I am using python and owslib to request a WMTS server for tiles in a given region using EPSG:4326 CRS.

I assemble the tiles with PIL by simply pasting them next to each other.

The image I got seems to have projection problem. Especially when I compare it with the same region I got from a WMS server with the same CRS.

The first image is the WMTS built by rendering tiles:enter image description here Don't mind the black border. Also the scale is wrong here. Each layer shows the same distorsion. The band is centered on (48.387943, -4.398273) with a zoom level is 17.

The second image is WMS built:enter image description here The bounding box of the band is (-4.404831817347805, 48.37895984341859, -4.391714182652194, 48.39692615658141)

What am I doing wrong ? Is there something else to do that simply pasting the tiles ?

The server is https://tile.geobretagne.fr/gwc02/service/wmts . There is a WMS server at the same address https://tile.geobretagne.fr/gwc02/service/wms

  • please include the actual images rather than a screen shot, if you could also include the bounding boxes of the requests that may help too – Ian Turton Jun 5 '17 at 8:18
  • There appear to be two questions here, the first is how to assemble a set of WMTS images, the second is why the WMS and WMTS don't match for the same bounding box. Or is the question how to use WMTS and WMS in the same application – nmtoken Jun 6 '17 at 6:54
  • If I divide by a ratio of 1.25 in width, but mutliply by a ratio of 1.25 in height I roughtly get the expected image. I am new to GIS so I don't know what going on. – solsTiCe Jun 11 '17 at 15:28

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