ogr_layer_algebra - Performs various Vector layer algebraic
operations
New in version 3.6.
ogr_layer_algebra.py Union|Intersection|SymDifference|Identity|Update|Clip|Erase
-input_ds name [-input_lyr name]
-method_ds [-method_lyr name]
-output_ds name [-output_lyr name] [-overwrite]
[-opt NAME=VALUE]*
[-f format_name] [-dsco NAME=VALUE]* [-lco NAME=VALUE]*
[-input_fields NONE|ALL|fld1,fl2,...fldN] [-method_fields NONE|ALL|fld1,fl2,...fldN]
[-nlt geom_type] [-a_srs srs_def]
The ogr_layer_algebra.py provides a command line utility to
perform various vector layer algebraic operations. The utility takes a
vector input source , a method source and generates the output of the
operation in the specified output file
- <mode>
- Where <mode> is one of the seven available modes:
- •
- Union
A union is a set of features, which represent areas that
are in either of the operand layers.
- •
- Intersection
An intersection is a set of features, which represent the
common areas of two layers.
- •
- SymDifference
A symmetric difference is a set of features, which
represent areas that are in operand layers but which do not intersect.
- •
- Identity
The identity method identifies features in the input
layer with features in the method layer possibly splitting features into
several features. By default the result layer has attributes from both operand
layers.
- •
- Update
The update method creates a layer, which add features
into the input layer from the method layer possibly cutting features in the
input layer. By default the result layer has attributes only from the input
layer.
- •
- Clip
The clip method creates a layer, which has features from
the input layer clipped to the areas of the features in the method layer. By
default the result layer has attributes of the input layer.
- •
- Erase
The erase method creates a layer, which has features from
the input layer whose areas are erased by the features in the method layer. By
default the result layer has attributes of the input layer.
- -input_ds
<path>
- Input data set path for the operation to be performed. For operations
involving 2 datasets, this is one of the dataset.
- -input_lyr
<name>
- Layer name of the input_ds for which the operations have to be
performed ( Optional )
- -method_ds
<path>
- Method data set path for the operation to be performed. This is usually
the conditional data set supplied to the operation ( ex: clip , erase ,
update ) This is the Second data set in the operation ( ex : Union,
Intersection , SymDifference )
- -method_lyr
<name>
- Layer name of the method_ds for which the operations have to be
performed ( Optional )
- -output_ds
<path>
- Output data set path for writing the result of the operations performed by
ogr_layer_algebra
- -overwrite
- Indicates whether the output_ds have to be overwritten with the
generated result of ogr_layer_algebra
- -opt
<NAME=VALUE>
- Attributes for which the operation has to run on input_ds and
method_ds
- -f
<format_name>
- Select the output format.If not specified, the format is guessed from the
extension (previously was ESRI Shapefile). Use the short format name
- -nlt
<geom_type>
- Define the geometry type for the created layer. One of NONE, GEOMETRY,
POINT, LINESTRING, POLYGON, GEOMETRYCOLLECTION, MULTIPOINT, MULTIPOLYGON,
GEOMETRY25D, POINT25D, LINESTRING25D, POLYGON25D, GEOMETRYCOLLECTION25D,
MULTIPOINT25D, MULTIPOLYGON25D.
- -a_srs
<srs_def>
- Assign an output SRS, but without reprojecting
The coordinate reference systems that can be passed are
anything supported by the OGRSpatialReference.SetFromUserInput() call,
which includes EPSG Projected, Geographic or Compound CRS (i.e.
EPSG:4296), a well known text (WKT) CRS definition, PROJ.4 declarations,
or the name of a .prj file containing a WKT CRS definition.