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.
- Check
geometry validity - The Check Geometry Validity It is used to
identify/visualize invalid geometries, and fix them.
- 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.
- Make
Valid Operation - Used to fix all invalid geometries.
- 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.
- Register
- Register
vector data using tie-points.
- 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 SRIDīs 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."