grid functions - ObjectVision/GeoDMS GitHub Wiki
Grid functions are used to calculate with data items of grid (two-dimensional) domains, explicitly using the two-dimensional structure of data in a grid, like potential or district.
- dist2 - the distances in a grid towards a point data item
- griddist - impedance in a grid towards the nearest point in a pointset, summing the resistances of the shortest path to the nearest point
- griddist_untiled - griddist with untiled processing (identical result)
- griddist_maximp - griddist with a maximum-impedance cutoff parameter
- griddist_maximp_untiled - griddist_maximp with untiled processing
- griddist_zonal - griddist with a (uint16) zone grid and a zone-boundary impedance
- griddist_zonal_untiled, griddist_zonal_maximp, griddist_zonal_maximp_untiled - combinations of the zonal, maximum-impedance and untiled forms
- griddist_latitude_specific - griddist for EPSG:4326 grids: horizontal steps scale with cos(latitude)
- griddist_untiled_latitude_specific, griddist_maximp_latitude_specific, griddist_maximp_untiled_latitude_specific - the same combinations for EPSG:4326 grids
- griddist_zonal_latitude_specific, griddist_zonal_untiled_latitude_specific, griddist_zonal_maximp_latitude_specific, griddist_zonal_maximp_untiled_latitude_specific - zonal combinations for EPSG:4326 grids
- griddist_maximp - griddist with maximum impedance cutoff
- griddist_zonal - griddist with extra impedance for zone boundary crossings
- griddist_latitude_specific - griddist with latitude-dependent cell sizes
- potential - a neighborhood operation to sum the values of neighbouring cells in a grid, based on a kernel
- potentialSlow - potential with the direct (non-FFT) reference backend; identical result
- potential64 - potential with the float64 FFT backend; identical result
- potentialRaw64 - potential with the float64 FFT backend, without the smoothing step
- potential32, potentialRaw32 - potential with the float32 FFT backend: half the memory, a relative error in the order of 10^-6
- proximity - a neighborhood operation to get the maximum value of neighbouring cells in a grid, based on a kernel
- diversity - the number of different occurrences in the neighbourhood of each cell in a grid
- district - partition according to areas of adjacent (horizontal & vertical, not diagonal) grid cells with the same values
- district_4 - is the district variant that connects cells with equal values via the 4 orthogonal neighbours
- district_uint8, district_uint16, district_uint32, district_uint64 - district variants with a typed district domain
- district_4_uint8, district_4_uint16, district_4_uint32, district_4_uint64 - district_4 variants with a typed district domain
- district_8_uint8, district_8_uint16, district_8_uint32, district_8_uint64 - district_8 variants with a typed district domain
- district_8 - partition according to areas of adjacent (horizontal & vertical & diagonal) grid cells with the same values
- perimeter - for each occurring partition count the number of edges that cells of that partition have with other cells or the raster border
- perimeter_weighted - same, but with provided weights for the North, East, South, and West edges
- raster_merge - to merge data from smaller to larger grids, e.g. to combine country grids to a European grid