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Trouble with Generating Spatial Weights Matrix

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01-26-2011 07:20 AM
MichelleDebbink
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New Contributor
‎01-26-2011 07:20 AM
Hi All - I would greatly appreciate a little help with this.  I am trying to create a spatial weights matrix using polygon contiguity (queen); I am a little rusty and can't seem to figure out what I might be doing wrong, but when I load the input feature class into the SWM tool, no fields in the data come up as candidates for the Unique ID.  The drop down menu for Unique ID just remains empty - I have even tried loading some of the ESRI .shp files and still nothing in the drop down menu.  The .shp file contains the polygons (Census Tracts) plus some basic data about each tract (population by race, poverty).  I created a new ID field (type Short Integer) and copied the FID into it when the tract ID wasn't showing up (thought maybe it was a data type mismatch problem since the tract ID is double), but still no luck.  Please help!

Thanks,
Michelle
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1 Reply
LaurenRosenshein
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New Contributor III
‎02-28-2011 02:13 PM
Hi Michelle,

Sorry that you are having trouble generating a Spatial Weights Matrix!!  I have a couple of suggestions that may help.  One suggestion is to try creating a new field of type Long, and calculate the field using the FID/OID.  Then, and this is important, shut down ArcMap, then reopen it and try to use that new field you created.  You may be having trouble with a bug that was fixed at 10.0 SP1 that involves empty selections after new fields are calculated.  Closing down ArcMap seems to do the trick.  And if you haven't installed 10.0 SP1 yet, I strongly encourage you to do that as well.

Another possibility is that the field that you are trying to use does not contain unique values?  The Unique ID has to have a different value for each feature, which is why we suggest using either the FID or the OID for calculating your new UniqID field...just in case.

Sorry for the inconvenience! 

Lauren Rosenshein
Geoprocessing Product Engineer
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