[OSM-dev] WMSC - bachelor thesis

sorel johann johann.sorel at geomatys.fr
Wed Aug 17 23:26:20 BST 2011


hi again.

see inline

On 17/08/2011 23:01, Oliver Tonnhofer wrote:
> On 17.08.2011, at 22:06, sorel johann wrote:
>> 3) TMS
>> - minimaliste capabilities, lacks starting point coordinate, number of available pyramid depth, tile size, number of tiles on x/y
>> those simple missing informations makes tms unusable unless the user already knows them.
> You will find all that information in the capabilities. See: http://osm.omniscale.net/proxy/tms/1.0.0/osm/EPSG900913
Do all TMS, mapnik or others provide this capabilities document ? same 
xml schema ?

>> 1) WMTS
>> + provide all requiered informations to properly place tiles in any position
> That's not completely true. It only describes the top left coordinate and scale denominator. The client needs to know if the projection is in meter, feet or degrees to convert the scale to resolution, so that it can calculate the lower right corner. Don't know what they where thinking…
WMTS gives you the projection code. so you know what are the projection 
axis and units.
If your library can't provide those informations, you should change, 
handeling projections
is the De-Facto thing that makes a GIS library, It's just a cartesian 
library like hundred others if it can't.

beside I don't understand why you need the resolution to find to lower 
right corner,
you have the grid size, the size of a tile and the top left corner 
coordinate, nothing more needed.

johann








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