[GIS] Get extents of vector shape features in PyQGIS

extentspyqgis

i am just wondering if it is possible to iterate through vector features and return the extent per feature without clipping the vector shape?

The code looks like this and comes from the PyQgis-Documentation. How can i return the extent of every vector feature in a loop.

provider = vector.dataProvider()
            feat = QgsFeature()
            allAttrs = provider.attributeIndexes()
            provider.select(allAttrs)
            while provider.nextFeature(feat):
                geom = feat.geometry()
                # --> return extent or (xmin,ymin,xmax,ymax) ?

Best Answer

how about...

provider = vector.dataProvider()
        feat = QgsFeature()
        allAttrs = provider.attributeIndexes()
        provider.select(allAttrs)
        while provider.nextFeature(feat):
            geom = feat.geometry()
            rect = geom.boundingBox()  #get bounding box as QgsRectangle

Related Solutions

[GIS] Understanding use of extents in ArcPy

Found my answer, was just a confusion on my part. Obviously a lot of brain work and ArcGIS help was involved, so if someone cares to explain further what exactly I did, it may help to clarify things for others with the same confusions I had.

For those interested, here is the solution I came up with:

#Define Geodatabase and workspace
    #gdb = r"F:\...\####.gdb"
    env.workspace = gdb
    env.scratchworkspace = gdb
    # Set extent
    extent = arcpy.Extent(XMIN,YMIN,XMAX,YMAX)
#List available Feature Classes in a List
    def FCs_in_GDB(gdb):
        try:
            fcs = []
            for fds in arcpy.ListDatasets('','feature') + ['']:
                for fc in arcpy.ListFeatureClasses('','',fds):
                    fcs.append(os.path.join(fds, fc))
            return fcs
        except:
            print ("An Error has occured in FCs_in_GDB().")
    fc_list = FCs_in_GDB(gdb)
#Process Describe() filter on Count function
    for fc in fc_list:
        try:
            name = arcpy.Describe(fc).name
            x = arcpy.Describe(fc).extent
            overlaps = x.overlaps(extent)
            contains = x.contains(extent)
            within = x.within(extent)
            if overlaps==True or contains==True or within==True:
                count = arcpy.GetCount_management(fc)
        except:
            print ("An Error has occurred in fc_list().")

PyQGIS – Extent Parameter in GDAL Processing Rasterize

You may try to manage the extent with the following lines:

extent = pointsLayer.extent()
xmin = extent.xMinimum()
xmax = extent.xMaximum()
ymin = extent.yMinimum()
ymax = extent.yMaximum()

Once you have done this, you may insert the extent parameter in this way:

first = processing.runalg("gdalogr:rasterize", {"INPUT":tempout, "FIELD":"serp_id", "DIMENSIONS":1, 
        "WIDTH": resGrid, "HEIGHT":resGrid, "TFW":False, "RTYPE":2, 
        "NO_DATA":0, "RAST_EXT":"%f,%f,%f,%f" %(xmin, xmax, ymin, ymax), "BIGTIFF": 2, "OUTPUT":None})

Best Answer

Related Solutions

[GIS] Understanding use of extents in ArcPy

PyQGIS – Extent Parameter in GDAL Processing Rasterize

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