Projection File

This is a data file which contains the parameters for all the allowable projections which will be handled by the program.

File Format
The file is a Comma Separated value (CSV) file and it contains one projection definition per line with the parameters separated by commas. The first line consists of headings for the columns.
Filename = MapProjections.csv

The file must be located in a directory with all the other sting and symbol definition files. the location is defined in File/Settings/Program Settings/Reference Files...

Column Name Contents
1 Group The Group number allows grouping of datums for the same region, e.g. for Australia AGD was used prior to 2000 and GDA since then. If these datums have the same group number, it is assumed that there is a way to transform data from one to the other. In the USA the NAD27, NAD83 and NAD83HARN would all be in the same group.
2 Datum Name The name of the datum ‘GDA’, ‘NAD27’
3 Radius Radius of the earth
4 Earth Flattening Ratio difference between the major and minor earth radii
5 Projection Type Mercator or Lambert
6 Projection Name Name of the projection ‘UTM Zone 56’
7 Origin Latitude Latitude of the projection origin
8 Origin Longitude Longitude of the projection origin
9 Origin Easting Easting at the projection origin
10 Origin Northing Northing at the projection origin
11 Central Scale Factor The scale factor at the origin
12 Co-ordinate Units Units: Metres, Feet or ‘US Survey Feet’
13 Standard Parallel1 Reference parallel for Lambert Projection
14 Standard Parallel2 Reference parallel for Lambert Projection

Entries with the same group number - the user can transform data between the datums.

Entries with the same datum name - the user can transform data between the projectsions (subject to restriction on longitude).

For an explanation of Datums History, click here.