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Automatic Classification Bug?

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12-01-2009 08:18 AM
ChrisCorwin
Frequent Contributor
I was using Spatial Analyst to Extract by Attribute. I have a raster that was created using Observer Points. So there is 16 fields in the Raster table. I was extracting for each field equal to 1. So that I have a raster of the cells that is seen by that one observation point. While doing this, I checked my TOC and noticed the seventh one that I extracted had been automatically classified with unique values based on the field values and was not a stretch classification like the rest. (Btw, my Observer Points shapefile is classified with unique values based on another field)... and the 16th one.. But the rest were all stretched.
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EricRice
Esri Regular Contributor
When a single-band raster dataset is drawn, the rules for determining the default renderer are as follows:


  • If your dataset has a color map, it will be displayed with the Colormap renderer using the colors stored in the color map.


  • If your dataset contains 1-bit data and the dataset does not have pyramids, the Unique Values renderer will be used with 0 set to white and 1 set to black. When 1-bit data has pyramids, the Stretched renderer will be used. Pyramid files for 1-bit data are created as 8-bit grayscale to achieve improved display when viewing the raster at its full extent.


  • If your dataset contains 25 or fewer unique values, the Unique Values renderer will be used with random colors assigned to the values.


  • If your dataset has an internally stored custom stretch, the Stretched renderer will be used with a color ramp from black to white.


  • If your dataset has statistics, the Stretched renderer will be used with a color ramp from black to white and a value of 2 will be applied for a standard deviation stretch. If there are no statistics for your dataset, the Stretched renderer with a color ramp from black to white will still be used, but the values won't be stretched.


Please let me know if you have any questions or if this isn't applicable. 

Regards,
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