Adding OSTN02 to ArcGIS Explorer Build 2500

This is a quick walkthrough of how to apply OSTN02 to ArcGIS Explorer build 2500, it assumes a Windows 7 install, though this fix will work with XP.

First download & install the Projection System expansion pack: http://resources.arcgis.com/en/communities/arcgis-explorer-desktop/01s000000017000000.htm#ESRI_SECTION1_5F289729636840309B87C664AEEF4249

Then navigate to the ArcGIS Explorer program folder, this can be found at: C:\Program Files (x86)\Explorer (x86)\

Navigate to the projection engine (pedata) folder:

Add a new folder and call it “united kingdom”:

Next you need to download the OSTN02 transformation from Ordnance Survey, the zipfile can be found here: http://www.ordnancesurvey.co.uk/business-and-government/help-and-support/navigation-technology/os-net/ostn02-ntv2-format.html

Select the “Download OSTN02 NTV2 data” option:

Within the zipfile you will see 3 files, the only file you need is the OSTN02_NTV2.gsb file.  Copy this into the “united kingdom” folder you created.

The transformation should now work!! Start up ArcGIS Explorer desktop and load in a OSGB36 dataset, go to the map properties and select “2D Coordinate System”, when you click on “Transformation” next to OSGB36, you should see this: