Lab IV Section I: Coordinate Conversion of Map Files

Objective: To convert the coordinate system of a vector map file.

Data: ESRI Shape File

The Geographic Calculator has the ability to convert coordinate systems within vector map files. The Geographic Calculator Map File Conversion function supports the following map file types:

To successfully complete a Map File Conversion, the coordinate system of the original map file must be known. A coordinate conversion that does not have accurate input coordinate system information will not yield accurate results.

Follow these steps to convert the coordinate system of a vector map file:

  1. Open the Geographic Calculator and click the Map File Conversions tab.

  2. Open the Map File for your conversion by going to the File Conversion Settings area and clicking on the Add Files control button.

  3. In the open file dialog that appears browse to the directory where the Getting Started Guide installed its data and select Worcntry.shp.

View One: Worcntry.shp, Geodetic Lat/Long:

(The image above is using the built-in Calculator vector viewer, selected with the button)

  1. Select your Input Coordinate System by going to the Source Coordinate System area and clicking on the Define Coordinate System control button.

  2. A dialog box will appear. Select the following parameters:

Group:

Geodetic Latitude/Longitude

System:

Latitude/Longitude

Datum:

WGS84

  1. In the File Conversions Settings area check the Use output filename prefix check box. This will automatically assign an "output" prefix to the input filename, thereby creating a unique output name.

  2. In the File Conversions Settings area check the Use specific output directory check box and choose the save-to location for your output files.

NOTE: The filetype IN must be the same as the filetype OUT. For example, if the source file is a *.shp file, the output file must be of type *.shp. For this exercise, the output file name should be OUTPUT_Worcntry.shp .

  1. In the File Conversions Settings area click the Auto Generate control button. This will place the output path and filename in the output file box.

  2. Select your Output Coordinate System by going to the Destination Coordinate System area and clicking on the Define Coordinate System control button.

  3. A dialog box will appear. Select the following parameters:

Group:

World Projections

System:

Mercator

Datum:

WGS84

Linear Unit:

METERS

 

Example: Map File Conversion Entries

  1. Click on the Convert control button. This will begin the transformation process. Once the transformation process is complete, a pop-up window will appear (see below).

   

  1. Select "OK".

View Two: Converted Map File

(The image above is using the built-in Calculator vector viewer, selected with the button)

Things to Consider

  1. Each output map file must be uniquely identified by its file extension in order for the Geographic Calculator (and many other applications) to identify it.

  2. The Worcntry.shp has two associated files: