The Aggregate Map operation can be directly executed by typing one of the following expressions on the command line of the Main window:
|
OUTMAP |
= |
MapAggregateAggFnc(InputMapName, Groupfactor, group) |
|
OUTMAP |
= |
MapAggregateAggFnc(InputMapName, Groupfactor, nogroup) |
|
OUTMAP |
= |
MapAggregateAggFnc(InputMapName, Groupfactor, group, RowOffset, ColOffset) |
|
OUTMAP |
= |
MapAggregateAggFnc(InputMapName, Groupfactor, nogroup, RowOffset, ColOffset) |
|
OUTMAP |
= |
MapAggregateAggFnc(InputMapName, Groupfactor, group, NewGeoref) |
|
OUTMAP |
= |
MapAggregateAggFnc(InputMapName, Groupfactor, group, RowOffset, ColOffset, NewGeoref) |
where:
|
OUTMAP |
is the name of the output raster map. |
|
MapAggregate |
is the first part of the command to start the Aggregate Map operation. |
|
AggFnc |
is the second part of the command to start the Aggregate Map operation. Type an aggregation function directly after MapAggregate (no spaces allowed): Avg | Max | Med | Min | Prd | Std | Sum If no aggregation function is specified on the command line, the operation will use the pixel in the upper left corner of each block of input pixels as output value. |
|
InputMapName |
is the name of the input raster map. |
|
Groupfactor |
is a value for the size of the blocks of input pixels to be aggregated; group factor 4 means that the aggregation is performed on each block of 4 x 4 input pixels (integer >= 2). |
|
group |
is the parameter to indicate to group the aggregated value into one output pixel. |
|
nogroup |
is the parameter to indicate to use the georeference of the input map for the output map. In this case, each output aggregation value is assigned to all output pixels that correspond to the blocks of input pixels. |
|
RowOffset |
is an optional parameter to skip the specified number of lines at the top of the input map, i.e. the aggregation will start at line RowOffset+1. |
|
ColOffset |
is an optional parameter to skip the specified number of columns at the left of the input map, i.e. the aggregation will start at ColOffset+1. |
|
NewGeoref |
is an optional parameter to specify a name for the output georeference; if not specified, the output georeference will obtain the same name as the output map. |
All Aggregation functions work on input value maps; the Count, Median and Predominant aggregation functions also work on maps of other domain types.
To specify the domain and value range of the output map, you can use curly brackets after the output map name, for instance:
OUTMAP{dom=MyDom} = expression
OUTMAP{dom=MyDom;vr=min:max:prec} = expression
For more information, see Appendices : ILWIS expressions.
Tip: To use this operation on all raster maps in a map list, see Aggregate map : command line (2).
When the definition symbol = is used, a dependent output map is created; when the assignment symbol := is used, the dependency link is immediately broken after the output map has been calculated. Further, when the Group option is used, a georeference factor is created with the same name as the output map, unless you specify a new georeference name yourself.
See also: