USGS Binary Grid (.adf) file conversion to ASCII Grid (.asc) file conversion to EDX (.gcv) file conversion

The purpose of this document is to provide the steps needed to create an EDX clutter (.gcv) file starting with USGS raster binary grid (.adf) files.  The process is done in two parts.

Part 1 - Convert USGS raster binary grid (.adf) files to raster ASCII grid (.asc) file

There are a number of 3^rd party Geographic Information System that supports most geospatial vector and raster file types and database formats. Unlike many other open source GIS programs, QGIS is available for a number of operating systems, including both Windows and Mac OSX.  QGIS (previously known as Quantum GIS) is a cross-platform, free, and open-source desktop geographic information system (GIS) application that provides data viewing, editing, and analysis.

Download QGIS

Select the ‘Latest release for New Users’ (either 32 bit or 64 bit, depending upon your operating system)

After downloading and installing QGIS, launch the ‘QGIS Desktop’ application for that release.

Load the binary raster (.adf) files:

1. At the QGIS main interface, from the menu bar, select Project>New

2. From the menu bar, select Layer>Add Layer>Add Raster Layer

Open

This opens a file selection dialog box. Navigate to the folder where the raster binary “.adf” files are located and select ALL the “.adf” files (use Ctrl-A to select ALL files in the folder).  Click the Open button to load the files and close the dialog box. The binary raster layer will now display in the main map view of QGIS.

Convert the binary raster (.adf) file to ASCII raster (.asc) format

From the menu bar, select Raster>Conversion>Translate (Convert Format) which opens a Translate (Convert format) dialog box.

Open

The Input Layer field will have the name of the “.adf” file to be converted. For the Output file, click the Select button which opens a Select the raster file… dialog box.  Navigate to a folder where you want to create the raster ASCII “.asc” file and then enter a name for the file in the File name field.  For the Save as type make sure to select the following and then click the Save button to exit:

Back in the Translate (Convert format) dialog box, the bottom of the box will show the path and file name for the input layer and the path and file name for the output file.  Click the OK button to initiate the conversion.  If successful, you will see a ‘Process completed’ message and a process status message. Click OK on both boxes to close them.

Close the Translate (Convert format) dialog box and then from the menu bar, select Project>Exit QGIS to close the application. Click the Discard button when prompted to save the project.

Part 2 - Convert Arc/Info ASCII Grid (.asc) file to EDX (.gcv) file

This part of the process uses the EDXCV utility for the conversion.  The utility and the pdf instruction manual can be accessed from either:

1. The SignalPro menu bar:

2. Utilities>File Conversions (Run EDXCV)

3. Help>EDXCV Utility

4. The Signal or SignalPro installation folder:

5. <installation_drive_letter>:\Program Files\EDX\SignalPro\bin\edxcv.exe

6.  <installation_drive_letter>:\Program Files\EDX\SignalPro\help\EDXCV_Manual.pdf

If you have created a clutter merge file in order to convert the USGS clutter codes to a different set of clutter codes, you need to do the following before running the EDXCV utility conversion:

A.    The clutter merge file must be named ‘clutter_merge.ini’ and should be of the format described in the EDXCV_Manual under the section: 8.6 ArcView® ASCII Grid to EDX .GCV format

B.    Place the clutter merge file in the same folder as the “.asc” file that was created above in Part 1. 

Launch the EDXCV utility and when it opens, from the selection menu, click File>New

Next, click Conversions>Land use (clutter) file conversion and the following dialog box will display:

For the Source file, input the file path and name or click Browse to select the location and name of the ASCII grid “.asc” file and click Open.

For the Destination, input the file path and file name (.gcv) or click Browse to the select folder and file name (.gcv) of the EDX clutter file to be created. The destination file can have the same name as the source file, but change the file extension to “.gcv”.

In the Conversion drop-down list, select ArcView ASCII Grid to EDX .gcv format.

Next click the Set geographic parameters button and the following dialog box will display:

To determine how to complete this dialog box, using a text editor, view the contents of the “.prj” file that was created in the folder along with the “.asc” file.  Following is an example of the contents of a “.prj” file:

PROJCS["Albers",

GEOGCS["GCS_North_American_1983",

DATUM["D_North_American_1983",

SPHEROID["GRS_1980",6378137,298.257222101]],

PRIMEM["Greenwich",0],

UNIT["Degree",0.017453292519943295]],

PROJECTION["Albers"],

PARAMETER["standard_parallel_1",29.5],

PARAMETER["standard_parallel_2",45.5],

PARAMETER["latitude_of_origin",23],

PARAMETER["central_meridian",-96],

PARAMETER["false_easting",0],

PARAMETER["false_northing",0],

UNIT["METERS",1]]

In the dialog box for:

the Map projection drop-down list, select the same as the PROJECTION value.

the Reference longitude field, use the "central_meridian" numeric value.

the Reference latitude field, use the "latitude_of_origin" numeric value.

the Standard parallel 1 field, use the corresponding value.

the Standard parallel 2 field, use the corresponding value.

the False easting field, use the corresponding value

the False northing field, use the corresponding value.

If source file was created using lat/long w/ decimal degrees, check the radio button for Source file uses latitude/longitude AND check the radio button for Decimal degrees, otherwise, select the Source file uses x,y meters radio button.

Click the OK button to save the changes.

Back in the Land use (clutter) file conversion dialog box, click Start conversion button and the utility will run the conversion to create the new “.gcv” file.

Once the conversion completes, the following message appears:

 Click the Yes button to see the info on the “.gcv” file that was created. Verify the display shows the correct x min/max and y min/max coordinates for the clutter data.

 Select File>Exit to close the utility.