[OSM-dev] OpenLayers problem with latitude and longitude placement

Thomas Wood grand.edgemaster at gmail.com
Sun Dec 7 17:40:41 GMT 2008

A particularly good guide to spherical mercator and projections with
openlayers is at http://docs.openlayers.org/spherical_mercator/
OpenLayers has a history of very sparse documentation, but they're
trying to fix that for their next release. Inheritance of bounds,
max/min resolution/scale/numZoomLevels, from the Map object to
individual Layers is fairly complex. In general, this type of Map
options should match those of the base layer. In particular, see the
last paragraph of the linked article.

This is also quite a good OpenLayers overview tutorial
http://workshops.opengeo.org/openlayers/intro/doc/en/ (as linked from

2008/12/7 Ulf Lamping <ulf.lamping at googlemail.com>:
> Thomas Wood schrieb:
>> A few things
>> The maxExtent set on the Map object must be in the projection defined
>> on the Map object
>> The maxResolution option on the Map object is currently not doing
>> anything at a guess, this is what is causing the vectors to disappear
>> at >z13
>> The units are not degrees on this map (but that option doesn't do
>> anything important)
> Hi!
> Do you have any idea where I can find documentation about this?
> The OL examples don't explain this stuff a lot and I couldn't find anything
> in the API docs. Even a pointer to the specific sources would be helpful.
> I'm currently doing lot's of trial and error ...
> Regards, ULFL

Thomas Wood

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