WMTS: Few Things I Want To Remember
- Used to serve prepared rectangular tiles; this means you are limited by web server speed rather than map server speed
- Several ways to retrieve tiles are defined: KVP and REST are mandatory, SOAP is optional
- Does not allow layer combination; additional tile matrix would have to be created
- GetCapabilities, GetTile and GetFeatureInfo requests are defined
- tile
- rectangular representation of space
- defined by tile and row indices
- tile matrix
- set of tiles for a given scale
- defined with:
- tile size derived from standardized pixel size (0.28 × 0.28 mm)
- tile width and tile height (px)
- left upper corner coordinates
- matrix width and height as number of tiles
- tile matrix set
- set of tile matrices for different scales
Total count of tile matrices
nTileMatrices × nTiledStyles × nTiledFormats (if no dimensions are defined)
Total count of tiles in a tile matrix
matrixWidth × matrixHeight
Other equations
pixelSpan = scaleDenominator × 0.28 103 / metersPerUnit(crs);
tileSpanX = tileWidth × pixelSpan;
tileSpanY = tileHeight × pixelSpan;
tileMatrixMaxX = tileMatrixMinX + tileSpanX × matrixWidth;
tileMatrixMinY = tileMatrixMaxY - tileSpanY × matrixHeight;