Lab I Section I: Interactive Conversions

The Interactive Conversions screen of the Geographic Calculator is designed to complete coordinate conversions in an easy and convenient manner. The Geographic Calculator allows the user to convert coordinates from a comprehensive set of coordinate systems. The Interactive Conversions screen is divided into two identical sections. When performing a coordinate conversion, it is necessary to choose one side of the screen as the Source, or Input section. The remaining side becomes the Destination, or Output section. It does not matter which side is used for the Input or Output.

Object:

To convert a point in the Geodetic Latitude/Longitude coordinate system to US State Plane 1927 grid values, save it to a file, and print the conversion information.

Your project calls for coordinates to be stated in the US State Plane 1927 grid. The Geodetic Lat/Long coordinates that you have are:

Latitude:

  44 13 36.96 N

Longitude:

  69 46 08.11 W

SET UP CONVERSIONS FOR OUTPUT TO FILE

It is often desirable to record an interactive conversion for later reference or presentation. This function must be set up prior to the interactive conversion.

To set up the Geographic Calculator for recording the conversion:

  1. Open the Geographic Calculator

  2. Go to File Record Interactive Conversions...

  3. Select a path and file name to which the conversion will be saved.

  4. Click Save.

The calculator will now record the following Interactive Conversion to the file that was just selected.

Follow these steps to complete an interactive conversion of this point:

INPUT PARAMETERS

  1. Click on the Interactive Conversions tab. This will bring the interactive interface onto the screen.

  2. Go to the Coordinate Point Definition area located on the left. This is going to be the Input (Source) side.

  3. Place the cursor in the Name box and title the source point “A”.

  4. Enter the Lat/Long coordinates listed at the beginning of this lab into the North/ South and East/West boxes below the name box. Enter the Latitude value (N) in the Latitude (North/South) field and enter the Longitude value (W) in the Longitude (East/West) field.

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

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

Group:

Geodetic Latitude/Longitude

System:

Latitude/Longitude

Datum:

WGS84

  1. Select the units for your input coordinate system by going to the Coordinate System area and clicking on the Units (center) control button.

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

Angular Unit:

DEGREES

 

  1. Select the format for your input point by going to the Coordinate System area and clicking on the Format control button.

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

Input Format:

DD MM SS.

(All other information on this page controls the output display)

  1. From the Vertical Reference field, select (none). There are no elevation parameters for this conversion.

OUTPUT PARAMETERS

The next few steps will be performed in the Output side of the screen. Remember: It is arbitrarily decided which side is used as the Input side and which side is the Output side.

  1. Go to the “Destination” half of the Interactive Conversions interface.

  2. Type "B" in the Name box.

  3. Define the destination coordinate system . Click on the Define Coordinate System control button.

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

Group:

US State Plane 1927

System:

Maine West 1802

Datum:

NAD27-EAST US

Linear Unit:

USFEET

  1. Select the units for your output coordinate system by going to the Coordinate System area and clicking on the Units (center) control button.

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

Linear Unit:

USFEET

  1. Select the format for your output point by going to the Coordinate System area and clicking on the Format control button.

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

Decimal Precision:

2

 

Note:

Save the conversion settings (Input and Output Coordinate System Settings) by going to FileSave Coordinate System Settings.... The file is saved as a *.css file. Rather than entering in all of the conversion settings information again, this file can be recalled and the parameters are automatically entered into the active dialog.

CONVERSION

  1. Click on the Convert control button on the INPUT side of the interface.

 

The results will appear in the destination area in the corresponding boxes:

North/South:

508217.85

East/West:

604109.29

These are the US State Plane Grid Values for the Geodetic Lat/Long coordinates.

 

Example: Completed Conversion

The coordinate conversion is complete. The conversion data (Original point coordinates, output coordinates, conversion parameters, etc.) can be viewed in a text editor by opening the text file specified before the conversion.

Alternatively, the conversion data can be viewed and printed by going to FilePrint (or clicking the print button). The display can be changed to suit these user’s needs.