Georeferencing and Tiling
Coordinate System
SURE generates georeferenced products whenever the project contains a valid WKT (well-known text) string. All produced tif, las, and laz files contain the georeferencing information assigned to the project.
Whenever the project orientations are specified using a *.prj file, SURE automatically extracts the coordinate system information and uses it for the project. The file coordinate_system.wkt found within the project directory stores the specified WKT string.
The export of Cesium, SLPK, lod_dae, and lod_obj meshes requires a non-local coordinate system. The lod_dae and lod_obj mesh export formats additionally require the "EPSG" field to be within the "PROJCS" field of the WKT string.
GUI
SURE CLI
--coordinate_system file_containing_wkt_string.wkt
Tile Size and GSD
To allow for efficient and scalable processing, SURE divides the surface to be processed into tiles. These tiles are by default sized in a way that ensures that the hardware requirements are respected.
Manually increasing the tile size too much is likely to lead to a crash during processing. Please only do so if you are confident that your hardware can handle it. One way of doing this is by processing a small area (several tiles) before launching a big project.
The default size of a tile depends on the scenario:
Scenario | Tile Size |
|---|---|
AERIAL NADIR | 2000 GSDs |
AERIAL OBLIQUE | 2000 GSDs |
DEFAULT | 1000 GSDs |
The tile size can also be manually defined:
GUI
SURE CLI
--tile_size <tile_size>
The GSD (Ground Sampling Distance) of a project is automatically estimated by SURE. Alternatively, users can specify the project's GSD using the graphical user interface or the command-line interface:
GUI
SURE CLI
--tile_size <tile_size>
When using the AERIAL Nadir scenario with a forward overlap inferior to 80%, SURE doubles the effective GSD used for sizing the tiles and raster products.
Defining the Project's Tiling Scheme
The top-left corner of the 2D region of interest (automatic or manual if available), together with the tile size, defines the horizontal (XY) tiling of a project.
Knowing this principle, it is possible to control the tiling scheme of the project. With the help of the minimum/maximum values of X,Y and the tile size, you can define the arrangement of the tiles in the XY plane. Please use the area 2D / 3D interfaces to do so.
Note that it is also possible to simultaneously work with an area shape file and define the tiling scheme to your preference.