# Zonal Grid Statistics

Copyrights (c) 2005 by Volker Wichmann
The module calculates zonal statistics and reports these in a table. The module can be used to create a contingency table of unique condition units (UCUs). These units are delineated from a zonal grid (e.g. sub catchments) and optional categorial grids (e.g. landcover, soil, ...). It is possible to calculate simple statistics (min, max, mean, standard deviation and sum) for each UCU from optional grids with continious data (e.g. slope; aspect must be handled specially, please use the "Aspect" input parameter for such a grid). The number of input grids is only limited by available memory. The module has four different modes of application: (1) only a zonal grid is used as input. This results in a simple contingency table with the number of grid cells in each zone. (2) a zonal grid and additional categorial grids are used as input. This results in a contingency table with the number of cells in each UCU. (3) a zonal grid and additional grids with continuous data are used as input. This results in a contingency table with the number of cells in each zone and some simple statistics for each zone. The statistics are calculated for each continuous grid. (4) a zonal grid, additional categorial grids and additional grids with continuous data are used as input. This results in a contingency table with the number of cells in each UCU and the corresponding statistics for each continuous grid.
Depending on the mode of application, the output table contains information about the category combination of each UCU, the number of cells in each UCU and the statistics for each UCU. A typical output table may look like this:

ID Zone | ID 1stCat | ID 2ndCat | Count UCU | MIN 1stCont | MAX 1stCont | MEAN 1stCont | STDDEV 1stCont | SUM 1stCont
0 | 2 | 6 | 6 | 708.5 | 862.0 | 734.5 | 62.5 | 4406.8
0 | 3 | 4 | 106 | 829.1 | 910.1 | 848.8 | 28.5 | 89969.0

## Parameters

Grid system
Grid system
  Grid system
Zone Grid
Input Grid
  Grid defining the zones to analyse. This grid also acts as a mask. Coding: no-data / categorial values.
Categorial Grids
Input Grid list
  Grids used to delineate the UCUs. Coding: no-data / categorial values.
Grids to analyse
Input Grid list
  Grids with continuous data, statistics are calculated for each grid. Coding: no-data / continuous values.
Aspect
Input Grid
  Aspect grid, in radians.
Zonal Statistics
Output Table
  Summary table.
Short Field Names
Boolean