CityJSON (3D City Model)
Open BetaVie rakennukset CityJSON 2.0 -muotoon 3D-kaupunkimallinnusta varten. Tiivis JSON-muoto kärkipisteiden deduplikoinnilla. Tuettu 3DCityDB:ssä, QGIS 3D:ssä ja ninja-katseluohjelmassa.
Keskeiset ominaisuudet
Tietoa CityJSON-muodosta
CityJSON is a compact way of writing the same city model as CityGML, but in ordinary JSON instead of bulky XML. The same set of concepts (buildings, level of detail, attributes), only the file is many times smaller and is parsed by any language without special libraries. It is a recognized OGC community standard, not an amateur invention.
The format is chosen when a semantic 3D model is needed on the web, in scripts or in exchange between teams: to look at it in a browser viewer, to run it through Python, to put it into a repository, to hand it to colleagues without a heavy GIS stack.
The output is a single file: buildings at LOD1 detail are written as closed volumes extruded from OSM outlines. Vertices are stored as integers with millimeter precision through a scale factor and are deduplicated, so the file comes out noticeably lighter than the equivalent XML. The metadata records the coordinate system and the bounds of the model, and the buildings carry height, floor count and class.
Mikä ohjelma avaa CityJSON-tiedostot
Seuraavat ohjelmat ja sovellukset voivat avata ja muokata OSM2CDR:stä vietyjä CityJSON (3D City Model) (.city.json) -tiedostoja sekä työskennellä niiden parissa:
Format specifications
- Open standard
- 3D coordinates supported
- Lossless (no quality loss)
- Stores feature attributes
- Output: 1 file
- CityJSON 2.0 (OGC community standard). Lightweight JSON encoding of CityGML. Opens in QGIS plugin, ninja, FME.
Ketkä käyttävät CityJSON-karttoja
Näin viet kartan muotoon CityJSON
Kuinka avata viennin jälkeen
- ninja (a free web viewer for CityJSON) — drag the file into the browser window and see the model at once; the fastest way to check the result.
- cjio (Python, free) — the command cjio file.city.json info shows statistics and checks the structure, while export converts the model into OBJ or other formats.
- QGIS 3 — CityJSON opens through the 3D view, convenient for looking at the buildings together with the flat layers of the map.
- Blender — import through the CityJSON add-on, if the model is needed for visualization rather than for computations.
- 3DCityDB and FME — accept CityJSON on a par with CityGML, if the model is headed for a city database.
Suositut CityJSON-kartat
Hanki CityJSON (3D City Model) -karttavientejä
Lataa ammattilaistason CityJSON-karttoja OpenStreetMapista. Luodaan välittömästi mistä tahansa alueesta.
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