[gdal-dev] WMTS support in GDAL

[Even Rouault]

Le jeudi 30 avril 2015 02:33:47, Jeremy Palmer a écrit :
> Is it now possible to read WMTS sources using the GDAL WMS driver? The case
> looking at is using a service such as
> https://data.linz.govt.nz/set/2-nz-aerial-imagery/webservices/ and which
> has custom tile matrix specification and a RESTFul Tile access API.

Hi Jeremy,

There is no dedicated WMTS driver (or WMS "mini-driver"). However in 
particular - but common-  cases, for example when the tiling scheme is the 
GoogleMapsCompatible one, and more generally when all resolution levels have 
the same origin point, and their resolution differ by a factor of 2, you can 
use a definition of the WMS TMS mini-driver.

In your case, you can put the following content in a .xml file and it will work 
(adapted from http://www.gdal.org/frmt_wms_openstreetmap_tms.xml).

<GDAL_WMS>
    <Service name="TMS">
        <ServerUrl>http://tiles-a.data-
cdn.linz.govt.nz/services;key=327224a02cc4453ba183441bbb6267aa/tiles/v4/set=2/EPSG:3857/${z}/${x}/${y}.png</ServerUrl>
    </Service>
    <DataWindow>
        <UpperLeftX>-20037508.34</UpperLeftX>
        <UpperLeftY>20037508.34</UpperLeftY>
        <LowerRightX>20037508.34</LowerRightX>
        <LowerRightY>-20037508.34</LowerRightY>
        <TileLevel>20</TileLevel> <!-- limited to 20, instead of 21 since GDAL 
block array would require much too memory -->
        <TileCountX>1</TileCountX>
        <TileCountY>1</TileCountY>
        <YOrigin>top</YOrigin>
    </DataWindow>
    <Projection>EPSG:3857</Projection>
    <BlockSizeX>256</BlockSizeX>
    <BlockSizeY>256</BlockSizeY>
    <BandsCount>4</BandsCount>
    <Cache />
</GDAL_WMS>


A proper driver would infer that from the capabilities, and possibly deal with 
the annoying cases I mentionned (the fact that overviews in WMTS may have not 
the same origin point is the most annoying one)

Even

> 
> Cheers,
> 
> Jeremy Palmer
> Data Services Group Manager
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