Vector geoprocessing ==================== .. only:: html .. contents:: :local: :depth: 1 .. _gdalbuffervectors: Buffer vectors -------------- Create buffers around the features of a vector layer. Parameters .......... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Input layer** - ``INPUT`` - [vector: any] - The input vector layer * - **Geometry column name** - ``GEOMETRY`` - [string] Default: 'geometry' - The name of the input layer geometry column to use * - **Buffer distance** - ``DISTANCE`` - [number] Default: 10.0 - Minimum: 0.0 * - **Dissolve by attribute** Optional - ``FIELD`` - [tablefield: any] Default: None - Field to use for dissolving * - **Dissolve results** - ``DISSOLVE`` - [boolean] Default: False - If set, the result is dissolved. If no field is set for dissolving, all the buffers are dissolved into one feature. * - **Produce one feature for each geometry in any kind of geometry collection in the source file** - ``EXPLODE_COLLECTIONS`` - [boolean] Default: False - * - **Additional creation options** (optional) - ``OPTIONS`` - [string] Default: '' (no additional options) - Additional GDAL creation options. * - **Buffer** - ``OUTPUT`` - [vector: polygon] Default: ``[Save to temporary file]`` - Specify the output buffer layer. One of: * Save to a Temporary File * Save to File... The file encoding can also be changed here. Outputs ....... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Buffer** - ``OUTPUT`` - [vector: polygon] - The output buffer layer .. _gdalclipvectorbyextent: Clip vector by extent ---------------------- Clips any OGR-supported vector file to a given extent. This algorithm is derived from the `ogr2ogr utility `_ . Parameters .......... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Input layer** - ``INPUT`` - [vector: any] - The input vector layer * - **Clip extent** - ``EXTENT`` - [extent] - Defines the bounding box that should be used for the output vector file. It has to be defined in target CRS coordinates. * - **Additional creation options** (optional) - ``OPTIONS`` - [string] Default: '' (no additional options) - Additional GDAL creation options. * - **Clipped (extent)** - ``OUTPUT`` - [same as input] Default: ``[Save to temporary file]`` - Specify the output (clipped) layer. One of: * Save to a Temporary File * Save to File... The file encoding can also be changed here. Outputs ....... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Clipped (extent)** - ``OUTPUT`` - [vector: any] - The output (clipped) layer. The default format is "ESRI Shapefile". .. _gdalclipvectorbymasklayer: Clip vector by mask layer ------------------------- Clips any OGR-supported vector layer by a mask polygon layer. This algorithm is derived from the `ogr2ogr utility `_ . Parameters .......... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Input layer** - ``INPUT`` - [vector: any] - The input vector layer * - **Mask layer** - ``MASK`` - [vector: polygon] - Layer to be used as clipping extent for the input vector layer. * - **Additional creation options** (optional) - ``OPTIONS`` - [string] Default: '' (no additional options) - Additional GDAL creation options. * - **Clipped (mask)** - ``OUTPUT`` - [same as input] Default: ``[Save to temporary file]`` - The output (masked) layer. One of: * Save to a Temporary File * Save to File... The file encoding can also be changed here. Outputs ....... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Clipped (mask)** - ``OUTPUT`` - [vector: any] - The output (masked) layer. The default format is "ESRI Shapefile". .. _gdaldissolve: Dissolve -------- Dissolve (combine) geometries that have the same value for a given attribute / field. The output geometries are multipart. Parameters .......... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Input layer** - ``INPUT`` - [vector: any] - The input layer to dissolve * - **Dissolve field** (optional) - ``FIELD`` - [tablefield: any] - The field of the input layer to use for dissolving * - **Geometry column name** - ``GEOMETRY`` - [string] Default: 'geometry' - The name of the input layer geometry column to use for dissolving. * - **Produce one feature for each geometry in any kind of geometry collection in the source file** - ``EXPLODE_COLLECTIONS`` - [boolean] Default: False - Produce one feature for each geometry in any kind of geometry collection in the source file * - **Keep input attributes** - ``KEEP_ATTRIBUTES`` - [boolean] Default: False - Keep all attributes from the input layer * - **Count dissolved features** - ``COUNT_FEATURES`` - [boolean] Default: False - Count the dissolved features and include it in the output layer. * - **Compute area and perimeter of dissolved features** - ``COMPUTE_AREA`` - [boolean] Default: False - Compute the area and perimeter of dissolved features and include them in the output layer * - **Compute min/max/sum/mean for attribute** - ``COMPUTE_STATISTICS`` - [boolean] Default: False - Calculate statistics (min, max, sum and mean) for the numeric attribute specified and include them in the output layer * - **Numeric attribute to calculate statistics on** (optional) - ``STATISTICS_ATTRIBUTE`` - [tablefield: numeric] - The numeric attribute to calculate statistics on * - **Additional creation options** (optional) - ``OPTIONS`` - [string] Default: '' (no additional options) - Additional GDAL creation options. * - **Dissolved** - ``OUTPUT`` - [same as input] Default: ``[Save to temporary file]`` - Specify the output layer. One of: * Save to a Temporary File * Save to File... The file encoding can also be changed here. Outputs ....... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Dissolved** - ``OUTPUT`` - [vector: any] - The output multipart geometry layer (with dissolved geometries) .. _gdaloffsetcurve: Offset curve ------------ Offsets lines by a specified distance. Positive distances will offset lines to the left, and negative distances will offset them to the right. Parameters .......... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Input layer** - ``INPUT`` - [vector: line] - The input line layer * - **Geometry column name** - ``GEOMETRY`` - [string] Default: 'geometry' - The name of the input layer geometry column to use * - **Offset distance (left-sided: positive, right-sided: negative)** - ``DISTANCE`` - [number] Default: 10.0 - * - **Additional creation options** (optional) - ``OPTIONS`` - [string] Default: '' (no additional options) - Additional GDAL creation options. * - **Offset curve** - ``OUTPUT`` - [vector: line] Default: ``[Save to temporary file]`` - Specify the output line layer. One of: * Save to a Temporary File * Save to File... The file encoding can also be changed here. Outputs ....... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Offset curve** - ``OUTPUT`` - [vector: line] - The output offset curve layer .. _gdalonesidebuffer: One side buffer --------------- Creates a buffer on one side (right or left) of the lines in a line vector layer. Parameters .......... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Input layer** - ``INPUT`` - [vector: line] - The input line layer * - **Geometry column name** - ``GEOMETRY`` - [string] Default: 'geometry' - The name of the input layer geometry column to use * - **Buffer distance** - ``DISTANCE`` - [number] Default: 10.0 - * - **Buffer side** - ``BUFFER_SIDE`` - [enumeration] Default: 0 - One of: * 0 --- Right * 1 --- Left * - **Dissolve by attribute** Optional - ``FIELD`` - [tablefield: any] Default: None - Field to use for dissolving * - **Dissolve all results** - ``DISSOLVE`` - [boolean] Default: False - If set, the result is dissolved. If no field is set for dissolving, all the buffers are dissolved into one feature. * - **Produce one feature for each geometry in any kind of geometry collection in the source file** - ``EXPLODE_COLLECTIONS`` - [boolean] Default: False - * - **Additional creation options** (optional) - ``OPTIONS`` - [string] Default: '' (no additional options) - Additional GDAL creation options. * - **One-sided buffer** - ``OUTPUT`` - [vector: polygon] Default: ``[Save to temporary file]`` - Specify the output buffer layer. One of: * Save to a Temporary File * Save to File... The file encoding can also be changed here. Outputs ....... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **One-sided buffer** - ``OUTPUT`` - [vector: polygon] - The output buffer layer .. _gdalpointsalonglines: Points along lines ------------------ Generates a point on each line of a line vector layer at a distance from start. The distance is provided as a fraction of the line length. Parameters .......... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Input layer** - ``INPUT`` - [vector: line] - The input line layer * - **Geometry column name** - ``GEOMETRY`` - [string] Default: 'geometry' - The name of the input layer geometry column to use * - **Distance from line start represented as a fraction of line length** - ``DISTANCE`` - [number] Default: 0.5 (middle of the line) - * - **Additional creation options** (optional) - ``OPTIONS`` - [string] Default: '' (no additional options) - Additional GDAL creation options. * - **Points along line** - ``OUTPUT`` - [vector: point] Default: ``[Save to temporary file]`` - Specify the output point layer. One of: * Save to a Temporary File * Save to File... The file encoding can also be changed here. Outputs ....... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Points along line** - ``OUTPUT`` - [vector: point] - The output point layer