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Cell definition

Started by jonebr04, August 23, 2014, 05:02:55 PM

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How are "cells" in SLAMM defined? On page 21 of the Technical Documentation it says that each of SLAMM's cells may be composed of more than one category, which suggests that the SLAMM cell size is not the same size as the raster inputs.


Jonathan S. Clough

They're the same size.  Currently inputs are required to be 100% of the cell size.  As cells evolve there can be partial conversion of cells that would be reflected in tables of data but raster outputs show the dominant class in a given cell.   Best -- J



Hello - I have 2 more questions about grid cells.

(1) Each time-step raster output has a different number of total grid cells?  Why is this happening?  The input nwi file and the initial nwi output have the same number of grid cells, but any time-step after that has a different number.

(2) In the output table, the area of undeveloped dry land seems to be off by one decimal place...

Thank you!

Jonathan S. Clough

We have never seen what you refer to in observation (1).  In my experience, SLAMM does not lose or gain grid cells.  Can you show us an example of this symptom?

With respect to (2), which decimal place?  Is this machine accuracy?  To save memory space, SLAMM utilizes single-precision mathematics.

Best regards -- Jonathan


Thank you for your response.  Both questions ended up being issues with the GIS attribute table.  Everything is matching correctly now!