Generating Shapefiles from Drone Imagery Using Agisoft

Jul 22, 2024

How to Generate a Shapefile from Drone Imagery Using Agisoft

Presenter: Randy Price

Affiliation: LSU AgCenter

Overview

  • Purpose: Create a shapefile from drone imagery for use in precision farming software or consoles for spray applications.
  • Tool Used: Agisoft

Steps to Generate Shapefile

  1. Open Orthomosaic: Wheat Field Example

    • Drone: DJI Mavic Mini (red, green, blue images)
    • Process: Captured ~60 images to create an orthomosaic
    • Result: Loaded orthomosaic with visible high and low spots

  2. Preparing to Generate Prescription Map

    • Current File: In JPEG, TIFF, or a GIS file not useful for precision farming
    • Goal: Convert to shapefile with useful data
    • Action: Generate Prescription Map

  3. Creating Single Value Map Using Indices

    • RGB Data: Each pixel has a value from 0 to 255 for red, green, and blue
    • Purpose: Convert RGB data into a single value number for each pixel
    • Tool: Raster Calculator
      • Example Equation: Green - Red / (Green + Red - Blue)
      • Output: Single number map (e.g., NDVI)
    • Steps: Transforming data
      • Green - Red Calculation
      • Apply Transform
      • Result: Single value map (0-1 range)
      • Color Palette: Can use heat scale or NDVI

  4. Setting Up Prescription Map

    • Objective: Map different levels for variable rate applications (e.g., fertilizer)
    • Select Areas: Define different zones/levels (e.g., 20, 40, 60, 80 kg/ha)
    • Example Setup:
      • Good growing area: 20 kg/ha
      • Better growing area: 40 kg/ha
      • Unsure area: 60 kg/ha
      • Poor growing area: 0 kg/ha
    • Parameters: Adjust settings
      • Number of Areas
      • Cell Size
      • Boundary File (if available)
    • Saving: Export as shape file (e.g., Prescription Map - 5 Rates)

  5. Verification and Usage

    • Save File: Remember the save location
    • Verification Tools: Use tools like Google Earth Pro for verification
    • Process:
      • Import shapefile
      • Check different rates and colors for accuracy
    • Final Step: Use shapefile in precision farming software or console

Conclusion

  • Instructor: Randy Price, LSU AgCenter
  • Support: Available for assistance with generating shapefiles from drone imagery
  • Remarks: Equations may vary, but method ensures correct zone identification and action decisions.

Notes

  • Ensure correct conversion rates (e.g., kg/ha to lbs/acre)
  • Customize indices equations based on specific needs

Contact Information: Randy Price, LSU AgCenter.