Isometric OMF Buildings

Date: September 19, 2024
Technology: QGIS, Overture
Fun Fact: The pinnacle of my childhood doodling was drawing isometric cubes.

Style buildings from Overture Mapping Foundation using geometry generators in QGIS.

  1. Start by downloading @newgeographer2's geopackage (found here), which includes the full style customized to work with OpenStreetMap buildings.

  2. Download OMF buildings using the method of your choice (instructions).

  3. OMF data will be in a geographic (lat/lng) coordinate reference system. Reproject the downloaded data to a projected coordinate reference system.

  4. Add downloaded geopackage and buildings to QGIS.

  5. Copy style from geopackage, paste style into buildings.

  6. Open buildings Properties -> Symbology tab. Open the rule-based symbol properties.

    a. Clear the filter.

    b. Change the first Geometry Generator layer expression to:

    translate( 
    $geometry,
    cos( radians( @qgis_25d_angle ) ) * max("height" * 2, 20), 
    sin( radians( @qgis_25d_angle ) ) * max("height" * 2, 20)
)

    c. Change the second Geometry Generator layer expression to:

    order_parts(
    extrude(    
        segments_to_lines( $geometry ),    
        cos( radians( @qgis_25d_angle ) ) * max("height" * 2, 20),
        sin( radians( @qgis_25d_angle ) ) * max("height" * 2, 20)
    ), 
    'distance( 
        $geometry,  
        translate(   
            @map_extent_center,    
            1000 * @map_extent_width * cos( radians( @qgis_25d_angle + 180 ) ),    
            1000 * @map_extent_width * sin( radians( @qgis_25d_angle + 180 ) )  
        )
    )', 
    False
)

Demo

QGIS: