What's new in ILWIS 3.3?

Spatial Multiple Criteria Evaluation (SMCE)

The existing SMCE application has been extended with the following options:

  • Overlay of reference maps on the input/output maps of the application;
  • It is now possible to use non-spatial criteria, allowing the combination of spatial and non-spatial MCE;
  • The standardization of value criteria is assisted by interactive function graphs.

DEM hydro-processing operations

New applications for DEM hydro-processing have been implemented:

  • Topological Optimization, to improve the results when the input has undefined values;
  • Variable Threshold Computation, to help preparing a threshold map for drainage network extraction;
  • Drainage Network Extraction, to extract a basic drainage network;
  • Drainage Network Ordering, to assign a unique identifier to each stream;
  • Catchment Extraction, to construct catchments for all unique streams;
  • Catchment Merge, to merge adjacent catchments;
  • Overland Flow Length, to calculate the overland distance towards the 'nearest' drainage for each pixel according to the flow direction map;
  • Compound Index Calculation, to calculate a number of maps relevant to watershed management, soil erosion and conservation studies;
  • Horton Statistics, to calculate the number of streams, the average stream length, the average area of catchments for Strahler stream orders;
  • Aggregate Statistics, to calculate statistics after crossing a merged catchments map with a DEM;
  • Cumulative Hypsometric Curve, to obtain cumulative area values for all height values in a single catchment;
  • Class Coverage Statistics, to obtain areas in percentages of a class map within a single catchment.

Georeference editors

  • Support for sub-pixel precision in tiepoint editors;
  • Support up to 8 fiducial marks for the inner orientation of orthophotos;
  • Support for affine and projective inner orientation;
  • Support for 3D coordinate transformations using 7 or 10 datum parameters.

Import and export using the GDAL library

GDAL (http://www.gdal.org) was added as an extra library, next to the ILWIS native library and GeoGateway, for the import and export of raster maps.

Satellite projections

The projections GeoStationary Satellite, GeoStationary Satellite View and MSG Perspective are added to support coordinates in images originating from geostationary satellites. The three versions implement three variants of the algorithm for coordinates.

Calculation and statistical functions for map lists

  • MapList Statistics: calculates average, median, minimum, maximum and standard deviation for a map list;
  • MapList Graph: given a location, a Z-plot is created of a map list;
  • MapList Calculate: performs any calculation on map lists with the same number of maps;