Help Topics/Data Sets/NOAA

How do I import SNODAS data into ArcGIS?

Kara
posted this on July 7, 2011, 13:34

Question:

How do I import SNODAS data into ArcGIS?

Answer:

Follow the steps below (which are also linked to from the data set documentation). These steps will work for all 8 SNODAS variables using ArcGIS 10.0 or higher. If you ordered data using Polaris, scroll down to ‘Import Steps for Data Ordered from Polaris’. If you are working with data retrieved from FTP, use the following instructions: 

In this example I will be importing snow depth data from March 1, 2015.

filename= us_ssmv01025SlL00T0024TTNATS2015030105DP001.dat


1. Create the following header file and give it the same name as "filename" but with a .hdr extentsion. Remember to place in the same directory as "filename.dat"

nrows 3351
ncols 6935
nbands 1
nbits 16
pixeltype signedint
byteorder M
layout dat
ulxmap -124.729583333331703
ulymap 52.871249516804028
xdim 0.00833333333
ydim 0.00833333333 


Note: this header file came from page 12 of Barrett, A. 2003. National Operational Hydrologic Remote Sensing Center Snow Data Assimilation System (SNODAS) Products at NSIDC. NSIDC Special Report 11. Boulder, CO, USA: National Snow and Ice Data Center. 19 pp.  The header information may be different for individual files. See the header file provided with each data file during FTP download for specific information.

2. Start ArcMap and open ArcToolbox. Select Conversion Tools > To Raster > Raster to Other Format. The Raster to Other Format window will appear. In the Input Raster box, browse and select the .dat file. In the Output Workspace box, select the location to store the new data set. In the Output Format box, select the format you wish to create (e.g. TIFF, ENVI DAT, etc.). Click OK.

 

Import Steps for Data Ordered from Polaris

If you are working with spatially subsetted data through our Polaris interface and output your data in the native binary format, the header file will be different. Each data file is delivered with a .dat.sub.txt file that you will need to reference. Your header file should contain:

ncols xxxx   (corresponds to Image Width in .dat.sub.txt file)
nrows xxxx (corresponds to Image Height in .dat.sub.txt file)
nbands 1
nbits 16
pixeltype signedint
byteorder I
layout dat
ulxmap xxxx (corresponds to Upper Left Corner X Coordinate in .dat.sub.txt file)
ulymap xxxx (corresponds to Upper Left Corner Y Coordinate in .dat.sub.txt file)
xdim 0.00833333333 
ydim 0.00833333333 

 

 
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