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The GREDUCE Procedure |
Requirements: | An input map data set is required. |
PROC GREDUCE <option(s)>; |
option(s) can be one or more options from any or all of the following categories:
data set options:
DATA=input-map-data-set | |
OUT=output-map-data-set |
level options:
E1=min-distance | |
E2=min-distance | |
E3=min-distance | |
E4=min-distance | |
E5=min-distance | |
N1=max-points | |
N2=max-points | |
N3=max-points | |
N4=max-points | |
N5=max-points |
Options |
See also: | About the Input Map Data Set and SAS Data Sets |
Express min-distance values in the units for the coordinate system of the input map data set. For example, if the input map data set contains coordinates that are expressed in radians, express the min-distance values in radians.
Specify the En= values in decreasing order. For example, the E2= value should be less than the E1= value and so on.
Specify the Nn= values in increasing order. For example, the N2= value should be greater than or equal to the N1= value and so on.
By default, if you omit Nn= and En = , the GREDUCE procedure calculates values for the five Nn = parameters using this formula:
Here N_{max} is the maximum number of points in any unit area in the input map data set. However, the restriction that the number of points for any level cannot be less than the number of points in level 0 still applies.
By default, the GREDUCE procedure names the new data set that uses the DATAn naming convention. That is, the procedure uses the name WORK.DATAn, where n is the next unused number in sequence. Thus, the first automatically named data set is DATA1, the second is DATA2, and so on.
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