[Talk-GB] reprojected NPE

Frederik Ramm frederik at remote.org
Thu Apr 10 13:26:19 BST 2008


> The main unknown (for me) is the projection of the WMS tile. For
> example, the lat and lon is not constant along the tile edges in
> Mercator. When JOSM requests a tile, does the bbox argument refer to
> the Top/Left and Bottom/Right corner lat/lons or some other method?

It's the lat/lons of the corners. Additionally JOSM will give you the  
desired width and height of the resulting image, thus overspecifying  
the request (width OR height would be enough). If you cannot create a  
recangular image that matches all parameters, then you know that  
either you or JOSM have got the projection wrong.

There is some special NPE map support in the WMS plugin which does  
some kind of re-projection, I never bothered to understand quite what  
it does. Nick Whitelegg would be your man to ask here since he  
implemented the original NPE support for the Landsat plugin, which  
was the precursor of the WMS plugin.


Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"

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