[Qgis-developer] OpenLayers plugin bug

[Brent Wood]

Hi,

I have a problem with this very useful plugin.

If I load a Postgis dataset which includes points across 180, for data captured around New Zealand, using longitudes in the 0-360 space (which is valid data for EPSG:4326) they plot fine in QGIS.

If I then start the plugin & use a Google/Yahoo/etc basemap, the points are (usually) initially in the correct place and plot OK. Sometimes the points in the W hemisphere fail to render, sometimes they are OK. This is on a zoomed out map.

As I zoom in, QGIS starts to omit the points in the W hemisphere altogether, even in the configurations that were OK when zoomed out. QGIS also sometimes starts to offset the points from the basemap, so that the western points on the map plot at an increasingly offset position, and the eastern points are missing. As I zoom back out, this offset is retained and the map fails to overlay the points correctly.

I'm assuming this is related to the plugin switching the canvas to EPSG:3857 and failing to support the 0-360 longitude coordinates. Given Proj.4 is used as the reprojection engine, there should be no problems with the 0-360 coords being correctly mapped to EPSG:3857, as in my experience Proj.4 (cs2cs) has supported 0-360 input seamlessly for some years now.


Is there any simple fix I can apply? If some funding is required to make the plugin work correctly across 180 with 0-360 longitude data, this is possible.   



inTHANKSvance


Brent Wood
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