I have a pdf of a street map which is many different colors depending on land use.

enter image description here

I need to import it into ArcMap and then digitize it. Obviously I could manually create each feature but that would take days. I've done some reading and it appears that I can use the ArcScan method to automatically create vectors from the pdf.

I have converted it to a tif image and then imported it into ArcMap. I understand it needs to be two colors only in order to get ArcScan to work. I try reclassifying the raster with just two classes to make it two colors but when I do this I lose a whole bunchof the streets. This seems to be because they fall into certain landuses which are colored specifically (purple, blue orange and green). I have tried manually assigning the breaks, but it seems that all of these colors are lumped into one group right at the end of the distribution graph in the classification, so there's seemingly no way to separate them which results in me losing all this data.

Does anyone know a way around this, or a better way to quickly digitize street map data from a pdf in arcmap?

  • 1
    You might open the tiff in a photo editing program, use the color picker to select each land zones color and then fill them with white or delete their color entirely if you can, and then save the image not as RGB but as an indexed raster. If you don't have a good photo editing program you can use the free GIMP.
    – johns
    Sep 25 '15 at 13:07

You could just increase the thickness of all important lines and decrease the other ones using GIMP (or Photoshop), something like this (it's in spanish, but sure you can get the idea). This would be done in order to "classify" your areas in somehow, even though you will get only two colors (ie., 0s and 1s). Besides, as you use ArcScan, you can also edit your shapefile so you can include the names of every feature you select.


Instead of using software to try and separate multiple colours you could print your PDF file (the bigger the better) and then over the hardcopy place a transparent drafting film like mylar so that you can use a thin black pen to draw over the lines by hand much quicker than you could heads up digitize.

If you scan this then you have a two color and very clean image ideal for ArcScan or any raster to vector conversion tools.

  • Thanks PolyGeo. Once I do that and carry out the ArcScan, how do I then add back in the landzone use?
    – John
    Sep 25 '15 at 7:15
  • Would you be able to include a picture of/from your PDF in your question to show us what you are dealing with, please?
    – PolyGeo
    Sep 25 '15 at 7:41
  • You draw the zoning polygon outlines, raster to vector convert the lines, use Feature To Polygon to polygonize your lines, add a field to your polygons and then edit to assign attributes to the 20 or so zoning polygons in that PDF.
    – PolyGeo
    Sep 25 '15 at 11:00
  • Tried printing the file and the lines didn't show up on the print. Is there any other way to digitize the map?
    – John
    Sep 25 '15 at 11:15
  • Turn it into a TIFF, georeference and heads-up digitize - but I thought you had abandoned that.
    – PolyGeo
    Sep 25 '15 at 11:26

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