Table of Contents

Projection Type

Represents a map projection. Projections can be defined using the predefined options (UTM, Geodetic etc), using a WKT specification, using an EPSG code or using a Proj4 specification.

WKT specifications must follow the WKT standard syntax. See the example below: 

  PROJCS["SUTM21",
      GEOGCS["SOUTH AMERICAN 1969",
          DATUM["SAD69",
              SPHEROID["INT67",6378160,298.25]],
          PRIMEM["Greenwich",0],
          UNIT["degree",0.0174532925199433]],
      PROJECTION["Transverse_Mercator"],
      PARAMETER["latitude_of_origin",0],
      PARAMETER["central_meridian",-57],
      PARAMETER["scale_factor",0.9996],
      PARAMETER["false_easting",500000],
      PARAMETER["false_northing",10000000],
      UNIT["Meter",1]]

The Proj4 syntax must also follow the Proj4 specification syntax. Example: 

  [ +proj=latlong +ellps=GRS80 +towgs84=-199.87,74.79,246.62 ]

GUI Editor

Graphical representation of the projection editor

EGO Script

A constant representing a projection in a EGO Script can be defined in two different ways:

Using ERMapper parameters

[| "COORDINATE_TYPE", "ERMAPPER_PROJECTION", "ERMAPPER_DATUM", "ERMAPPER_UNIT" |]

All parameters are case-insensitive and must be surrounded by double quotes.

Example: 

[| "LATLONG", "GEODETIC", "WGS84", "METERS" |]

Using a WKT (Well-Known Text) description

[| "COORDINATE_TYPE", WKT_PROJECTION |]

The syntax used to the represent the WKT_PROJECTION can be found here.

It is worth nothing that only the COORDINATE_TYPE must be surrounded by double quotes.

Example: 

[| "LATLONG",
   PROJCS["unnamed",
       GEOGCS["WGS 84",
           DATUM["WGS_1984",
               SPHEROID["WGS 84",6378137,298.257223563,
                   AUTHORITY["EPSG","7030"]],
               TOWGS84[0,0,0,0,0,0,0],
               AUTHORITY["EPSG","6326"]],
           PRIMEM["Greenwich",0,
               AUTHORITY["EPSG","8901"]],
           UNIT["degree",0.0174532925199433,
               AUTHORITY["EPSG","9108"]],
           AUTHORITY["EPSG","4326"]],
       PROJECTION["Transverse_Mercator"],
       PARAMETER["latitude_of_origin",0],
       PARAMETER["central_meridian",90],
       PARAMETER["scale_factor",0.9996],
       PARAMETER["false_easting",500000],
       PARAMETER["false_northing",-2000000],
       UNIT["METERS",1]]]
|]

Using a Proj4 description

[| "COORDINATE_TYPE", [ PROJ4_PROJECTION ] |]

The syntax used to the represent the PROJ4_PROJECTION can be found here.

Example: 

[| "LATLONG",
   [ +proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +no_defs ]
|]

Using a EPSG code

[| "COORDINATE_TYPE", EPSG_CODE ] |]

Example: 

[| "LATLONG",
   7030
|]

A COORDINATE_TYPE is also case-insensitive and must be represented using keywords “en” (Easting/Northing), “latlong” (Latitude/Longitude) and “none”. The latter can be used to automatically derive the coordinate type based on the projection parameters.

Automatic Conversions