Processing Options, Strategies and Requirements

1. Processing Options

There are two processing options

Village	Suburb
village is designed for extremely focused analysis at a neighbourhood level. These are areas with no more than 2 500 buildings	For larger areas with more than 2 500 buildings; such as suburbs, census wards or tracts; please execute suburb. The suburb processing option caters for regions with no internet access.
village harvests OSM contributions via overpass-turbo in GeoJSON format	an osm.pbf is necessary With more substantial volumes of data; suburbs extracts the necessary building outlines from the osm.pbf format (Protocolbuffer Binary Format)

within each processing option; there are two strategies

2. Processing Strategies

osm_LoD1_3DCityModel	interactiveOnly
Product: An Open Geospatial Consortium (OGC) standard LoD1 3D model adhering to the International Standards Organisation (ISO19107) scheme for 3D primitives. These simulation-ready models provide quantitative insights with such use cases as estimating noise propagation, energy demand and wind comfort factor.	Product: A colorised pseudo-3D HTML-based visualisation. The visualisation is for user interaction, navigation, and sharing, promoting community engagement and understanding
a raster DEM is necessary

3. Data Sources

osm.pbf

OSM Proto-buff files can be harvested from a number of sources. Either crop an area directly from OpenStreetMap with the official tool, select a predefined area from any number of providers, such as Geofabrik, or… download your own.
e.g.: Provincial extracts for South Africa are available here: http://download.openstreetmap.fr/extracts/africa/south_africa/

raster DEM

For the purposes of geo3D a raster Digital Elevation Model (DEM) is the surface of the earth free of man-made and natural features. These are available from a number of on-line sources; most notably OpenTopography. Almost all government agencies responsible for spatial data; open source their elevation data.

In South Africa this service this via the Chief Directorate: National Geo-spatial Intelligence CD:NGI Geospatial portal.

be aware: geo3D; is a grass-roots learning tool for fine scale analysis at a local level. The very structure and methodology of geo3D reinforces this key theme; neighbourhood-level, place- and inquiry-based learning where users have directly contact with, and knowledge of the, environment under investigation. Fine-scale elevation models (with a resolution less than 10-meter) come at a computational cost.