Graphics Reference
In-Depth Information
symbol_male = ...
symbol_female = ...
categories = []
categories.append(QgsRendererCategoryV2("M", symbol_male,
"Male"))
categories.append(QgsRendererCategoryV2("F", symbol_female,
"Female"))
renderer = QgsCategorizedSymbolRendererV2("", categories)
renderer.setClassAttribute("GENDER")
layer.setRendererV2(renderer)
Notice that the
QgsRendererCategoryV2
constructor takes three parameters: the de-
sired value, the symbol used, and the label used to describe that category.
Finally, to use a graduated symbol renderer, you define a list of
qgis.core.QgsRendererRangeV2
objects and then use that to create your render-
er. For example:
symbol1 = ...
symbol2 = ...
ranges = []
ranges.append(QgsRendererRangeV2(0, 10, symbol1, "Range 1"))
ranges.append(QgsRendererRange(11, 20, symbol2, "Range 2"))
renderer = QgsGraduatedSymbolRendererV2("", ranges)
renderer.setClassAttribute("FIELD")
layer.setRendererV2(renderer)
Accessing vector data
In addition to displaying the contents of a vector layer within a map, you can use Python
to directly access the underlying data. This can be done using the data provider's
getFeatures()
method. For example, to iterate over all the features within the layer,
you can do the following:
