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Table 1 Datasets converted (see Fig. 3)

From: CityJSON: a compact and easy-to-use encoding of the CityGML data model

  CityGML CityJSON  
  Size(a) No space(b) LoD Texture Size-float(c) Size-int(d) Compr.(e)
Den Haag(1) 23 MB 18 MB 2 Material 3.1 MB 2.9 MB 6.2
Montréal(2) 56 MB 42 MB 2 Yes 5.7 MB 5.4 MB 7.8
New York(3) 590 MB 574 MB 2 No 110 MB 105 MB 5.5
Railway(4) 45 MB 34 MB 3 Yes 4.5 MB 4.3 MB 8.1
Vienna(5) 37 MB 36 MB 2 No 5.6 MB 5.3 MB 6.8
Zürich(6) 435 MB 423 MB 1 No 127 MB 100 MB 4.4
  1. (a)size does not take into account the size of the textures files (PNG, JPG, etc) since CityJSON refers to the same ones
  2. (b)the carriage returns, tabs, and spaces are removed, for a fair estimation of the compression factor
  3. (c)coordinates represented as double/float
  4. (d)coordinates represented as integer (compressed files)
  5. (e)compression factor = CityGML(no spaces) / CityJSON(size-int)
  6. (1)tile 01, https://data.overheid.nl/data/dataset/ngr-3d-model-den-haag
  7. (2)tile VM05, https://tinyurl.com/y8eglpmn
  8. (3)LoD2 tile DA13, https://www1.nyc.gov/site/doitt/initiatives/3d-building.page
  9. (4)CityGML v2 demo Railway, https://www.citygml.org/samplefiles/
  10. (5)the demo file, https://tinyurl.com/yaopvy6w
  11. (6)version with Max height, https://data.stadt-zuerich.ch/dataset/geo_3d_blockmodell_lod1