Finding the shortest distance between two selected polygons using PyQGIS

Question

I'm researching the shortest distance between two selected polygons among the number of polygons in a shapefile using PyQGIS. Coding as follows>

layer = iface.activeLayer()

sFeat1 = layer.getFeature(0)
tFeat1 = layer.getFeature(1)

sGeom1 = sFeat1.geometry()
tGeom1 = tFeat1.geometry()

dist_m1 = sGeom1.distance(tGeom1)
print(dist_m1)

The problem is that it always returns the same distance, despite the selected polygon. What is wrong with my code?

Answer 1

In your script, you always get the features whose ids are 0 and 1, which are always the same features, not the selected features. Instead, you need to get selected features. Use this script:

layer = iface.activeLayer()

# get selected features list
features = layer.selectedFeatures()

sFeat1 = features[0]
tFeat1 = features[1]

sGeom1 = sFeat1.geometry()
tGeom1 = tFeat1.geometry()
dist_m1 = sGeom1.distance(tGeom1)
print(dist_m1)

Two features must be selected in the active layer for the code to work.