[GIS] ArcGIS Raster Calculator output raster has one band but cannot build attribute table

arcgis-10.1arcgis-desktopraster-calculatorreclassifyspatial-analyst

I built a raster using the raster calculator of ArcGIS 10.1 for Desktop.

The properties of the output raster ("usle_1") indicate that this raster has one band.

There is no attribute table but I want to reclassify the values in the raster, so I open the "Build attribute table" tool.

When I input "usle_1", it gives me an error:

Only single band integer raster dataset is a valid input.

I tried saving the raster as a .tif, to no avail.

Any ideas for how I can reclassify this raster in order to use it in another raster calculator equation?

Best Answer

Here's something I have done many times in the past. You can use the Raster Calculator and Convert your values to Integer. However, before doing so, I strongly recommend looking a bit deeper into your raster values.

For example, if you know how many significant digits you want your data in, then you can just multiply the current rasters by a factor then convert that value to Integer.

To illustrate, say I a raster type float, and I determine that the data values are only necessary up to 4 decimal points, I can use the Raster Calculator to do:

Int(raster * 10000)

This will multiply all of my raster values by 10,000 (moving the decimal 4 places to the right) then convert the number to an integer.

After you create your raster attribute table, add a field to it, and you can divide the raster value by 10,000 if you need a field to show a more accurate value for each raster pixel.

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[GIS] reclass, raster calculator

If you provide more detail on how you reclassified and the specific raster calculation used to get the empty data raster (usually indicated by -3e20 to +3e20) that will be helpful in troubleshooting the problem.

Assuming ArcGIS with Spatial Analyst, if reclassify and raster calculator are giving you empty output then try the following two tools to achieve the result you need:

Set Null can be used to set all other values not equal to the one you're interested in as NoData - a much more straightforward method than reclass to change values to NoData.

Extract by Mask can then be used to isolate cells within the other raster wherever there are values in the set null output. And then you can use this masked raster when calculating the corresponding equation (or more efficiently use the SetNull output as a mask in the environments and calculate on the original land raster).

Perhaps a more simplified approach will be to use the Con tool to apply your separate equations inside conditional statements for different land types. Basically, they may look something like this (substitute with your file names):

Con(LandRas == 1, (type equation 1 here), 0)
Con(LandRas == 2, (type equation 2 here), 0)
Con(LandRas == 3, (type equation 3 here), 0)

[GIS] Build Raster Attribute Table from .tif with pixel type of float or double

The solution to this problem is to multiple your grid by 100 to move the digits to the left of the decimal point. I suggest 100 as your example are to 2 decimal places, if it were 3 then you multiple by 1000. After the multiplication you may need to run your dataset through the INT tool to make sure it is converted to an integer grid.

Do your analysis then divide by 100.

Best Answer

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[GIS] reclass, raster calculator

[GIS] Build Raster Attribute Table from .tif with pixel type of float or double

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