, and recommends whether to use Standard or Refined zones.

Understanding the Scatter Plot

The correlation analysis displays an interactive scatter plot showing the relationship between wetness (X-axis) and crop productivity (Y-axis):

Scatter Plot Elements:
Green dots: Individual pixels from your field (each dot = 1 pixel location)
Red line: Best-fit trendline (linear or cubic model)
X-axis (Wetness Index): Topographic wetness values (0-99 scale, higher = wetter)
Y-axis (CPI): Crop Productivity Index (mean-centered around 100)
R² value: Goodness of fit (0.0 = no relationship, 1.0 = perfect relationship)

How It Works

PowerZoner compares each pixel's wetness index value (from topography) with its NDVI composite value (from satellite data), then fits two mathematical models:

The model with the highest R² is selected as the best fit and displayed as the red trendline.

Linear vs Cubic Models: What's the Difference?

When to Trust Each Model:

Linear Model Selected:
• Scatter plot shows a clear diagonal trend (upward or downward slope)
• Productivity increases OR decreases steadily as wetness increases
• Red trendline appears as a straight diagonal line
• Example: Wetter areas consistently have higher (or lower) productivity across entire wetness range

Cubic Model Selected:
• Scatter plot shows curved patterns (U-shapes, inverted-U, S-curves)
• Productivity relationship changes across wetness range (e.g., beneficial at low wetness, harmful at high wetness)
• Red trendline appears as a smooth curve with peaks or valleys
• Example: Moderate wetness = high CPI, but BOTH very dry AND very wet = low CPI
⚠️ Critical Insight: A low R² with a cubic model does NOT mean wetness is irrelevant! Even R² = 0.10-0.20 can indicate a meaningful curved pattern if the cubic model is significantly better than linear. Always look at the scatter plot visually - if you see a clear U-shape or inverted-U curve, wetness IS a limiting factor even if R² appears low.

Common Correlation Patterns

1. Inverted-U Pattern (Most Common)
What You'll See:
• Scatter plot forms an upside-down U shape
• Low wetness (dry areas): Low CPI
• Moderate wetness: High CPI (peak of curve)
• High wetness (wet areas): Low CPI drops again
• Cubic model selected with R² typically 0.10-0.30

What It Means:
BOTH dry AND wet areas have low productivity, but for opposite reasons:
  • Dry areas (low wetness): Water-limited productivity (hilltops, ridges, erosion)
  • Wet areas (high wetness): Drainage-limited productivity (depressions, poor drainage, compaction)
  • Moderate areas: Optimal moisture = highest productivity
Recommendation: Refined Zones - Split low-productivity areas into Low-Dry and Low-Wet zones for targeted management.
2. Wet-Only Impact Pattern
What You'll See:
• Scatter plot shows flat line at high CPI for low-to-moderate wetness
• Sharp CPI drop only at high wetness values (right side of plot)
• Cubic model selected with relatively low R² (0.10-0.25)

What It Means:
Only wet areas have productivity issues - dry areas perform just as well as moderate areas:
  • Low-to-moderate wetness: Consistent high productivity (no water limitation)
  • High wetness only: Strong CPI drop (drainage is the sole limiting factor)
Recommendation: Refined Zones + Merge Dry/Other - Create refined zones, then merge Low-Dry and Low-Other zones together (they both perform well). Keep Low-Wet separate for tile drainage targeting.
3. No Meaningful Pattern
What You'll See:
• Scatter plot looks like a random cloud of points
• No clear trend or curve visible
• Linear R² < 0.2 and cubic R² not much better
• Red trendline appears nearly flat

What It Means:
Topographic wetness does NOT explain productivity patterns in your field. Limiting factors are likely:
  • Soil texture or fertility differences (clay pockets, sandy areas)
  • Historical management patterns (manure application, past tillage)
  • Soil chemistry issues (pH, salinity, sodicity)
  • Subsurface features not visible in topography (compaction layers, hardpan)
Recommendation: Standard Zones - Use satellite-only zones. Topography won't add value for zoning in this field.

Automated Recommendation System

After analysis, PowerZoner provides a detailed automated recommendation with specific rationale based on your field's scatter plot pattern:

How to Use the Recommendation:
1. Read the scatter plot description - Understand which wetness-productivity pattern was detected
2. Review the rationale box - See why Standard or Refined zones are recommended
3. Visually confirm the pattern - Look at the scatter plot yourself to verify the automated detection
4. Follow the recommended workflow - Proceed with Standard or Refined zones as suggested

Note: The recommendation is based on statistical analysis and common patterns, but you can always override it. If you see clear wet/dry clusters in the scatter plot even with low R², Refined zones may still be valuable for your specific management goals.

Creating Refined Zones

If the correlation analysis recommends Refined Zones (or if you want to explore wet/dry patterns), click Create Refined Zones. This process:

  1. Identifies all pixels in the lowest productivity zone (Zone 1)
  2. Splits Zone 1 into three categories based on wetness percentiles:
    • Dry (Low-Dry): Wetness < 40th percentile
    • Other (Low-Other): Wetness between 40th and 60th percentile
    • Wet (Low-Wet): Wetness > 60th percentile
  3. Applies blob-based majority classification (50% threshold) to maintain spatial coherence
  4. Applies spatial smoothing and minimum zone size filtering
  5. Renumbers zones: Zone 11 (Other), Zone 12 (Dry), Zone 13 (Wet), Zone 2+ (original high-productivity zones)

Wetness Classification Thresholds

Fine-tune how low-productivity areas are classified into Dry, Wet, and Other zones by adjusting two percentile threshold sliders:

Dry Threshold (default: 40%):
Pixels with wetness values below this percentile are classified as Zone 12 (Low-Dry) - shown in brown. These are typically hilltops, ridges, or eroded areas with poor water retention.
Wet Threshold (default: 60%):
Pixels with wetness values above this percentile are classified as Zone 13 (Low-Wet) - shown in blue. These are typically depressions, poorly drained areas, or zones with ponding issues.
Other Zone (between thresholds):
Pixels with moderate wetness (between Dry and Wet thresholds) are classified as Zone 11 (Low-Other) - shown in red. These areas have low productivity for reasons OTHER than moisture (e.g., fertility, salinity, pH, compaction).
Two-Zone Mode: Set both sliders to the same value (e.g., both at 50%) to create only 2 zones: Dry (≤50%) and Wet (>50%), skipping the "Other" category entirely. The helper text below the sliders will confirm the mode.
Rule: The Wet threshold must be ≥ Dry threshold. If you set Wet below Dry, a warning message appears and the refined zones button is disabled.

Spatial Smoothing & Filtering

Refined zones can be spatially smoothed and filtered to remove noise and create cleaner management zones:

Refined Zone Numbering

Zone Numbers & Colors:
Zone 11 (Low-Other): Red - Low productivity, moderate wetness. Limiting factor likely non-moisture (fertility, pH, salinity, compaction)
Zone 12 (Low-Dry): Brown - Low productivity, dry areas. Limiting factor likely moisture deficiency (hilltops, erosion, poor water retention)
Zone 13 (Low-Wet): Blue - Low productivity, wet areas. Limiting factor likely excess moisture (poor drainage, compaction, waterlogging)
Zone 2, 3, 4, 5+: Orange → Green gradient - Standard productivity zones (Low-Medium to High)

Interpreting Refined Zones

Zone 12 (Low-Dry) - Brown

Areas with low productivity AND low wetness values. These areas typically:

What This Indicates: These characteristics suggest moisture deficiency is the primary limiting factor in Low-Dry zones. Consult with agronomists or drainage specialists to determine appropriate management strategies for your specific field conditions.

Zone 13 (Low-Wet) - Blue

Areas with low productivity AND high wetness values. These areas typically:

What This Indicates: These characteristics suggest excess moisture is the primary limiting factor in Low-Wet zones. Consult with drainage specialists or agronomists to determine appropriate management strategies for your specific field conditions.

Zone 11 (Low-Other) - Red

Areas with low productivity but moderate wetness values (neither consistently dry nor consistently wet). These areas typically:

Management Considerations: These areas require investigation beyond topography. Soil sampling (fertility, texture, pH, EC) or yield data analysis may help identify the limiting factor(s).

Standard vs Refined Zones: Decision Guide

Use Standard Zones When:

Use Refined Zones When:

Refined Zones Workflow

  1. Create Standard Zones in Zone Tab first
  2. Select Region (US or Canada) in Topo Tab
  3. Fetch & Process Topography (up to 1 minute)
  4. Analyze Wetness-Productivity Correlation to view relationship and recommendation
  5. Create Refined Zones if recommended or if you want to explore wet/dry patterns
  6. Review Zone Statistics to see acreage and NDVI for each zone type
  7. Export Shapefile in Export Tab (refined zones include zone type attributes)
Topo-Refined Low Productivity Zones
Topo-Refined Low Productivity Zones
Important: Refined zones are designed for consultants and agronomists who understand the limitations and context of topographic wetness analysis. PowerZoner provides the data visualization and zone delineation tools, but does not provide agronomic recommendations. Always consider soil sampling, yield data, field history, and on-site observations when developing management plans.

3D Terrain Viewer (BETA)

PowerZoner includes an advanced 3D terrain visualization tool powered by Cesium.js that displays your field's topography and management zones in immersive 3D. This feature is especially valuable for understanding how zones relate to terrain features like hills, valleys, and drainage patterns.

Accessing the 3D Viewer

After fetching elevation data (via LiDAR or uploaded shapefile), a 3D View button appears in the bottom-right corner of the screen. Click this button to launch the full-screen 3D terrain viewer.

Requirements: The 3D viewer requires elevation data to be loaded (either from automatic LiDAR fetch or uploaded elevation shapefile in Topo Tab). The button will be disabled until elevation data is available.

What You'll See

3D Visualization Components:
Terrain Mesh: High-resolution 3D surface showing actual field topography (hills, valleys, slopes)
Zone Overlay: Your management zones draped over the terrain as a semi-transparent color layer
Exaggerated Relief: Elevation differences are visually enhanced (vertical exaggeration) to make subtle terrain features visible
Interactive Navigation: Rotate, pan, and zoom to explore terrain from any angle
Color Scheme:
  • Standard Zones: Red (low productivity) → Yellow → Green (high productivity) traffic light scheme
  • Refined Zones: Zone 12 (Brown/Dry), Zone 13 (Blue/Wet), Zone 11 (Red/Other), Zone 2+ (Orange→Green gradient)

Navigation Controls

Mouse/Touchpad Controls:
Left-click + drag: Rotate the view around the field
Ctrl + hold left mouse: Rotate the view
Right-click + drag (or two-finger drag): Pan the view left/right/up/down
Scroll wheel (or pinch): Zoom in/out
Double-click: Reset to default view

On-Screen Buttons:
Close (X): Exit 3D viewer and return to 2D map
Reset View: Return camera to default overhead angle
Toggle Zones: Show/hide zone color overlay (terrain always visible)

Practical Uses

The 3D viewer helps you:

BETA Feature: The 3D viewer is in active development. Performance may vary depending on field size and device capabilities. For best experience, use a modern browser (Chrome, Edge, Firefox) with hardware acceleration enabled. Very large fields (>500 acres) may experience slower rendering.
Advanced 3D Terrain Viewer
Advanced 3D Terrain Viewer (BETA)

Export Tab: Shapefile & PDF

Export Shapefile

Click Export Shapefile to download your management zones as a shapefile ZIP.

Shapefile Attributes:
zone - Zone number (1, 2, 3, ...)
zone_name - Zone name ("Zone 1", "Zone 2", ...)
CPI_min - Minimum Crop Productivity Index
CPI_max - Maximum Crop Productivity Index
CPI_avg - Average CPI (midpoint)

Coordinate System: WGS84 (EPSG:4326)
Compatible with: QGIS, ArcGIS, SMS, Climate FieldView, John Deere Operations Center, precision ag equipment

Export Map to PDF

Click Export Map to PDF to create a printable map showing your zones with a legend and Copernicus data attribution.

Tip: The PDF includes the current map view with zones, so zoom and pan to your desired view before exporting.
Export Zones as Shapefile
Export Zones as Shapefile
Prescription Generator Tool
Prescription Generator Tool

Prescription Generator: Variable Rate Applications

The Prescription Generator creates variable rate application (VRA) prescriptions from your PowerZoner management zones. Export shapefiles with product-specific rate columns that work directly with precision agriculture equipment, farm management software, and application controllers.

What is a VRA Prescription?
A variable rate application prescription is a digital map that tells your equipment how much product (seed, fertilizer, lime, etc.) to apply in each zone of your field. PowerZoner generates prescriptions as shapefiles with rate columns for 1-6 different products, allowing you to manage multiple inputs simultaneously.

Accessing the Prescription Generator

Click the purple Rx button located at the bottom center of the map (next to the User Manual and Soil Sampling buttons) to open the Prescription Generator.

Two Operating Modes

Mode A: Use Current Zones

Automatically uses the zones currently loaded in PowerZoner. Works with both standard CPI-based zones and topo-refined zones (Dry-Limited/Wet-Limited classifications). The prescription inherits all zone attributes including CPI values and custom zone names.

Best for: Creating prescriptions immediately after generating zones, or when you want prescriptions to match exactly what you see on the map.

Mode B: Import Shapefile

Import a previously exported PowerZoner zone shapefile (from Export Tab) and add prescription rate columns to it. This allows you to create prescriptions later without re-generating zones, or to share zone shapefiles with clients who can then create their own prescriptions.

Best for: Creating prescriptions from saved zone files, working offline, or when consultants provide zone shapefiles to clients.

Creating a Prescription: Step-by-Step

1

Open Prescription Generator

Click the Rx button at bottom center of map. The tool automatically detects if you have zones loaded (Mode A) or prompts you to import (Mode B).

2

Enter Field Name

Type a field name (max 20 characters). This will be used in the export filename: {FieldName}_rx.zip

3

Select Number of Products

Choose how many products you want to prescribe (1-6). Common examples:

  • 1 product: Seed rate only
  • 2 products: Seed + nitrogen
  • 3 products: Seed + nitrogen + potash
  • 4+ products: Complete fertilizer blend + micronutrients

4

Configure Product Names & Rates

For each product:

  • Product Name: Enter a descriptive name (max 10 characters). Examples: "Seeds", "N_Rate", "P2O5", "Lime"
  • Unit: Specify the unit (max 8 characters). Examples: "seeds/ac", "lbs/ac", "kg/ha", "gal/ac"
  • Zone Rates: Enter the application rate for each zone. You'll see one input box per zone (Zone 1, Zone 2, etc.)

5

Export Prescription

Click Export Prescription. A shapefile ZIP will download: {FieldName}_rx.zip

Prescription Shapefile Attributes

Zone Information Columns:
zone_id - Zone number (1, 2, 3... or 11, 12, 13... for refined zones)
zone_name - Zone name (e.g., "Zone 1" or custom name if renamed)
zone_desc - Custom description (if you renamed zones)
CPI_min - Minimum CPI value in zone (historical productivity)
CPI_max - Maximum CPI value in zone
CPI_avg - Average CPI value in zone

Product Rate Columns:
• One column per product with sanitized name (e.g., "Seed_Rate", "N_Rate")
• Values are decimal rates rounded to 2 decimal places
• Example: If you enter "Seed Rate" as product name, column will be "Seed_Rate"
Coordinate System: WGS84 (EPSG:4326)
Geometry Type: MultiPolygon (dissolved by zone_id)
File Format: Shapefile (.shp, .shx, .dbf, .prj) in ZIP container

Using Prescriptions with Precision Ag Equipment

PowerZoner prescription shapefiles are compatible with most precision agriculture equipment and farm management software platforms, including:

Important: Consult your equipment or farm management software documentation for specific instructions on importing prescription shapefiles and mapping rate columns to application equipment. Each platform has different workflows for prescription import and activation.

Agronomic Consultation Required

PowerZoner provides zone delineation and prescription export tools ONLY.

PowerZoner does NOT provide rate recommendations or agronomic advice. Application rates must be determined by certified agronomists, crop consultants, or agricultural professionals based on soil tests, yield goals, crop requirements, and local conditions. Never apply rates without proper agronomic evaluation. Incorrect rates can reduce yield, waste inputs, cause environmental harm, or violate regulations.

Import Mode: Using Previous Zone Shapefiles

If you previously exported zones from PowerZoner (or received a zone shapefile from a consultant), you can create prescriptions without re-generating zones:

1

Open Prescription Generator

Click Rx button, then select "Import Shapefile" mode at the top of the popup.

2

Upload Zone Shapefile

Click the "Click to import shapefile" box or drag-and-drop your previously exported zone shapefile ZIP (e.g., Field1_zones.zip).

3

Verify Zone Detection

The tool automatically detects zone IDs from the shapefile (zone_id or zone field) and displays: "✓ Loaded 3 zones"

4

Configure & Export

Enter field name, select number of products, configure rates, and export. The prescription will include all original zone attributes plus your new rate columns.

Import Mode Benefits: Create prescriptions later when you have updated soil test results, share zone shapefiles with clients who create their own prescriptions, or work offline without PowerZoner access (just open the tool, import, and export).

Example: Creating a Two-Product Prescription

Technical Workflow Example

Scenario: Creating a prescription for 2 products across a 3-zone field

Step 1: Create zones in PowerZoner (Setup → Zone Tab → Compute Management Zones)

Step 2: Consult with your agronomist to determine appropriate application rates for each zone based on soil tests, yield goals, and crop requirements

Step 3: Open Prescription Generator (Rx button)

Step 4: Configure prescription:

  • Field Name: "Field_5_North"
  • Number of Products: 2
  • Product 1: Name = "Seeds", Unit = "seeds/ac"
  • Product 2: Name = "Nitrogen", Unit = "lbs/ac"
  • Enter rates for each zone (Zone 1, Zone 2, Zone 3) as determined by your agronomist

Step 5: Click "Export Prescription"

Result: Field_5_North_rx.zip with columns: zone_id, zone_name, CPI_min, CPI_max, CPI_avg, Seeds, Nitrogen

Common Issues & Solutions

Issue: Rx button is grayed out or doesn't work
Solution: The Rx button requires zones to be loaded. Make sure you've created zones (Zone Tab → Compute Management Zones) or switch to Import Mode to upload a zone shapefile.
Issue: Imported shapefile shows "0 zones detected"
Solution: The shapefile must have a zone_id or zone field with numeric zone numbers (1, 2, 3...). PowerZoner zone exports automatically include this field. If using a shapefile from another source, add a zone_id column in QGIS or ArcGIS before importing.
Issue: Equipment can't read prescription shapefile
Solution: Ensure your equipment supports shapefiles and WGS84 coordinate system. Some older equipment requires specific formats - consult your equipment manual or dealer. You may need to convert the shapefile to a different format (e.g., .isoxml for ISOBUS equipment) using your farm management software.

Advanced: Multi-Product Prescriptions

PowerZoner supports up to 6 products in a single prescription, enabling complete fertilizer programs:

Example: 6-Product Prescription Technical Capabilities
  • Product 1: Seeds (seeds/ac)
  • Product 2: Nitrogen (lbs/ac)
  • Product 3: Phosphate (lbs P2O5/ac)
  • Product 4: Potash (lbs K2O/ac)
  • Product 5: Lime (tons/ac)
  • Product 6: Zinc (lbs/ac)

The tool can handle any product type and unit. Consult with your agronomist to determine which products and rates are appropriate for your operation.

Understanding CPI Values

Crop Productivity Index (CPI) represents the NDVI-based productivity potential of each zone, normalized around a mean of 100.

How CPI Works:
PowerZoner creates a multi-year NDVI composite by normalizing each year around its mean productivity (100 = average for that year), then averaging across all selected years. This creates a relative productivity index where:

CPI = 100: Field average productivity
CPI > 100: Above-average productivity
CPI < 100: Below-average productivity
Interpreting CPI Values:
Above 100: Areas with consistently above-average crop vigor across multiple years. These zones typically have favorable soil conditions, topography, or drainage characteristics.

Around 100: Near-average productivity areas representing the field baseline.

Below 100: Zones with consistently below-average productivity. These areas may have limiting factors such as soil texture differences, drainage issues, topographic constraints, or nutrient deficiencies.
Important: CPI reflects historical multi-year crop performance patterns, not current crop conditions. CPI values represent relative productivity within your field and should be used for long-term zone-based management planning. Consult with agronomists to develop management strategies appropriate for your specific operation.

Tips & Best Practices

Data Selection

  • Include 3-5 years of data for stable, reliable zones
  • Exclude years with crop failures, different crops, or severe anomalies
  • Mix wet and dry years to see consistent patterns
  • Preview years before including them in the composite

Zone Creation

  • Start with 3-5 zones for most fields (70-200 acres)
  • Use "Quantiles" method for balanced zone sizes
  • Set minimum zone size to 1-2 acres to avoid unmanageable slivers
  • Apply 3-5 smoothing iterations for cleaner boundaries
  • Toggle zones on/off to verify they align with NDVI patterns

Zone Refinement

  • Adjust break sliders to align zones with field knowledge
  • Merge zones if they have similar management needs
  • Consider field access, equipment limitations, and operational efficiency
  • Compare with topography, soil maps, and yield data if available

Implementation

  • Export shapefiles with CPI attributes for variable rate maps
  • Import zones into farm management software or precision ag platforms
  • Create separate prescriptions for seeding, fertilizer, and other inputs
  • Track performance by zone to refine management over time
  • Re-run PowerZoner annually to update zones with new satellite data
Pro Tip: Save your PowerZoner project regularly so you can revisit and refine your zones as needed!

Map Tools

Click the ruler icon in the bottom-left corner to access measurement tools:

Measure Area: Draw a polygon to measure acreage (switchable units: acres, hectares, sq ft, sq m, sq km, sq mi)
Measure Distance: Draw a line to measure distances (switchable units: feet, meters, yards, miles, kilometers, inches)
Add Label: Click to place text annotations on the map
Clear Labels: Remove all annotations
Tip: Use measurement tools to verify field dimensions, check zone sizes, or annotate specific areas for reference.

GPS Geolocation

PowerZoner includes GPS tracking to help you navigate to specific areas of your field and verify zone boundaries on the ground. The geolocation button appears at the bottom-center of the map alongside other field tools.

Enabling GPS Tracking

Click the geolocation button to start tracking your position. Your browser will request permission to access your location.

Note: GPS tracking requires HTTPS (secure connection) or localhost. If using PowerZoner on a mobile device in the field, ensure you have a secure connection or cellular data enabled.

GPS Display

Location Marker: Red and white bullseye marker shows your current GPS position
Auto-Center: Map automatically centers on your location when first enabled
Active State: Button shows purple glow when tracking is active
High Accuracy: Uses high-precision GPS mode for field-level accuracy

Use Cases

  • Zone Verification: Navigate to low-productivity zones to investigate causes (compaction, drainage issues, soil differences)
  • Field Scouting: Track your position while walking through zones to collect observations
  • Ground Truthing: Verify that zone boundaries align with visible field features (soil color changes, drainage patterns, topography)
  • Mobile Navigation: Use on a tablet or smartphone while driving through the field to locate specific areas
  • Sampling Coordination: Combine with soil sampling tool to navigate to sample points
Tip: For best accuracy, enable GPS tracking outdoors with clear view of the sky. GPS accuracy may be reduced under tree cover, near buildings, or in valleys.

Soil Sampling Tool

The soil sampling tool provides a complete workflow for generating stratified soil sample points within your management zones, exporting them for GPS navigation, and tracking sampling progress in the field.

Opening the Sampling Tool

Click the soil sampling button at the bottom-center of the map. A full-screen sampling interface opens with a control sidebar and an embedded satellite imagery map.

Step 1: Select Zones

Choose how to load zones for sampling:

Use Current Zones: Uses zones already created in PowerZoner (standard or refined zones)
Import Zone Shapefile: Upload a previously exported PowerZoner zone file
Note: Zones must be loaded before generating sample points. The tool displays the number of zones and their IDs once loaded.

Step 2: Configure Sampling

Set the number of sample points you want in each zone:

  • Use the Points per Zone slider (1-20 points, default is 3)
  • Total points = (Points per zone) × (Number of zones)
  • Example: 3 points per zone × 4 zones = 12 total sample points
Recommendation: Use 3-5 points per zone for most fields. More points provide better spatial coverage but increase time and lab costs.

Step 3: Generate Points

Click Auto-Generate Points to create sample locations:

Random Placement: Points are randomly distributed within each zone boundary
Minimum Spacing: 100-meter spacing between points prevents clustering
Boundary Validation: Points guaranteed to fall within field boundary
Smart Retry: If random placement fails, falls back to zone centroid

Generated points appear on the map as numbered markers color-coded by zone. The sidebar displays a complete list with Point ID, Zone ID, and coordinates.

Step 4: Edit Point Locations

Adjust point positions as needed:

  • Drag Points: Click and drag any point marker to a new location on the map
  • Click to Zoom: Click a point in the sidebar list to zoom the map to that location
  • Delete Points: Remove individual points or clear all points to start over
Common Edits: Move points to avoid obstacles (rocks, trees, buildings), waterways, field access roads, or areas outside production zones.

Step 5: Export for Field Use

Save your sample points as KML files for GPS navigation:

Export Points (KML): Standard export for archiving and future reference
Export for GPS Device: Optimized format for Garmin, Trimble, and handheld GPS units

KML files include:

  • Point ID and zone assignment
  • GPS coordinates (latitude/longitude)
  • Visited status (unvisited or visited with timestamp)
  • Color-coded markers (red = unvisited, green = visited)
Compatible Devices: Works with Google Earth, Garmin GPS devices (eTrex, GPSMAP), Trimble units, smartphone GPS apps (Gaia GPS, Avenza Maps), and ArcGIS Field Maps.

Step 6: GPS Navigation in Field

Use GPS tracking to navigate to sample points:

  1. Import your KML file in the soil sampling tool (or use freshly generated points)
  2. Click Enable GPS Tracking
  3. Blue GPS marker appears showing your current location
  4. Sidebar displays distance to nearest unvisited point (updates in real-time)
  5. Navigate to point using distance indicator
  6. Collect soil sample at point location
  7. Check Visited box for that point (marker turns green, timestamp recorded)
  8. Repeat for all points
GPS Display:
• Current location: Latitude, Longitude
• Nearest unvisited: "Point 5 (Zone 2) - 127m"
• Updates every 5 seconds for battery efficiency
• High accuracy mode enabled

Import Existing Sample Points

Load previously created sample points:

  • Click Import Points (KML)
  • Select a KML file exported from PowerZoner or another source
  • Points are loaded onto the map and listed in the sidebar
  • Visited status and timestamps are preserved if previously recorded
Important: Imported points must include zone assignment information. KML files from non-PowerZoner sources may not work correctly.

Complete Workflow Example

Desktop Preparation:
1. Create zones in PowerZoner (4 zones)
2. Open soil sampling tool
3. Set "Points per zone: 3"
4. Generate 12 points
5. Drag Point 7 to avoid drainage ditch
6. Export KML: soil_samples_2025.kml

Field Collection:
7. Open PowerZoner on mobile device
8. Import soil_samples_2025.kml
9. Enable GPS tracking
10. Navigate to Point 1 (distance: 45m → 12m → arrived)
11. Collect sample, mark visited
12. Repeat for Points 2-12
13. Export updated KML with timestamps
14. Submit to soil lab with zone information

Best Practices

  • Stratified Sampling: PowerZoner automatically ensures points are distributed across all zones for representative sampling
  • Composite Samples: Collect 3-5 sub-samples within 10 feet of each point location and combine into one bag
  • Sampling Depth: Use consistent depth (typically 6-8 inches for cropland) at all points
  • Zone Attribution: Label sample bags with Point ID and Zone ID for zone-specific fertility recommendations
  • Weather Timing: Sample when soil moisture is consistent (avoid immediately after rain or during drought)
  • Equipment: Use clean sampling tools to avoid cross-contamination between zones
  • Documentation: Export final KML with visited status for record-keeping and future reference
Pro Tip: Export KML files before heading to the field AND after completing sampling. The before-file is your navigation map; the after-file documents exactly where and when samples were collected.
Soil Sampling Tool
Zone-Based Soil Sampling Tool
Battery Management: GPS tracking can drain mobile device batteries quickly. Bring a portable charger or car charger when sampling large fields. The tool uses 5-second update intervals (not continuous) to conserve battery.

Data Attribution

PowerZoner integrates multiple geospatial data sources to provide comprehensive crop productivity and terrain analysis capabilities.

Satellite NDVI Data - Copernicus Sentinel-2:
Resolution: 10 meter pixels
Revisit Time: Every 5 days (two satellites)
Bands Used: Red (665nm) and Near-Infrared (842nm) for NDVI calculation
Processing: Cloud-masked, quality-filtered, atmospherically corrected
License: Free and open data under Copernicus terms
Attribution: Contains modified Copernicus Sentinel data (years displayed in footer)
LiDAR Elevation Data:
US (3DEP): USGS 3D Elevation Program - 1 meter resolution LiDAR
Canada (HRDEM): High Resolution Digital Elevation Model - 1 meter resolution LiDAR
Purpose: Topographic analysis for zone refinement and wetness correlation
License: Public domain (US) / Open Government License (Canada)
Base Map Imagery:
Imagery: ESRI World Imagery - High-resolution satellite imagery
Labels: ESRI World Reference Overlay - Place names and boundaries
Attribution: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community
Weather Data - NOAA GHCN-Daily:
Source: Global Historical Climatology Network Daily
Purpose: Seasonal rainfall indicators for zone interpretation
License: Public domain