Error opening shapefiles in ArcGIS Explorer

[ErikWilson]

I have created a .shp file in HGIS.  they are outlines of fields from my farm.  They were created using Lon/Lat coordinate system and WGS84 Datum. 

When I try to open these files in ArcGIS Explorer, I get an error.  "Failed to add shapefile. (Unknown Coordinate System)"   Any ideas on the problem.

[ShellyGill2]

I get an error.  "Failed to add shapefile. (Unknown Coordinate System)".

When you get this error, its indicating that the shapefile has no accompanying .prj file - this contains coordinate system information for a shapefile - Explorer will not assume a coordinate system, so you need to specify one. The prj file should have the same base filename as the rest of the files comprising the shapefile set.

If you cannot get hold of an existing .prj file for the right coordinate system, you can use the Explorer SDK to create a .prj file (see the CoordinateSystem.ExportToPrjString method). It's probably easiest to just get an existing one though.

[ErikWilson]

Is this a common file set?  Using HGIS I get a .shx, .shp, .dbf files.  No .prj.  Will I have the same issue using ArcView 9.3?  We are planning purchasing the software in the next few days.  All my data uses the above mentioned file set.

[DonCopple]

You should be able to bring in your file to 9.3.  It will give you a warning and may not project with other basemap information that you have at first, but you can define the projection in 9.3.  This will write a .prj file and then it should open smoothly from then on in 9.3 or Explorer.