[OpenLayers-Users] Misplaced markers

[Warren Vick]

Hello all,

 

A newbie to the list and OpenLayers...

 

I've been experimenting with OL and a tile set of my company's own
global data, rendered with Mapnik. I've based my experiments on the
Spherical Mercator example
(http://www.openlayers.org/dev/examples/spherical-mercator.html) and
with just a few changes to the call to OSM, I've got my own tiles
loading beautifully. They align with Google, VE, etc.

 

I hit a problem when placing markers on a map. On placing a marker at a
known coordinate (in Mercator), there is an offset of about 20km to the
north. I'm pretty certain my coordinates are correct. E.g. Dublin
(Ireland) centre at -696564,7012127.

 

So, a few questions:

-          Any idea why my markers are offset? I've tinkered with the {
projection } and { displayProjection } options but with no joy.

-          What determines the coordinate system I should be using when
creating markers?

-          ... and can I override this to LL(WGS-84) which would be my
preferred coordinate format.

 

Regards,

Warren

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