I have the raster below which I want to convert to a set of vector lines: Raster Lines

As you can see, there are small breaks in the lines and some bits are double-width. I want to be able to reliably import these sort of images to a vector in ArcGIS.

I've spent a lot of time trying to get tools like Integrate, Extend Lines, Trim Lines and Unsplit Lines to do what I want, but I just can't seem to achieve it. I guess this problem must have been experienced before, does anyone have any ideas for a workflow that would do what I want?

I thought of maybe trying to clean up the raster before-hand, but I'm not sure how to go about that.


Scan2cad has a free set of Image cleanup tools. You can dilate the Pixels to close the gaps, then thin the pixels. Despeckle,etc.

Bring the image into ArcGIS, raster to polyline.

To find the remaining gaps, save the line end-points as points (feature vertices to points). Run Near, setting a max search distance. Arc 10 has more advanced snapping tools. You can use your points file that have another end point within a distance to select your lines for snapping.

I cannot find an ESRI tool that creates polylines from points. You might be able to adapt this, http://arcscripts.esri.com/details.asp?dbid=13147

  • Thanks - some really good ideas there. Do you have a link to the free image cleanup tools from Scan2Cad? I can't seem to find them on their website. – robintw Jan 20 '11 at 23:51
  • 1
    The cleanup tools are part of the regular software. Download the Trial version. scan2cad.com The image tools never time-out. Good luck. – klewis Jan 21 '11 at 0:17

You may want to look at ArcScan:

ArcScan provides tools that allow you to convert scanned images into vector-based feature layers. The process of converting raster data to vector features is known as vectorization. Vectorization can be performed manually by interactively tracing raster cells or automatically using the automatic mode.

The interactive vectorization experience, referred to as raster tracing, requires that you trace the raster cells in the map to create vector features. The automated vectorization experience, referred to as automatic vectorization, requires that you generate features for the entire raster based on settings that you specify.

From the ArcScan home page:

Starting with the release of ArcGIS 10.1, ArcScan for ArcGIS is included in all license levels of ArcGIS for Desktop software at no additional cost.

So all you need to do to use it is follow the instructions on the Enabling the ArcScan extension page:

Before you can start using ArcScan, you must enable the ArcScan extension in ArcMap.

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