Creating square polygons of given length from single corner point in QGIS

Question

I have 30 points, each one represents the SE corner of a 1.5 by 1.5m plot. I want to create polygons to represent these plots.

How do I create square polygons from a corner point and with a specific length?

Answer 1

There is "Vector geometry > Geometry by Expression" tool in Processing Toolbox. You should use in a projected coordinate system.

• Select "Polygon" as "Output geometry type" option.

• Click "Expression" button (highlighted blue square)

• And paste the following expression

  make_rectangle_3points(  
    make_point($x, $y), 
    make_point($x, $y + 1.5),
    make_point($x - 1.5, $y + 1.5)
  )
  

Result:

Answer 2

Use geometry by expression to create a point at 315 degrees azimuth from your point with a distance of the hypotenuse of the square, then create a box around the two points:

bounds(collect_geometries( $geometry, project( $geometry, sqrt(2*1.5^2),  radians(315))))