[udig-devel] Custom (hacked) projections

[Dane Blakely Springmeyer]

Hi uDiggers,

In my day job (mapping pacific salmon habitat, rivers, and  
ecosystems) I am constantly projecting spatial data in custom  
projections that place the central meridian in the center of the  
Pacific Ocean (180 longitude). This works perfectly to stitch  
together the North Pacific region of my focus, but tends to produce  
anomalies when switching software apps. For example, I get the error  
"Problem rendering: Latitude 90 degrees N is too close to a pole"  
when I add my data as a layer in uDig.

I have been following the efforts to make relative paths work, and  
therefore to be able to package uDig as a data viewer on a CD. This  
is a feature I'm excited about but this projection issue would hold  
me up. So, I'd be interested if anyone wants to take a crack at  
either explaining to me what it would take to get my custom  
projection to work in uDig or to detail if there is custom projection  
functionality that I am not aware of.

I have posted an example dataset here:

http://danespringmeyer.com/north_pacific_watersheds.zip

it is a hack of the standard world mercator projection:

PROJCS["Clarke_1866_Mercator",GEOGCS["GCS_Clarke_1866",DATUM 
["D_Clarke_1866",SPHEROID["Clarke_1866",6378206.4,294.9786982]],PRIMEM 
["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION 
["Mercator"],PARAMETER["False_Easting",0.0],PARAMETER 
["False_Northing",0.0],PARAMETER["Central_Meridian",180.0],PARAMETER 
["Standard_Parallel_1",47.5],UNIT["Meter",1.0]]


Cheers,

Dane