Vector Processing Plugin
The Vector Processing plugin contains several processing algorithms applied to vector data:
-
Buffer - The Buffer
is a spatial operation that can be applied to a single layer.
The buffer zone may be defined as an area generated around
an object with a predetermined distance.
-
Difference - The Difference
is spatial operation and needs two layers.
This operation creates a new layer composed of the difference between geometries of two layers.
-
Dissolve - The Dissolve
operation is applied to a single layer and a chosen group of attributes that can be summarized. The idea is
to generate a new layer with summarized information. The geometries of
each group are dissolved through the UNION
spatial operation and the attributes can be summarized using of the
dissolve operation:
sum,
count,
maximum,
minimum,
average
and so on.
-
Geometric Operations - The Geometric Operations
available are
Centroid, Convex Hull and
Minimum Bounding Rectangle (MBR).
These operations return a new geometry as a result. In addition there is also basic operations such as
Perimeter, Area and
Lenght,
returning only a numeric value for each geometry.
-
Identity - The Identity
is spatial operation and is needs two layers.
This operation creates a new layer composed of the difference and the intersection between geometries of the two layers.
-
Intersection - The Intersection
is spatial operation and needs two layers. The first one containg polygons
that form a clipping mask, and the second one (with any kind of representation
ex. polygons, lines, points) that will be clipped. The result is a new layer
formed by the objects of the second layer in the intersection with the clipping mask.
-
Line to Polygon - The Line to Polygon
operation is applied to a single layer composed of lines.
This operation creates a new layer where all closed lines are transformed in polygons.
-
Merge - The Merge
is spatial operation and needs two layers.
This operation makes the insertion of a layer data in another layer
-
Polygon to Line - The Polygon to Line
operation is applied to a single layer composed of polygons.
This operation creates a new layer where all polygons are trasnformed in closed lines.
-
Union - The Union
is a spatial operation and needs two layers.
This operation makes an union between two layer considering the intersection.
NOTE: To save the result in PostGIS, the SRID of the output layer (inherited from input layer)
should be one of the SRID´s listed in PostGIS Spatial Refecence
System table. The message below will be
displayed when the SRID is not recognized by PostGIS:
"PostGIS
doens't recognize this projection. Please, reproject your data to a
correct one. Or save your result as Vector File, and afterwards use
Exchange to put the result in PGIS, changing the USER SRID to a valid
one."