Knowledge Base

How to import the sea ice trends data into ArcGIS

The following are instructions describing how to import "Sea Ice Trends and Climatologies from SMMR and SSM/I-SSMIS" binary files into ArcGIS. These instructions were tested with ArcInfo 10.0.

1. Rename the Data File.

In order to be able to import a Polar Stereographic monthly climatology sea ice concentration file into ArcGIS, you will need to:

Rename the file extension, adding a .bil

Example: mean.apr.1979-2011.n to mean.apr.1979-2011.n.bil

2. Create a Header File.

In a text editor, create a new file with the content below. You will need to give the file the same name as the data file, but with a .hdr extension. Make sure that the .bil file and the .hdr file are saved in the same folder and are accessible to ArcGIS.

Content of the header file for  Northern Hemisphere data:

nrows 448

ncols 304

nbands 1

nbits 8

layout bil

byteorder I

ulxmap -3837500

ulymap 5837500

xdim 25000

ydim 25000

Content of the header file for Southern Hemisphere data:

nrows 332

ncols 316

nbands 1

nbits 8

layout bil

byteorder I

ulxmap -3937500

ulymap 4337500

xdim 25000

ydim 25000

3. Convert the .bil File to an ESRI Compatible Grid Format.

Start ArcMap and open the ArcToolbox. Select Conversion Tools > To Raster > Raster to Other Format (multiple).

In the dialogue box that opens, select your .bil file as the Input Raster.

In the Output Workspace field, select the location to store the new data file. Choose ESRI Grid, ERDAS Imagine, or TIFF as the output raster format.

Click OK. The program will use your .hdr file to define your input raster and create a new, ESRI-compatible file.

4. Define the Projection.

In ArcToolbox, navigate to Data Management Tools > Projections and Transformations > Define Projection.

In the dialogue box that opens, choose your .bil file as the Input Dataset or Feature Class.

Locate Projected Coordinate System > Polar > NSIDC Sea Ice Polar Stereographic [North/South].

Run the tool.

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