Bug #1802

problem when using a geographic CRS after changing the central meridian

Added by Giovanni Manghi almost 4 years ago. Updated over 3 years ago.

Status:Closed Start Date:
Priority:Low Due date:
Assigned to:nobody - % Done:

0%
Category:Projection Support
Target version:Version 1.3.0
Platform:All Patch supplied:
Platform version: Affected version:master
Status info:0 Causes crash or corruption:No
Resolution:duplicate

Description

Tested with both shapefiles and postgis.

How to reproduce the problem:

*) download this shapefile of the world borders http://thematicmapping.org/downloads/TM_WORLD_BORDERS-0.3.zip

*) add it to your project

*) add a custom CRS with the following definition (for example) "+proj=moll +lon_0=Central Meridian +x_0=False Easting +y_0=False Northing"

*) in the project properties choose the just created CRS and activate OTFR

*) the layer shows correctly

*) now go to the CRS management and change the central meridian "+proj=moll +lon_0=90 +x_0=False Easting +y_0=False Northing"

*) in the project properties change again to wgs84 and back again to the custom CRS, now the shape looks weird.

*) if you zoom in enough the problem disappear

moll.jpg (41.8 kB) Giovanni Manghi, 07/22/2009 06:50 am

Screenshot.png (13.7 kB) Giovanni Manghi, 07/22/2009 06:52 am

History

#1
Updated by Magnus Homann over 3 years ago

  • Status changed from New to Closed
  • Resolution set to duplicate

This is a duplicate of #597. As you can see the American continent wraps around, which means the polygons should really by split.

Basically, you can't set up your projections such that geometries must be split.

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