Multiple operations within Field Calculator using the same IF statement

Question

I have 2 layers (Point_Orien_Vert - red points and Point_Centroides - green points), both are Point Geometry.

I need first to check if the distance between one feature in Point_Orien_Vert and one feature in Point_Centroide is smaller than 180 m.

The code below shows how to calculate this distance and it works inside a IF statement.

distance(
 @geometry, 
 closest_point(
  geometry(
   get_feature_by_id(
    'POINT_Centroides',
     array_to_string(
      overlay_nearest(
       'POINT_Centroides', "fid"
      )
     )
    )
   )
  , @geometry
 )
)

If the result is true, I need to calculate in Point_Orien_Vert layer the difference between the value stored in "Dip_Direct" and the value "Azimute".

Note that a feature from Point_Centroide will be checked more than an once time from points in Point_Orien_vert because the distance.

I do not know how to write this second code using self-referencing geometry to do this operation.

Answer 1

• The closest point of a point geometry, is the point itself. Also, the distance between geometries, is the distance between their closest points.

• "fid" attribute may or may not have the id of the feature as its value. If you delete the feature where "fid" = 1, the second feature "fid" value remains as 2, but its new id is 1.

• Anyways, you don't need its id nor its "fid" value, you need the feature itself. Use the @feature expression in the overlay_nearest function.

• Don't convert the array to string, get its first item. Even if you were getting the id, this is a number not a string.

• Store the feature in a variable for later use in the if clause.

with_variable( 'closestfeature',
 overlay_nearest( 
  layer:='POINT_Centroides',
  expression:=@feature)[0], --slice index 0 to get the first array item
if(
 distance(@geometry, geometry(@closestfeature)) < 180, --condition
 "Dip_Direct" - attribute(@closestfeature, 'Azimute'), --expression for True
 NULL) --expression for False
)