In the QgsDistanceArea
object, PyQGIS has excellent capabilities for measuring the distance. We'll use this object for several recipes, starting with measuring the distance between two points.
If you don't already have the New York City Museums layer used in the previous recipes in this chapter, download the layer from https://geospatialpython.googlecode.com/svn/NYC_MUSEUMS_GEO.zip.
Unzip that file and place the shapefile's contents in a directory named nyc
within your qgis_data
directory, within your root or home directory.
In the following steps, we'll extract the first and last points in the layer's point order and measure their distance:
First, import the library that contains the QGIS contents:
from qgis.core import QGis
Then, load the layer:
lyr = QgsVectorLayer("/qgis_data/nyc/NYC_MUSEUMS_GEO.shp", "Museums", "ogr")
Access the features:
fts = lyr.getFeatures()
Get the first feature:
first = fts.next()
Set a placeholder...