get boundary of a raster

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02-03-2011 02:22 AM
MauroMarty
New Contributor
It`s probably a simple question, but couldn`t find the tool.

I have raster images and I want to get the boundary of these rasters as a Polygone.
The same would be very convenient for a point shapefile, I`m looking for one boundary shapefile containing all the points.

Thanks,


Mauro
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6 Replies
ShawnLeroux
New Contributor
Hi Mauro,

Not a simple question...I have been working on this as well.
So far, I am using Geospatial Modelling Environment's (spatialecology.com) extractedge function to get a polyline for the raster edge. You can then work with this polyline to make polygons or points. You can probably also use the contour function to get what you want.
Keep me posted if you find a better solution.

Shawn
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JohnSobetzer
Frequent Contributor
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JakeSkinner
Esri Esteemed Contributor
If you have the 3D Analyst extension you can use the 'Raster Domain' tool.  This will produce a polygon or polyline boundary shapefile/feature class.
ChristopherThompson
Regular Contributor
Other approaches to this would be:

  • Convert your raster to a polygon featureclass using the Raster to Polygon tool, populate the Grid-code field with 1 and then dissolve on that value

  • Use Reclass to create a new raster with a single value, and then run the Raster to Polygon tool


One thing to note about the Raster Domain tool is that it seems like it creates a boundary that is 1/2 a cell inside the exterior of the raster dataset - this may be inconsequential for datasets having a very fine resolution but seems like it could become an issue as your dataset gets coarser.
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DonovanCameron
Occasional Contributor II
Great suggestions so far, especially the reference to the arcscripts available.

If you can't get any of those to work, try GDALs gdaltindex function:

gdaltindex output.shp input.tif



For batch processing:
gdaltindex output.shp folder/*.tif


You can open the shapefile in arcgis when finished.

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SeanFadum
New Contributor III
You could also create a mosaic dataset in a geodatabase.  Once you have added your raster(s) to the dataset, you can just bring in the mosaic dataset into ArcMap.  You will notice that associated with this dataset, in the table of contents, is a footprint layer.  These are polygons of the footprints of your raster(s).  You can go into the attributes of this layer and export out which ever footprints you need.
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