Knowledge Base

How to import Global Monthly EASE-Grid SWE data products into ArcGIS

The global, monthly SWE EASE-GRID products can be found at the following link:

1. For the first step follow steps 1-4 at the following link that explains displaying Tbs from EASE Grid in Arc GIS:

The only difference is that the data will be from SWE and in binary format (data won’t need to be unzipped when downloaded)
Note: Make sure if using a SWE product from the North Hemisphere that the header is also for the Northern Hemisphere and that they have the same name.

2. Since monthly EASE-GRID SWE data is a 16 bit- signed integer, the data needs to be formatted that way. In ArcGIS open up the ArcToolBox → Go to Spatial Analyst Tools → Then go to Map Algebra → and click on Multi Output Map Algebra. In the new input box, type the following command in the Map Algebra Expression box:

filename* = con(filename >= 32768, filename - 65536, filename)

Click OK.

*In the above example, filename = the new ESRI compatible grid format generated after running through the Importing EASE-Grid  Data steps within Step 1.

Note: Make sure that the syntax for the expression is followed exactly how it is displaced here (ie space between numbers and/or file name) other wise the conversion won’t work or be incorrect.

***New for ArcMap 10*** - you do not need to do the map algebra step any longer.  Modify the header file to include "pixeltype signedint" and the data will be formatted correctly.

eg. southern 25km header:

nrows 721
ncols 721
nbands 1
nbits 16
pixeltype signedint
layout bsq
byteorder I
ulxmap -9024309
ulymap 9024309
xdim 25067.525
ydim 25067.525

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