The dialogues for Integer Codes function essentially same as those for Stationary Real Data, except that interpolation does not make sense for integer grid codes.
If Integer Grid Codes are being used to assign Model Properties, such as soil profiles or time series, then new sub-branches will appear in the data tree corresponding to the number of unique Integer Grid Codes in the .dfs2 file.
Uniform Value
A Uniform, global value means that all the grid cells in the model will have the same value. Thus, all cells would belong to the same zone.
Grid File (.dfs2)
If the Integer Code is defined using a grid file, then the Integer Code is defined on a grid. This grid may be different than the numerical model grid. However, the grids must be subsets of one another. That is, the Integer Code grid and the model grid must be aligned with one another and the Integer Code grid or the model grid must contain an even multiple of the other grid’s cells. For example, if the Integer Code grid was two times finer, then every model grid cell must contain exactly four Integer Codes.
Normally, the Integer Code will be assigned to the model grid based on the most prevalent Integer Code in the cell. However, this can lead to problems when the a particular code is both infrequent and widely dispersed. For example, if a model area contained many small wetland areas that were much smaller than a grid cell.
For this reason, a bookkeeping count is kept of the assignments to reduce any bias in the assignment of Integer Codes and ensure that less frequently occurring Integer Codes will be represented in the resulting model grid. For example, if their were two different Integer Codes, A and B, used in the model and A always occurred more frequently in each model cell, the bookkeeping count would ensure that B would actually be assigned to some of the model cells. The final frequency of occurrence of the Integer Codes in the model cells would reflect the underlying frequency of occurrence of the Integer Codes. That is, if A occurred twice as often as B, the model grid would also contain twice as many A’s as B’s.
Thus, in our widely dispersed wetland example, if every model grid cell contained 9 Integer Codes for Land Use, and 1/9 of the Land Use grid codes were for wetlands, then every ninth Model Cell would be assigned a Land Use grid code for wetlands.
In the current version, only some of the parameters are set up to accept .shp file polygons. Currently, .shp file polygons are only allowed in:
· Model Domain and Grid (V1 p. 224)
· Precipitation Rate (V1 p. 230)
· Reference Evapotranspiration (V1 p. 234)
· UZ Soil Profile Definitions (V1 p. 287),
· SZ Internal boundary conditions (V1 p. 321), and
· Horizontal Extent (V1 p. 349) of SZ Lenses.
Note: The Horizontal Extent (V1 p. 349) of SZ Lenses accepts polygons, but the dialogue is still set up for point/line .shp files and an error is given in the Data Verification window.
Model grid codes are assigned based in which polygon the centre of the cell is located in.
