By specifying a mask, you can search for points, segments or polygons with a certain class name, ID or value. A mask is in fact a simple query to find (retrieve), display or use only those points, segments or polygons in a map that have certain class names, identifiers or values. A mask contains one or more search strings in which wild cards, asterisks (*) and question marks (?), are allowed. You can enter as many search strings in a mask as you like; separate the strings by commas. A mask can be specified in
Display Options dialog boxes of vector maps and in several Vector Operations. For more information, see How to use masks.
Mask syntax:
- search strings in a mask are compared with the classes, IDs or values of the domain of a map; when a map uses a class or ID domain and the classes or IDs have codes, the mask works on the codes and on the names and on the combination of codes and names,
- to find/retrieve one specific class name, identifier or value: type that class name, ID or identifier in the mask,
- to find/retrieve multiple class names, identifiers or values: separate the different class names, identifiers or values in the mask by commas (it does not matter whether you use spaces before or after a comma)
- you can use asterisks as wild cards to replace zero or more characters in class names, IDs or values, for example road*,riv* or 1*,2*,3* , or even *25,*50,*75,*00, or A*b*,D*g*
- you can use question marks as wild cards to replace single characters in class names, identifiers or values, for example Ab?,D?,Gl? or ?p,??i, or A*b??,D*g??
- in a dialog box, you should not use quotes around class names, identifiers or values,
- on the command line, you must use double quotes around the complete mask.