Changes between Version 5 and Version 6 of LayerAlgebra

Timestamp:

Aug 10, 2012, 12:31:36 AM (12 years ago)

Author:

Ari Jolma

Comment:

--

LayerAlgebra

@@ -7 +7 @@
 The GDAL layer algebra is implemented as methods in the OGRLayer class. The C API is similar to the methods except that the object itself is the first argument and that the layer pointers are validated. In the Swig bindings these are again methods in Layer class.
 
-Each method works on the object itself (the "input" layer) and a second operand (the "method" layer) and produces a result layer. The result layer needs to exist when calling any of these methods (this may not be the case in bindings languages).
+Each method works on the object itself (the "input" layer) and a second operand (the "method" layer) and produces a result layer. The result layer needs to exist when calling any of these methods (this may not be the case in bindings languages necessarily).
 
 The schema of the result layer can be user-defined (the layer definition of the result layer has one or more fields) or it can be created by the method. If created, it will be either the schema of the input layer or the combined schema of input and method layers, depending on the method.
@@ -35 +35 @@
 == !SymDifference ==
 
+A symmetric difference is a set of features, which represent areas that are in either of the operand layers.
+
+[[Image(SymDifference.jpg)]]
+
+'''Figure''' An example of the symmetric difference (c) of two layers (a and b). The feature 4 of the result layer is selected.
+
 == Identity ==