Provides functionality for manipulation of vector data. The data can be in-memory or file based.
InaSAFE representation of vector data.
Only used if geometry is provided as a numeric array, if None, WGS84 geographic is assumed.
(see note below).
Valid options are ‘point’, ‘line’, ‘polygon’ or the ogr types: 1, 2, 3. If None, a geometry_type will be inferred from the data.
name: Optional name for layer. If None, basename is used.
layer. When the layer is stored, these keywords will be written into an associated file with extension ‘.keywords’.
Keywords can for example be used to display text about the layer in an application.
should be styled. See impact_functions/styles.py for examples.
table name in case of sqlite etc.) to load. Only applicable to those dataformats supporting more than one layer in the data file.
If data is a filename, all other arguments are ignored as they will be inferred from the file.
The geometry type will be inferred from the dimensions of geometry. If each entry is one set of coordinates the type will be ogr.wkbPoint, if it is an array of coordinates the type will be ogr.wkbPolygon.
To cast array entries as lines set geometry_type explicitly to ‘line’ in the call to Vector. Otherwise, they will default to polygons.
Each polygon or line feature take the form of an Nx2 array representing vertices where line segments are joined.
If polygons have holes, their geometry must be passed in as a list of polygon geometry objects (as defined in module geometry.py)
Return vector layer data as qgis QgsVectorLayer.
Return copy of vector layer
This copy will be equal to self in the sense defined by __eq__
Get available attribute names.
These are the ones that can be used with get_data
Get bounding box coordinates for vector layer.
Format is [West, South, East, North]
Get vector attributes.
A list where each entry is a dictionary of attributes for one feature.
Data is returned as a list where each entry is a dictionary of attributes for one feature. Entries in get_geometry() and get_data() are related as 1-to-1
If optional argument attribute is specified and a valid name, then the list of values for that attribute is returned.
If optional argument index is specified on the that value will be returned. Any value of index is ignored if attribute is None.
If optional argument copy is True and all attributes are requested, a copy will be returned. Otherwise a pointer to the data is returned.
Get min and max values from specified attribute
|Parameters:||attribute (str) – Specify an attribute name of which to return data.|
|Returns:||minimum and maximum attribute values|
Return geometry for vector layer.
Depending on the feature type, geometry is:
geometry type output type point list of 2x1 array of longitudes and latitudes) line list of arrays of coordinates polygon list of arrays of coordinates
Optional boolean argument as_geometry_objects will change the return value to a list of geometry objects rather than a list of arrays. This currently only applies to polygon geometries
A list of geometry objects or arrays.
Return geometry name for vector layer
Return geometry type for vector layer
Get top N features
New vector layer with selected features
Check whether this is a line
Check whether this is multipolygon
Check whether this is a point
Check whether this is a polygon
Read and unpack vector data.
It is assumed that the file contains only one layer with the pertinent features. Further it is assumed for the moment that all geometries are points.
Examples are at * danieljlewis.org/files/2010/09/basicpythonmap.pdf * http://invisibleroads.com/tutorials/gdal-shapefile-points-save.html * http://www.packtpub.com/article/geospatial-data-python-geometry
Limitation of the Shapefile are documented in http://resources.esri.com/help/9.3/ArcGISDesktop/com/Gp_ToolRef/ geoprocessing_tool_reference/ geoprocessing_considerations_for_shapefile_output.htm
|Parameters:||filename (str) – a fully qualified location to the file|
Read and unpack vector data from qgis layer QgsVectorLayer.
Save vector data to file
Shp limitation, if attribute names are longer than 10 characters they will be truncated. This is due to limitations in the shp file driver and has to be done here since gdal v1.7 onwards has changed its handling of this issue: http://www.gdal.org/ogr/drv_shapefile.html
For this reason we recommend writing to spatialite.
Convert line vector data to point vector data
Vector layer with point data and the same attributes as V
Convert polygon vector data to point vector data
|Parameters:||V (Vector) – Vector layer with polygon data|
|Returns:||Vector layer with point data and the same attributes as V|