Demo: Build City Mesh from CityJSON¶

This demo illustrates how to build a mesh for a CityJSON city model.

To run the demo, type:

$ python build_city_mesh_from_cityjson.py

Purpose¶

This demo demonstrates how to download a CityJSON file from an external URL, load the city model from the file using DTCC, build a city mesh at a specified level of detail (LOD2 in this case), and visualize the resulting mesh.

Step-by-step¶

1. Download CityJSON File: Retrieve the CityJSON file from a specified URL. This file contains the city model data in the CityJSON format.

   from urllib.request import urlretrieve
   url = "https://3d.bk.tudelft.nl/opendata/cityjson/3dcities/v2.0/DenHaag_01.city.json"
   urlretrieve(url=url, filename="city.json")
   

2. Load City Model: Load the city model from the downloaded CityJSON file using the load_city function provided by DTCC.

   import dtcc
   city = dtcc.load_city("city.json")
   

3. Build City Mesh: Generate a city mesh from the loaded city model. Here, the mesh is built at level of detail LOD2.

   mesh = dtcc.build_city_mesh(city, dtcc.GeometryType.LOD2)
   

4. Visualize the Mesh: View the generated city mesh using the view() method.

   mesh.view()
   

Complete Code¶

Below is the complete code for this demo:

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# This demo illustrates how to build a mesh for a CityJSON city model.

import dtcc
from urllib.request import urlretrieve

# Download example CityJSON file
url = "https://3d.bk.tudelft.nl/opendata/cityjson/3dcities/v2.0/DenHaag_01.city.json"
urlretrieve(url=url, filename="city.json")

# Load city model from CityJSON file
city = dtcc.load_city("city.json")

# Build city mesh
mesh = dtcc.build_city_mesh(city, dtcc.GeometryType.LOD2)

# View mesh
mesh.view()