MapProxy can be configured to use a WMTS as a source, exposing the source data as a WMS and optionally a WMTS. This page walks through the process of configuring MapProxy to request data from the Get Mapping Aerial WMTS. The benefits of this approach are: the customer specific API key is hidden from end users; the base mapping is make available as both WMTS and WMS (for printing in iShare GIS); base map tiles are cached locally improving performance.
MapProxy config
The test MapProxy instance is configured via D:\mapproxytest\mapproxy.yaml and available in a local browser on the server via http://localhost:84/ and http://localhost:81/iShareGISTEST.WebLocal/mapproxy/ (via a Rewrite rule). The test instance has the MapProxy demo available at http://localhost:84/demo/.
Review WMTS capabilities
The first thing to do is to open the WMTS in QGIS the available Layers and TileMatrixSets that the WMTS is capable of providing.
Once you have tested the layers in QGIS and decided which are of interestopen the capabilities XML document in a browser to view the details of the WMTS that will be required to configure MapProxy.
Of particular interest:
The URL that GetTile requests must be sent:
The Layers (one in this instance). We’re interested in the ows:Identifier (layer name), Formats and the names of the TileMatrixSets (tile grids). Here I’ve highlighted the layer name 2021_UK_100mm and the OsEPSG27700Scales TileMatrixSet which we will use.
I’ve selected the OsEPSG27700Scales TileMatrixSet as it uses numeric Identifiers for each TileMatrix which is currently the only format supported by MapProxy. I have a branch which contains support for non-numeric TileMatrix Identifiers which might make it into MapProxy in future.
The OsEPSG27700Scales TileMatrixSet looks like this:
Creating a grid
In the MapProxy config (D:\mapproxytest\mapproxy.yaml) we first define a grid, then a source which uses that grid, followed by a cache which uses the grid and source and finally a layer which uses the cache 
. The grid is configured according to these instructions: [MapProxy] seed a WMTS service and create a WMS service.
The final grid looks like this:
grids:
getmapping__os_gb__grid:
origin: nw
bbox: [0, 0, 700000, 1344000]
bbox_srs: 'EPSG:27700'
srs: 'EPSG:27700'
tile_size: [250, 250]
res: [
# res level scale @90.7 DPI
896.0000000000, # 0 3200000.00000000
448.0000000000, # 1 1600000.00000000
224.0000000000, # 2 800000.00000000
112.0000000000, # 3 400000.00000000
56.0000000000, # 4 200000.00000000
28.0000000000, # 5 100000.00000000
14.0000000000, # 6 50000.00000000
7.0000000000, # 7 25000.00000000
3.5000000000, # 8 12500.00000000
1.7500000000, # 9 6250.00000000
0.8750000000, # 10 3125.00000000
0.4375000000, # 11 1562.50000000
0.2187500000, # 12 781.25000000
0.1093750000, # 13 390.62500000
]
The name of the grid which will be used elsewhere in mapproxy.yaml is getmapping__os_gb__grid
The origin is generally nw for an WMTS compatible grid.
The SRS values are taken from the ows:BoundingBox and ows:SupportedCRS elements
The bbox is derived from ows:BoundingBox.
Tile size from TileWidth and TileHeight (not sure why they don’t just use the default of 256 or 512).
The resolutions are derived from each of the ScaleDenominator values via the scales command of the mapproxy-util command-line tool as follows in cmd.exe:
cd /d d:\MapProxyTest\ venv\Scripts\activate mapproxy-util scales --as-res-conf 3200000 1600000 800000 400000 200000 100000 50000 25000 12500 6250 3125 1562.5 781.25 390.625
The above, changes to the MapProxy install directory and activates the Python virtual environment (which provides access to the mapproxy-util script) before calling mapproxy-util scales with the list of scales to convert to resolutions. The output from the command is then copied to the grid in mapproxy.yaml.
Creating source
A source will requests tiles from the Get Mapping WMTS in order for them to be cached. The final source looks like this:
sources:
getmapping__2021_UK_100mm__os_gb__wmts:
type: tile
grid: getmapping__os_gb__grid
url: https://www.getmapping.com/GmWMTS/NNNNNNNN-NNNN-NNNN-NNNN-NNNNNNNNNNNN/ORG.wmtsx?Service=WMTS&Request=GetTile&Version=1.0.0&Format=image%%2Fpng&layer=2021_UK_100mm&style=Default&tilematrixset=OsEPSG27700Scales&TileMatrix=%(z)s&TileCol=%(x)s&TileRow=%(y)s
transparent: true
The name of the source is getmapping__2021_UK_100mm__os_gb__wmts.
It’s a tile source which uses the getmapping__os_gb__grid grid we have just defined.
We’ve set transparent: true in this instance so we can combine data from this source another later on.
The url is a template which MapProxy will update with appropriate values in order to fetch a given tile. We’re specifying the layer (2021_UK_100mm), the tilematrixset (OsEPSG27700Scales) and format (image/png) and using placeholders for TileMatrix (zoom level), TileCol and TileRow.
Creating a cache
A cache uses the source and grid we have just defined, there are a few options for where cache data is stored, we’re using the default file cache.
caches:
getmapping__2021_UK_100mm__os_gb__cache:
grids: [getmapping__os_gb__grid]
sources: [getmapping__2021_UK_100mm__os_gb__wmts]
The tiles can be found in D:\mapproxytest\cache_data.
Creating a layer
A layer defines a WMS or WMTS layer that MapProxy will make available to clients.
layers:
- name: getmapping__2021_UK_100mm__os_gb
title: '2021 10cm Digital Aerial Photography (Get Mapping OS grid)'
sources: [getmapping__2021_UK_100mm__os_gb__cache]
The name is the used in WMS GetMap and WMTS GetTile requests.
The title is the friendly name commonly displayed in desktop clients such as QGIS.
The sources property is a list of either direct un-cached sources or caches from which to request data. I this instance we’re using the cache we’ve just defined (getmapping__2021_UK_100mm__os_gb__cache).
Testing and debugging
You can test the MapProxy config via the demo service: http://localhost:84/demo/ and via QGIS by adding a WMS or WMTS source:
