Combining WMTS of api.geo.admin.ch with G* Maps or OpenStreetMap

[Stefan Keller]

Dear all

I'd like to combine the WMTS of api.geo.admin.ch with other WMTS (like
G* Maps or OpenStreetMap) using OpenLayers.
These other WMTS are not in EPSG:21781 but typically EPSG:900913
(being an alias to EPSG:3857).
Here we have a raster re-projection problem.
According to [1] this seems feasible by using proj4js - but I doubt if
this works and how performant it is (OpenLayers loads up to 60 tiles
which all have to be reprojected.)
Does anyone have experience with this?

Yours, Stefan

P.S. I know MapProxy but I really want to do this reprojection in the
client.

[1] http://wiki.openstreetmap.org/wiki/OpenLayers_Simple_Example#Use_Proj4js_for_other_transformations

[Marc Monnerat]

Hello Stefan,

The only thing I a aware is the gdalwarp-js library, loosely based on
a HTML5 and canvas work by Klokan Petr Přidal. There are some demos
around, but only reprojecting WMS.

Marc

> [1]http://wiki.openstreetmap.org/wiki/OpenLayers_Simple_Example#Use_Proj...

[Alexander Gabriel]

Hi

We (Fachstelle Naturschutz Kt. Zürich in a project related web-app) have the same interest. We're using wms from Kanton Zürich serving diverse layers, maps and aerial fotos. The performance is very spotty though, at times the maps don't build up for minutes. We want to serve google aerial fotos as fallback for these situations. So they would have to be combined with layers using EPSG 21781.

Alex

Am Mittwoch, 13. März 2013 schrieb :

Hello,

I'm also interested by this issue, as I already have a map (openstreetmap and gmaps) and methods using OpenLayers API and I don't want to switch to geoadmin, so I would like to add a new swisstopo layer

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[Moullet Cédric swisstopo]

Hi,

All the examples of client side reprojection that I have seen are not performant, so I’m not sure that it’s the way to go (but this could change with OpenLayers 3 and the usage of WebGL).

In addition, the reprojection degrades the quality of the original tiles.

For swiss applications, I can only recommend to work with EPSG:21781.

Cédric

 

De : geoadm...@googlegroups.com [mailto:geoadm...@googlegroups.com] De la part de Alexander Gabriel
Envoyé : mercredi 13 mars 2013 15:50
À : geoadm...@googlegroups.com
Objet : Re: Combining WMTS of api.geo.admin.ch with G* Maps or OpenStreetMap