The Raster Calculator provides several additional commands introduced to improve the functionality of the Raster Calculator. Each of the additional functions are described below. The commands undertake specific tasks using a range of supplied parameters. These parameters (shown in red) may take the form of specific values or alternatively, user variables or project variables that contain data of an appropriate data type. In addition to the functions listed below, almost all CSTalk Macro commands/procedures and variables can also be used with the Raster Calculator.
Project Variables
The following project variables relate to the Raster Calculator variable category. They refer to variables that can be utilised within the raster calculator in order to effectively carry out operations on pixels within the DEM. The main use of these variables is to expedite the iteration through DEM pixels by referring to an individual row and column location.
These project variables must all be prefixed with %RasterCalculator.
Row[i] |
Refers to the pixel at the given row integer |
integer |
|
Column[j] |
Refers to the pixel at the given column integer |
integer |
|
LookupTable1(&Var,PATH.csv,Value,Col,Ans_Col)
The LookupTable1 command is used to assign values from a lookup table to a new array (&Var). Path.csv is the full path and file name of the lookup table (in CSV file format) and Value is the name of an existing raster grid layer or GIS layer attribute where values will be extracted. Each value will be read from the GIS/Grid layer and the program will look for an a corresponding value in the Col column of the CSV lookup table. When the value is found, the program will extract the corresponding value from the Ans_col column and will assign this value to the &Var array.
Parameter |
Description |
Accepted Values / Data Type |
&Var |
Name of the variable array to which the lookup table values will be assigned |
Decimal, integer or text |
PATH.csv |
Full path and filename of the lookup table (in CSV file format) |
String |
Value |
Name of an existing raster grid layer or GIS layer attribute where values will be extracted and searched for in 'Col' column of lookup table |
Decimal, integer or text |
Col |
Column in lookup table containing values corresponding to parameter values contained in 'Value' GIS attibute or grid layer |
Integer |
Ans_Col |
Column in lookup table containing values to be written to '&Var' |
Integer |
Eg., LookupTable1(&A,C:\Bathurst_LU.csv,&ARI,1,2)
WriteValue(#Grid#,Value)
The WriteValue function is used to populate each pixel in a raster grid (#Grid#) with a Value. You must be sure that the Value data type and the grid cell type (decimal, integer or text) are compatible.
Parameter |
Description |
Accepted Values / Data Type |
#Grid# |
Name of raster grid to which Value is to be written. Please note Grid name must be enclosed in # # symbols |
String |
Value |
The value (either numerical or text) to be written to the grid |
Decimal, integer or text |
Eg., WriteValue(#Rainfall_Intensity#,&RI)
Copy(&Var,Text,Index,Count)
The Copy command will copy one or more characters from a string to a new variable (&Var) based on a user-specified index. Text is a string containing one or more characters. This may be a string from an array or a raster grid layer. Index is the index of the first character that is to be extracted and Count is the number of characters that are to be extracted.
Parameter |
Description |
Accepted Values / Data Type |
&Var |
Name of the variable to which the requested characters will be copied to |
String |
Text |
The string from which the characters will be extracted. This can be sourced from an array or a string grid layer. |
String |
Index |
Index of the first character in the Text string that is to be extracted. For example in the string "Cat", the letter "a" would have an index of 2. |
Integer |
Count |
The number of characters that are to be extracted. For example, if we were to extract 2 characters from the string "Cat", starting at index 2 we would end up with "at". "at would be written to the &Var variable |
Integer |
Eg., Copy(&HydG1,#Hyd_Group_Raw#,1,1)
