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Raster to Polygon Super slow then not working

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05-30-2013 02:30 AM
DXXX
by
Deactivated User
I have a bunch of rasters that I want to convert into polygons, but when I use the tool it is so slow. 3 hours working on 1 .tif gets too 1%. Anyone have any ideas how I can convert my raster data set into polygons?
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19 Replies
GeospatialTechnology
Deactivated User
Thanks for your response. Can you tell me what options to check to reduce the size? See attached picture.


Just put the new cells size you want in the x and y bits. You can find your current cell size in Source section of layer properties.
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GeospatialTechnology
Deactivated User
Actually please ignore me I just read you comment further up.

How about using the 'Build Boundary' tool on your mosaic dataset?

http://resources.arcgis.com/en/help/main/10.1/index.html#/Build_Boundary/001700000086000000/
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DXXX
by
Deactivated User
All you need to do is build the footprints.  Simply use the ID tool to see the pixel values of the white space in your mosaic dataset and then adjust the settings in the build footprints tool.  By default they are set to eliminate the 0 and 255 pixels. If your rasters have additional values then adjust the min or max values.

You should not have to resample the rasters for this workflow.


The result is ok but still needs a lot of cleaning. Have a look at the screen shot in the attachment. Its a pity the Raster to polygon doesn't work as it should. I am hoping Mark will get back to me and show me what drop downs to select. Please Mark Please.
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GeospatialTechnology
Deactivated User
I already did deedug. Have you tried right clicking on the mosaic dataset in arc catalog then selecting modify and build boundary?
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SteveLynch
Esri Regular Contributor
If you are only interested in the area then you can run the IsNull tool, open the attribute table which will have 0 and a count and 1 and a count.
The count for 0 is the number of cells that are not nodata. Multiply this by the squared cell size.

Steve
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EricRice
Esri Regular Contributor
Its a pity the Raster to polygon doesn't work as it should.


The Raster to Polygon tool isn't really meant for imagery.  The tool is primarily designed for single band integer raster datasets.  If you input a multi-band "image", the tool operates only on the first band.  It will essentially create a polygon for every cell in the input unless of course two or more adjacent pixels share the same value.  If you give it a small raster that is 10k x 10k you'll potentially end up with 100,000,000 polygons.  Raster to Polygon does not and is not intended to create a radiometrically correct footprint feature class.

See Recalculating footprints radiometrically which basically takes you to the Build Footprints tool previously mentioned.  Note, it usually takes playing around with the values, shrink distance, and vertice counts a couple times before you get the desired output.

Best Regards,
Eric
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EricRice
Esri Regular Contributor
Actually please ignore me I just read you comment further up.

How about using the 'Build Boundary' tool on your mosaic dataset?

http://resources.arcgis.com/en/help/main/10.1/index.html#/Build_Boundary/001700000086000000/


The boundary merges all the footprint polygons to create a single boundary  representing the extent of the valid pixels.  So, you have to fix the footprint polygons first, since the boundary layer is basically a  'merge' and 'dissolve' of the footprints.

You can get the footprints very close to how you want them, then build the boundary, and if some minor edits are still required then manually editing shouldn't be all that bad by this point.

I would hold off on optimizing the mosaic dataset (building overviews) until the footprint/coverage is sorted out.

Best,
Eric
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AmandaGibson1
Deactivated User
Any suggestions if I do not have the mosaic dataset extension?

Any word on getting the "create raster index shapefile" extension for 10?  It worked splendidly on 9.3.

Thanks,
Amanda
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JeffreySwain
Esri Regular Contributor
All you need is access to 10 or 10.1 and the ArcEditor or Standard license. The Image Server Extension only comes into play when you want to publish the mosaic dataset.
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EricRice
Esri Regular Contributor
Even if you have just the basic license you can create a raster catalog to get the footprints.  They will be the extent of each image and do not have options like calculating by radiometry which the mosaic dataset has, but it can get you mostly what you want. 

Best,
Eric
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