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I'm new to GIS and I work with ArcMap.

I have a layer with an orthophoto of a graveyard. On top of that, a layer with an old scanned map of the same area showing all graves.

I would like to make a layer of all the graves.

I do this by first drawing some help lines along the borders of each grave, then I draw a polygon feature, and then use the Cut Polygon Tool to cut it along the help lines.

enter image description here

Is there some way to speed up this process? Like a tool that cuts the polygon automatically along the help lines. That sort of recognizes all lines that cross the selected polygon and then cuts it into smaller polygons along the lines.

  • 2
    Adding a simple picture would help others to understand what you are trying to achieve... – Alex Tereshenkov Jun 18 '15 at 9:34
  • Are you trying to automatically vectorize a georeferenced scanned map? Have you looked into arcscan? help.arcgis.com/en/arcgisdesktop/10.0/pdf/arcscan-tutorial.pdf – Aaron Jun 18 '15 at 14:10
  • The scanned map is more of a help on the way of getting correct area of the grave. But the scanned map is old and incorrect in many ways. No, I'm just looking for a quick tool that after I drawed the polygon over the pink help lines cuts/clip the polygon into smaller ones... – Fredrik Jun 18 '15 at 14:31
  • I'd like the layer with help lines to cut the layer with the polygons. – Fredrik Jun 18 '15 at 14:35
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I'm not aware of a geopgrocessing tool in ArcMap that will split polygons by polylines. (The Union tool will split polygons by other polygons.)

I would suggest a change in your workflow, which should help you achieve your end goal. Instead of drawing your "help lines" as polylines, why not draw them as polygons? It will save you the step of having to draw the polygons later, and should make things go faster for you.

A few tips to make this digitizing directly to polygons easier:

  • If your plots are all rectangular (which it looks like they are in your screenshot), you can use the Rectangle Construction tool to draw your boxes rather than digitizing to the four corners of the grave plot. See "Creating Rectangular Polygons" on this page.

    enter image description here

  • Symbolize your polygon layer to be semi-transparent, located in the Properties Window on the Display Tab. This enables you to see what is underneath your polygons, while also being able to see which areas are covered by polygons. (Thanks to ChrisW for the suggestion.)

    enter image description here

  • Turn on snapping for Points, Ends and Vertexes (not Lines) to get your grave polygon boundaries to accurately line up with one another.
    enter image description here

  • Hm, ignore the scanned map. Perhaps a mistake of mine to mention it. Let's say I only have the Orthophoto of the graveyard and want to make polygons of the graves. I want to make it as exact as possible, but at the samte time having fairly straight rows. Hence using the help lines first, I find them more easy to move then moving vertexes of a polygon. That's why I then am in need of a cutting tool after I create the polygons on top the help lines. But if there no such way I guess I have two options: Continue as before or finding another work flow... – Fredrik Jun 18 '15 at 14:49
  • @Fredrik Someone may know of a tool that will cut the polygons by polylines. You might want to review the Overlay Geoprocessing tools: resources.arcgis.com/en/help/main/10.1/index.html#//… – Sara Barnes Jun 18 '15 at 15:04
  • I'd suggest an alternate version to your second tip. If you change symbology to just outline, it can quickly become difficult to tell which areas you have actually covered with a polygon and which are simply completely surrounded by other polygons. Instead of no fill, leave the fill set to a color and go to the Display tab. There you can change the transparency of the layer - I usually use 40-60%, but it depends on colors used and what you're trying to see. This will make the entire layer semi-transparent, so you can see through it but it's still quite obvious what is or isn't covered. – Chris W Jun 27 '15 at 20:33
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ETGeoWizards has a Split Polygons with Polylines tool in their polygon menu. The tool is included in the free download but I believe there are limitations on file size. Information can be found on the website: http://www.ian-ko.com/

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There are several ways to tackle this problem, and available solutions depend on your license level. Most require higher than Basic or a third party tool.

First, to answer the direct question of splitting a polygon with a line, see other duplicate questions here:

There is a geoprocessing tool in Arc that will do it, as mentioned at those questions, called Feature to Polygon. However, it requires an Advanced license. There are also other solutions that require add-ons or custom tools, also mentioned at those questions.

Alternatively you can change your workflow as suggested by Sara. If you're already drawing all the lines anyway, you can directly convert them to polygons in a couple of ways as long as you're creating fully enclosed regions. Again, the Feature to Polygon tool will do it but requires an Advanced license. Another alternative called Construct Polygons on the Advanced Editing toolbar is available at either the Standard or Advanced license level (but not Basic). It is discussed at two other questions here:

Your current method of drawing one big polygon and cutting it up is fewer clicks (18 for a row of 8 graves) than drawing each polygon individually (32 clicks, possibly fewer depending on auto-complete methods).

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