Using raster attribute other than 'value' in map algebra

[PeterHarrel]

In the old Single Output Map Algebra statement, I could specify which raster attribute I wished the operation to be performed on by listing attribute name in the following format: raster.attribute. 

For example, a habitat raster with multiple attributes in addition to 'value' could be multiplied by a mask raster in SOMA by typing:
mask * habitat.type
where 'type' was a different attribute. 

This does not seem to be possible in the ArcGIS 10 Raster Calculator.  Is there another option?

[EricRice]

Hi there,

Dot notation is not currently possible in the new map algebra framework.  However, you can make a call to the Lookup tool within the map algebra expression.  This tool is designed to make a raster from an attribute of the input raster.  Once the you have the Lookup result you can multiply it by your mask.

Regards,
Eric

[MelissaHart]

Eric,

It appears that the Lookup tool treats 0 in the value field as NODATA, even when you're calling another attribute.

This is problematic when 0 is a valid entry.  Any suggestions?

Thank you!

[SebastianGatscha]

I have the same problem. I want to make a SetNull calculation using the "Count" of a raster and not Value.
There must be an easier way of doing that, then using the Lookup function.

No Suggestions???

[EricRice]

I have the same problem. I want to make a SetNull calculation using the "Count" of a raster and not Value.
There must be an easier way of doing that, then using the Lookup function.

No Suggestions???

SetNull has a parameter for the Where Clause.  You can use the Count field there.

[EricRice]

Eric,

It appears that the Lookup tool treats 0 in the value field as NODATA, even when you're calling another attribute.

This is problematic when 0 is a valid entry.  Any suggestions?

Thank you!

Melissa,

I can't reproduce that issue.  Can you please log an incident with Esri Support so we can get the data and try to replicate?

Eric

[MelissaHart]

Melissa,

I can't reproduce that issue.  Can you please log an incident with Esri Support so we can get the data and try to replicate?

Eric

We will do that, Eric -- thanks!

[WaylonDaniels]

It is now June 2011.  Has this problem been resolved? 

"Dot notation is not currently possible in the new map algebra framework."

How are we to use raster attribute values in Map Algebra or the SA Math functions in ArcGIS10?

Thanks,
Dwain

[JeffreySwain]

The lookup tool will create a raster that has the value that you are looking for.  This concept of dot notation does not exist in python processing used in the Python Window, so you will have to create a new raster with the value desired and the processing can be done.  

There is an enhancement request that exists to return that functionality.  Please log a support incident to add to that enhancement request.

[ChrisSnyder]

#START SHORT RANT

Why is it that ESRI chooses to not port certain existing functionality from earlier version of their software to newer versions?

Spatial Analyst/Grid Examples:
--------------------------------------
1. dot notation
2. docell
3. ability to run concurrent SA processes

Why not, as a first priority, port all the existing functionality, concentrate on making it better/faster, and then come up with new additional tools/functionality as a second priority???

From a user's point of view, it is very frustrating having to submit an "enhancement request" for functionality that had existed for decades, but then mysteriously disappears... Yarr!

#END SHORT RANT