Geoprocessing: Convex Hulls: Creates the smallest possible convex polygon enclosing a group of objects. Procedure: 1. Create a point layer and add atleast 3 points. 2. Vector>Geo Processing Tools>Convex Hull(s) 3. Select point layer in the input vector layer. Browse to specify path and name of output file. Press OK Buffers: Definition: Creates an equal zone around specific features at a specified distance. Procedure: 1. Create a line layer. 2. Vector>Geo Processing Tools>Buffer(s) 3. Select that line layer. type 10 in segments to approximate. Give buffer distance of 0.1. Specify output file and press OK. Intersect: Definition: Creates new layer based on the area of overlap of two layers. Procedure: 1. Create two polygons in two separate layers. 2. Vector>Geo Processing Tools>Intersect 3. Select the input layer and intersect layer. Browse to specify output layer and press OK. Union: Definition: Merge two layers together into one while preserving features and attributes of both. Procedure: 1. Create two polygons in two separate layers. 2. Vector>Geo Processing Tools>Union 3. Select the input layer and union layer. Browse to specify output layer and press OK. Symmetrical Difference: Definition: Creates new layer based on areas of two layers that do not overlap. Procedure: 1. Create two polygons in two separate layers. 2. Vector>Geo Processing Tools>Symmetrical Difference 3. Select the input layer and Difference layer. Browse to specify output layer and press OK. Clip: Definition: Cuts a layer based on the boundaries of another layer. Procedure: 1. Create two polygons in two separate layers. 2. Vector>Geo Processing Tools>Clip 3. Select the input layer and Clip layer. Browse to specify output layer and press OK. 1
Definition and procedure for geoprocessing in qgis. Including various commands in geoprocessing.
Citation preview
Geoprocessing:
Convex Hulls:Creates the smallest possible convex polygon
enclosing a group of objects.Procedure: 1. Create a point layer and
add atleast 3 points.2. Vector>Geo Processing Tools>Convex
Hull(s)3. Select point layer in the input vector layer. Browse to
specify path and name of output file. Press OK
Buffers: Definition: Creates an equal zone around specific
features at a specified distance.Procedure: 1. Create a line
layer.2. Vector>Geo Processing Tools>Buffer(s)3. Select that
line layer. type 10 in segments to approximate. Give buffer
distance of 0.1. Specify output file and press OK.
Intersect:Definition: Creates new layer based on the area of
overlap of two layers.Procedure:1. Create two polygons in two
separate layers.2. Vector>Geo Processing Tools>Intersect3.
Select the input layer and intersect layer. Browse to specify
output layer and press OK.
Union:Definition: Merge two layers together into one while
preserving features and attributes of both.Procedure: 1. Create two
polygons in two separate layers.2. Vector>Geo Processing
Tools>Union3. Select the input layer and union layer. Browse to
specify output layer and press OK.
Symmetrical Difference: Definition: Creates new layer based on
areas of two layers that do not overlap.Procedure:1. Create two
polygons in two separate layers.2. Vector>Geo Processing
Tools>Symmetrical Difference3. Select the input layer and
Difference layer. Browse to specify output layer and press OK.
Clip: Definition: Cuts a layer based on the boundaries of
another layer.Procedure:1. Create two polygons in two separate
layers.2. Vector>Geo Processing Tools>Clip3. Select the input
layer and Clip layer. Browse to specify output layer and press
OK.
1
Difference: Definition: Subtracts areas of one layer based on
the overlap of another layer.Procedure: 1. Create two polygons in
two separate layers.2. Vector>Geo Processing
Tools>Symmetrical Difference3. Select the input layer and
Difference layer. Browse to specify output layer and press OK.
Dissolve: Definition: Merges features within a single layer
based on common attributes in the attribute table.Procedure: 1.
Create two polygons in two separate layers.2. Vector>Geo
Processing Tools>Dissolve3. Select the input layer and dissolve
field. Browse to specify output layer and press OK.
Eliminate Sliver Polygons:Definition: Merges selected features
with the neighboring polygon with the largest area or largest
common boundary.Procedure:1. Create two polygons in a new single
layer with overlapping boundaries.2. Select the main polygon then
Vector>Geo Processing Tools>Sliver Polygons3. Provide the new
layer in the input vector layer. Select area option and check add
result to canvas. Press OK.
Reference:1. User Manual of QGIS2. Geoprocessing in QGIS from
Slideshare.com
