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LoD1 City Model

param.json

To produce a City Model; necessary information that defines your area-of-interest (aoi) and coordinate reference system are parsed through a basic param.json. These are elaborated on below.

Table of contents

  1. Area-of-Interest
    1. village/campus
  2. crs
  3. raster DEM
    1. NoData
  4. CityJSON

Area-of-Interest

Due to the nature of the processing strategies aoi’s are defined differently

village/campus

    "LargeArea": "Western Cape",
    "FocusArea": "Mamre",
    "osm_type": "relation",

With the village/campus strategy an aoi is defined Large area -> focus area or State (Province) -> village / campus. The area must exist in osm as either a way or relation.

A number of param.json are available as Examples to illustrate its usage.

crs

"crs": "EPSG:32733",

defines the Coordinate Reference System (crs) of the City Model. The workflow will project the osm vector and raster DEM into a local coordinate system. EPSG code’s are supported.

raster DEM

    "in_raster": "./raster/LO19_050M_3318DC.tif",
    "nodata": 3.402823466385289e+38,
    "projClip_raster": "./raster/3318DC_clip_utm34s.tif",

One raster DEM will be enough for the village/campus strategy. Larger areas might require more.   The "in_raster" parameter will accept one or many (e.g.: "in_raster": "./raster/LO19_050M_3418BA.tif ./raster/LO19_050M_3318DC.tif",).

NoData values are recommend and the workflow will mosaic where necessary, clip and project an input raster DEM to the defined crs.

NoData

While village/campus and districts interactive.ipynb should execute successfully in any area; the CityJSON will not when an aoi extend’s into NoData (typically the ocean). This means these types of areas will fail to produce a LoD1 3D City Model while these will pass.

CityJSON

    "cjsn_out": "./result/citjsn_cput3d.json",
    ...
    "cjsn_CleanOut": "./result/citjsnClean_cput3d.json"

The "cjsn_out" City Model is parsed through a basic cleaning operation to remove duplicate and orphan vertices. "cjsn_CleanOut" thus has no superfluous features.