[OSM-dev] openstreetmap, openlayers and overlays

Richard Duivenvoorde rdmailings at duif.net
Thu Jul 5 13:20:12 BST 2007


Hi Artem,
ok, tried that:
http://www.duif.net/googlemapnik.php

looks better (although google seems to have a problem with the kml-file 
I generated by hand: not all 470 points are shown? I looks fine in 
GoogleEarth though).

Will try to make another kml file, and add smaller icons and maybe 
contact OL.

Richard


Artem Pavlenko wrote:
> Hi Richard,
> 
> On 5 Jul 2007, at 09:55, Richard Duivenvoorde wrote:
> 
>> Hi List,
>> I've an OpenLayers page, on which I show the OpenStreetmap (using source 
>> of www.openstreetmap.org <http://www.openstreetmap.org>).
>>
>> I downloaded form geonames.org some points and stuffed them in Postgis 
>> (latlon: 4326). I then used Postgis transform to reproject those points 
>> to 51001 / 41001 (aka using proj string:
>> <41001> +proj=merc +lat_ts=0 +lon_0=0 +k=1.000000 +x_0=0 +y_0=0 
>> +ellps=WGS84 +datum=WGS84 +units=m +no_defs  no_defs <>
>> )
>>
>> Showing those points as overlay on a googlemap seems fine:
>> http://www.duif.net/GoogleGeonames.jpg
>> But putting them on OSM they seem shifted (or map is shifted?):
>> http://www.duif.net/OpenStreetsGeonames.jpg
>> (the big dot in the middle are supposed to be in the city of Amsterdam)
>>
> 
> Hmm... both OpenStreetMap and Google are using the same tile schema. You 
> can see this on : http://media.mapnik.org/oxford-osm.html (just pan/zoom 
> to Amsterdam) and they overlap correctly. 
> 
> I suspect OL is doing something different for TMS and Google layers. You 
> can try exporting KML from postgis and overlay it  on top of OSM, using 
> GMap interface. If that works you should post to OL list. 
> 
> Cheers
> Artem
>  
> 
>> My question:
>> - do I do something stupid here?
>>
>> - does anybody else succeeded in putting custom (latlon) points as 
>> overlay on openstreetmap?
>>
>> - has somebody some viable explanation for the shift? (at this moment I 
>> cannot put this stuff on the live server, but if neccessary I will do 
>> that).
>>
>> TIA
>>
>> Richard
>>
>> ps if you think this questions belong on the userlist: let me know, I 
>> just thought here was more interest and knowledge about these kind of 
>> stuff
>>
>> _______________________________________________
>> dev mailing list
>> dev at openstreetmap.org <mailto:dev at openstreetmap.org>
>> http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/dev
>>
> 
> Artem Pavlenko
> http://mapnik.org
> 
> 
> 





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