View Full Version : Wilbur Coordinate System

06-22-2010, 12:38 AM
Hi everyone,

I had a quick question about using Wilbur: I have a map (in .mdr format) that I've been working on recently, and I'd like to re-adjust the coordinate system to change my longitude measurements. I'd like to set the prime meridian to be somewhere in the middle of the ocean (see attached image) instead of running through the southeastern island as it is now. How can I go about doing that? I'm sure it's a simple fix, but for the life of me I can't figure it out. Thanks!


06-22-2010, 04:15 AM
Under "mapinfo" you can change the coordinates. You probably want something like 90 for top, -90 for bottom, -72 for left and 288 for right. The 0 meridian should end up somewhere in the ocean with these settings. If not you will have to play a bit more with the left/right settings, just make sure that right-left=360 holds true.

06-22-2010, 12:10 PM
Ah yes, that did the trick. Thanks! Now, for the next step: is there a way to get the program to re-draw the map so that the prime meridian is on each edge of the map? Basically, I just want the continent not to be cut in half.

06-23-2010, 01:02 AM
Try Filter>>Other>>Toroidal Rotation with Y Samples=0 and X Samples=# pixels that you want to shift the map by. If you do that then you won't need to adjust the coordinate system. Assuming that your image is about 1000 pixels across then about 250 for X ought to be about right (use a negative value to get the rotation to go the other way).

06-23-2010, 12:08 PM
Thank you, waldronate, that solved my problem exactly.