Display custom coordinate system (local projection) in ArcGIS Explorer?

Question

Hi, I'm wondering if anyone has successfully displayed a custom coordinate system in AGX. I'm trying to display a local projection, which is slightly modified from MGA94 zone 56, one of the "core projections" in ArcGIS, but don't know how or whether it is possbile.

I noticed I can choose map projection from Display->Coordinate Systems but it only has the core projections. I'm wondering if there's a way to modify it to include my local projection? Any suggestion will be appriciated!!

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ShellyGill2 · Answer

It seems that the attachment didnt work properly - it reports that the zip is an invalid archive if I try and open it from the forum but the file I'm uploading is fine. I've tried this again a few times and I dont know what's going wrong, but at least for now I have put the EAZ (compiled version of the add-in) up on arcgis.com and shared it, let me know if you wanted the source especially though.

http://www.arcgis.com/home/item.html?id=c46d190084294518ac21e6ad5f13c624

JackZHANG · Answer

Thank you very much Shelly! I'll give a try and let you know how it goes! appriciated!

ShellyGill2 · Answer

I'm trying to display a local projection, which is slightly modified from MGA94 zone 56, one of the "core projections" in ArcGIS [...] I noticed I can choose map projection from Display->Coordinate Systems but it only has the core projections.

There's no way to do this in the application, but you can do this with the SDK. There's a blog post describing it:
http://blogs.esri.com/Info/blogs/arcgisexplorerblog/archive/2010/01/20/changing-the-central-meridian-via-the-sdk.aspx
Some notes for this - it's not a custom 'projection', but I think it still may be what you're after - using a coordinate system based on one of the pre-defined coordinate systems supported in Explorer, but with some of the parameters slightly modified, known as a custom coordinate system. Also note the bottom line which says that custom coordinate systems don't save along with the map (as just the WKID is saved for a coordinate system in the map), so you'd need to reapply this when you re-open the map. (If you have the SDK anyway, then an Extension could be written to do this on startup if you needed to).

I have made a quick add-in Button and attached it here where you can edit the PRJ string (shows the current 2D coordinate system as a PRJ string for editing), and then re-apply it back to the 2D view. I included a compiled EAZ file in case you are not a programmer, and the source in case you are. I tried using the default Web Mercator coordinate system and editing the Central Meridian, and it works fine (note that works for Projected coordinate systems, but it does not work for Geographic coordinate systems).

Regards,

Shelly

CoordinateSystemParams.zip

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