Global-Geodetic Profile¶
This module defines the quantized_mesh_tile.global_geodetic.GlobalGeodetic
.
Initial code from:
https://svn.osgeo.org/gdal/trunk/gdal/swig/python/scripts/gdal2tiles.py
Functions necessary for generation of global tiles in Plate Carre projection,
EPSG:4326, unprojected profile.
Pixel and tile coordinates are in TMS notation (origin [0,0] in bottom-left).
What coordinate conversions do we need for TMS Global Geodetic tiles?
Global Geodetic tiles are using geodetic coordinates (latitude,longitude)
directly as planar coordinates XY (it is also called Unprojected or Plate
Carre). We need only scaling to pixel pyramid and cutting to tiles.
Pyramid has on top level two tiles, so it is not square but rectangle.
Area [-180,-90,180,90] is scaled to 512x256 pixels.
TMS has coordinate origin (for pixels and tiles) in bottom-left corner.
Reference¶
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class
quantized_mesh_tile.global_geodetic.
GlobalGeodetic
(tmscompatible, tileSize=256)[source]¶ Bases:
future.types.newobject.newobject
Contructor arguments:
tmscompatible
If set to True, defaults the resolution factor to 0.703125 (2 tiles @ level 0) Adhers to OSGeo TMS spec and therefore Cesium. http://wiki.osgeo.org/wiki/Tile_Map_Service_Specification#global-geodetic If set to False, defaults the resolution factor to 1.40625 (1 tile @ level 0) Adheres OpenLayers, MapProxy, etc default resolution for WMTS.tileSize
The size of the tile in pixel. Default is 256.-
GetNumberOfXTilesAtZoom
(zoom)[source]¶ Returns the number of tiles over x at a given zoom level (only 256px)
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GetNumberOfYTilesAtZoom
(zoom)[source]¶ Returns the number of tiles over y at a given zoom level (only 256px)
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LonLatToPixels
(lon, lat, zoom)[source]¶ Converts lon/lat to pixel coordinates in given zoom of the EPSG:4326 pyramid
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