Supported projections
ArcPad supports the Extended Backus-Naur Form (EBNF) definition for a string representing a coordinate system.
The element of this string that represents the projection, starts with the word PROJECTION, followed by the specific name of the projection, enclosed in quotes and square brackets. The coordinate systems that ArcPad supports list in the thousands, but these coordinate systems are all based on one of the following projections:
- Geographic
- Gauss_Kruger
- Transverse_Mercator
- Albers
- Lambert_Conformal_Conic
- Cylindrical_EqArea
- New_Zealand_Map_Grid
- Stereographic
- Double_Stereographic
- Hotine_Oblique_Mercator_Two_Point_Natural_Origin
- Hotine_Oblique_Mercator_Two_Point_Center
- Hotine_Oblique_Mercator_Azimuth_Natural_Origin
- Hotine_Oblique_Mercator_Azimuth_Center
- Krovak
- Rectified_Skew_Orthomorphic_Natural_Origin
- Rectified_Skew_Orthomorphic_Center
- Cassini
- Mercator_Auxiliary_Sphere
- Lambert_Azimuthal_Equal_Area
For example, WGS_1984_Web_Mercator_Auxiliary_Sphere is supported, because PROJECTION["Mercator_Auxiliary_Sphere"] is supported.
The above projections cover all UTM projections, for example, AMG, MGA, and many national grids. State Plane is covered by the Transverse Mercator, Lambert Conformal Conic, and Hotine Oblique Mercator Azimuth Natural Origin projections.
You can view the list of supported projections by running the Export Projection Information tool. This tool creates a number of files in the ArcPad System folder, including the Export_Projections.txt file. This file lists all the ArcGIS Projection Engine projections, and notes whether or not each projection is supported by ArcPad. The projection parameters are also listed, as illustrated by the following extract of the Export_Projections.txt file for the Transverse Mercator projection:
43006,Transverse_Mercator
*** Supported ***
100001,False_Easting,0
100002,False_Northing,1
100010,Central_Meridian,2
100003,Scale_Factor,5
100021,Latitude_Of_Origin,6
Note:The Export Projection Information tool was removed from the default toolbars in ArcPad 8. It can be readded or added to a custom toolbar in Toolbar Settings.
Do not edit the Export_Projections.txt file, as it is not used by ArcPad.
Using your own coordinate system
Several hundred sample projection files (.prj) are installed with ArcPad on your PC in the Coordinate Systems folder, located in your ArcPad installation folder. These projection files are the ArcPad supported subset of files distributed with ArcGIS 10.0. As of ArcGIS 10.1, projection files are no longer included in the ArcGIS install. If you want to use a projection that was introduced in ArcGIS 10.1 or later, you still can. To generate the PRJ file using ArcMap:
- Choose Properties on your data frame.
- On the Coordinate Systems tab, select the coordinate system and add it to Favorites.
- On your file system, browse to C:\Users\[UserName]\AppData\Roaming\ESRI\Desktop[Version]\ArcMap\Coordinate Systems. You can copy this newly created .prj file to your ArcPad project.
You can also use other existing projection files or create your own projection files with the following criteria:
- The PROJECTION component of the .prj file is one of the supported projections listed above.
- The DATUM component of the .prj file is one of the datums defined, either in the ArcPad internal datum tables or in Transforms.dbf.
Developers can also add support for additional projections and datum transformations by building custom projection and datum transformation extensions using ArcPad Studio.
Checking if projection information is understood by ArcPad
You can check if ArcPad has understood, or correctly interpreted, the projection information in the projection file (.prj) or projection strings sent by servers or extensions to ArcPad. Open the Map Properties dialog box and tap the Projection tab. All the names and values listed on the Projection tab should be identical to the names and values listed in the projection file (.prj). If they are not, the most probable cause is that there is an error in the projection file or ArcPad does not support the projection.
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