Making Contour Maps with Sketchup for Permaculture Designs

Getting good contour maps for your permaculture design can be tricky. This method uses free software and data sources. You’ll end up with a nice 3D model you can view, and contour lines overlaid on a satellite image in a vector format, for higher quality finished designs.

Prerequisites

  • SketchUp (free 3D design software)
  • Inkscape (free vector illustration software)
  • Basic operating knowledge of the above software

Overview

We’re going to use SketchUp to pull satellite imagery and terrain heights from Google, create contour lines on the terrain, export the satellite imagery and contour lines as images, and import them into Inkscape to create the base layer for a permaculture design.

The contour lines are created by intersecting a bunch of regularly spaced rectangles with the 3D model of the terrain.

This process has a lot of steps but can be done quickly with a little practice.

In addition to creating the base layer for a design, the 3D model with contours created in SketchUp is also useful for initial site assessment by orbiting and zooming in and out.

SketchUp

  1. Start a new SketchUp document
  2. Delete the scale model person
  3. File / Geo-location / Add location
  4. Make the map window as large as possible to get the most resolution in your images
  5. Enter an address or zoom in to the site
  6. Position the map window and zoom so that the site fills the window
  7. Click Select Region
  8. Move and resize the selection window until you’ve got it just right
  9. Click Grab
  10. Camera / Parallel Perspective
  11. Camera / Standard Views / Top
  12. Camera / Zoom Extents
  13. File / Export / 2D Graphic
  14. Use file type PNG with options Use View Size, Antialias, Transparent Background
  15. Save as <site name> satellite.png
  16. File / Geo-location / Show Terrain
  17. Draw a rectangle larger than the size of the terrain
  18. Move it down so it doesn’t intersect at all with the terrain
  19. Copy-move up the rectangle (start moving then press Control or Command to make a copy)
  20. Type in the size of the contour you want (e.g. 5′ or 10′) and press Enter
  21. Multiply the rectangle by typing in 50x or 100x and pressing Enter
  22. The rectangles should extend above the highest point of the terrain. Undo and repeat if you didn’t have enough or way too many.
  23. Select All and make a group
  24. Edit the group
  25. Select All and make another group
  26. Right-click and Intersect Faces / With Model
  27. Select the rectangles and delete them
  28. Exit group edit mode
  29. Camera / Standard Views / Top
  30. Camera / Zoom Extents
  31. View / Face Style / Wireframe
  32. Resize the Sketchup window so that any empty space on the sides of the terrain are minimized
  33. File / Export / 2D Graphic
  34. Use PNG file format with options Use View Size, Antialias and Transparent Background
  35. Save as <site name> contours.png
  36. Save the SketchUp model if you want to return to it later. Otherwise just close SketchUp.

Inkscape

  1. Start a new Inkscape document
  2. File / Import the satellite image saved earlier
  3. Turn on snap to page border
  4. Line up the bounding box (dotted line box) to one of the page corners
  5. File / Import the contour image saved earlier
  6. Line up to the same corner
  7. With the contour image selected, go to Path / Trace Bitmap
  8. Use the default settings and click OK, then close the Trace Bitmap window
  9. Change the contour lines color to something more visible for the type of terrain. White or yellow is better on green trees, but black is better on drylands.
  10. Select All and create a group so that the contours stay aligned with the satellite image
  11. Move and scale the image so it fits better on the page