Classifying raster layer

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06-08-2016 10:02 AM
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New Contributor

Hey there,

hope someone knows what to do.

When i try to classify my raster layer ArcGis shows me an error.(translated from german) "Error while initializing the render "classify": possible reason: too many unique values"

What's wrong?

Thanks for reading

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MVP Esteemed Contributor

Go to C:\Program Files (x86)\ArcGIS\Desktop10.4\Utilities and run the AdvancedArcMapSettings.exe and change the value to something larger... within reason

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New Contributor

I changed the maximum number of classes to 256 in the AdvancedArcMapSettings but it still doesn't work.

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MVP Notable Contributor

Vincent,

How many classes are you needing? How far do you get before you get an error? What type of classification are you using? Which software and version are you running?

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New Contributor

Im running 10.4 for Desktop. Well, I only need about 4 or 5 classes. When I go to symbology in the layer properties and click on classify, the error message shows up.

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MVP Esteemed Contributor

you can't use unique then, you will have to regroup/reclassify the data.  The average person can't distinguish more than about 20 colours/patterns anyway.  what scenario would require that many classes anyway?

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Regular Contributor II

If you want classifying a raster , don't use Unique Values (as in the picture below )

unique values will give each cell value a color and any cell that has same value, and you will have thousands of colors. that not classify.

Using Stretched (recommended)

or classify a raster using Classified , and you will have to use a method to class the range of values ( don't let classes to be over than 10 class )

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New Contributor

The problem is, when I click classified, arcMap says, that there are too much unique values(when I click on unique values, there are none listed). Streched works fine, but I need my output classified.

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MVP Esteemed Contributor

as I pointed out in a previous post, there is a limit, you will have to consolidate some of the classes.  If you need 256+++ classes, then there is no point mapping it since no one is going to be able to distinguish anywhere near that.  And before you think, moving to vector world, it can't be done either.  You are going to have to rethink what it is you are trying to convey and how best to do it. 

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MVP Notable Contributor

Vincent,

I agree with Dan. As Abdullah pointed out, try not using classified and try using stretched or discrete color in your symbology.