User:Ff5722/Using Photoshop and Illustrator for tracing

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https://youtu.be/RjBblVax36I

In Photoshop

  • Open image file in Photoshop (should be in the correct projection)
  • Use magic wand or quick selection tool to select desired feature
  • If the selection edges are also containing undesired features, choose from the menu Image > Adjustments > Black and white, and set the level for the desired colour at minimum to sharpen the edges
  • Open the paths window (menu>window>paths)
  • In the top right of the path window, click the drop down menu
  • Click 'Make work path'
  • Tolerance: 1px for low res imagery
  • Menu > File
  • Export > paths to illustrator > Save as *.ai

In Illustrator

  • Open the file you exported
  • File > Save As > Save as SVG

In JOSM

  • Get the ImportVec plugin if you haven't already
  • Drag the SVG to JOSM window
  • It may be stuck at 'opening files', simply close that dialog
  • In the import vector graphics dialog set the scale. For example, if your source image has a resolution of 10m per pixel, and you saved paths with a resolution of 1px, then when converting back, you should again choose 10m per unit.
  • Curve steps is at 4 by default, this should be ok, but you can simplify later.
  • Click OK in the dialog
  • Move around the imported ways to align them. Depending on the projection, you may have to split and align parts individually.
  • Simplify if needed
  • Add appropriate tags
  • Validate and upload