Extracting x,y coordinates from QgsGeometry: Point(x, y) using PyQGIS

Question

I'm trying to extract the coordinates of a feature vertex. When I write on my editor

print(vertex)

what I get is

<QgsGeometry: Point(58746.43000004297, -256665.088999123)>

But when I try to extract the coordinates,

print(vertex.x)

I get:

AttributeError: 'QgsGeometry' object has no attribute 'x'

How do I extract the coordinates x, and y?

If it is not possible with <QgsGeometry: Point(x,y)>, then how do I simply convert to a form that allows me to extract the coordinates?

Answer 1

I could get the same exception AttributeError:

Traceback (most recent call last):
  File "C:\OSGeo4W\apps\Python39\lib\code.py", line 90, in runcode
    exec(code, self.locals)
  File "<input>", line 1, in <module>
  File "<string>", line 4, in <module>
AttributeError: 'QgsGeometry' object has no attribute 'x'

after running the following code:

from qgis.core import QgsGeometry
vertex = QgsGeometry.fromPointXY(QgsPointXY(58746.43000004297, -256665.088999123))
print(vertex.x)

When one types print(type(vertex)) it returns you a QgsGeometry class.

There are several approaches you may get the x and y coordinates of a vertex/point:

1. One way is to convert the QgsGeometry class into a QgsPointXY class using the asPoint() method and then using two others methods x() and y() to get your coordinates.

   from qgis.core import QgsGeometry, QgsPointXY
   geom = QgsGeometry.fromPointXY(QgsPointXY(58746.43000004297, -256665.088999123))
   pt = geom.asPoint() # QgsPointXY
   print(pt.x(), pt.y())
   

2. From another side the QgsGeometry class possess a vertexAt() method that will return a QgsPoint representing a vertex at a certain index. I have not seen your features, but most likely each QgsGeometry is not a multi-part, which means each contains only one point. Hence, one may simply approach each geometry via a 0-index and afterwards use the x() and y() methods again.

   from qgis.core import QgsGeometry, QgsPointXY
   geom = QgsGeometry.fromPointXY(QgsPointXY(58746.43000004297, -256665.088999123))
   pt = geom.vertexAt(0) # QgsPoint
   print(pt.x(), pt.y())
   

3. There is a constGet() method of the QgsGeometry class available.

   Returns a non-modifiable (const) reference to the underlying abstract geometry primitive.

   from qgis.core import QgsGeometry, QgsPointXY
   geom = QgsGeometry.fromPointXY(QgsPointXY(58746.43000004297, -256665.088999123))
   geom_ = geom.constGet()
   print(geom_.x(), geom_.y())
   

All the above solutions will return the same output:

58746.43000004297 -256665.088999123

---

References:

• Difference between QgsPoint, QgsPointXY and QgsGeometry.fromPointXY() in PyQGIS