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Raster Calculator problem.

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02-16-2011 05:00 PM
ChristopherBlinn
Emerging Contributor
Hello,

I think I may be trying to do something out of my GIS capabilities...

I want to use the raster calculator to create a "relative elevation" DEM.  Currently I have a DEM of an entire state.  The DEM has a 10 meter resolution.  I want the raster calculator to read the input cell value, and then apply a buffer and search the values of the cells within that buffer (say 1000 meters from the input cell) and take the average of those cell values.  Then I want the output DEM to be made of the average values.  Also, I want the new DEM to have a resolution of 1000 meter resolution.

Am I dreaming too big here? If possible, I am pretty sure it will involve some Python scripting.  I am working with ArcGIS 10.0 if that helps in any.  Any feedback is helpful and thank you in advance!
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8 Replies
DanPatterson_Retired
MVP Emeritus
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PatrickTaurman
Deactivated User
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ChristopherBlinn
Emerging Contributor
Thank you all for your replies.  Let me work with these grid tools and post back any updates.
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ChristopherBlinn
Emerging Contributor
Ran the focalstatistics, and the output raster was a solid black rectangle. Bad right? Well, although it was all black, each cell was calculated correctly and has a significant value.  The symbology of the raster however is all screwed up.  Any ideas why?
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ChristopherBlinn
Emerging Contributor
Any way to identify these outliers? Then run a con statement to make sure when the script runs these cells do not have extreme values? Just ideas at this point.
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ChristopherBlinn
Emerging Contributor
Okay, so here's the situation.

My original raster has a range of values from 180.8 to 4132.9.  The output raster after running the focal statistics has a range of values from 256 to 3969.2.  The focal statistics script I ran was:

FocalStatistics("RASTERNAME",NbrCircle(1500,"MAP"),"MEAN")

There appears to be no outliers in my data.  Now, could NoData cell values be causing this error?  If so can I run the following to correct for the problem?

FocalStatistics(Con("RASTERNAME","RASTERNAME","",FocalStatistics("RASTERNAME",NbrCircle(100,"MAP"),"MEAN")),NbrCircle(1500,"MAP"),"MEAN")

I think this script would fill the NoData values with an average value calculated by the neighborhood created.  Maybe I am wrong.

I am sorry if I am not making too much sense, I am very new to working with rasters, much of my experience is in vector-based GIS work.
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ChristopherBlinn
Emerging Contributor
Attempted running that script, received two errors, 539 and 999999.

Guess I need to try something else.
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ChristopherBlinn
Emerging Contributor
Did you know that the "-" symbol can cause a bunch of problems because of syntax rules? Me either, until about 5 minutes ago.
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