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> Keep in mind that many locations may have limited information about building geometry. In particular, the heights of buildings may be missing or incorrect in

by d33 10y ago

> Keep in mind that many locations may have limited information about building geometry. In particular, the heights of buildings may be missing or incorrect in many cities. How do they figure out the building heights at all then?

shocks 10y ago
Time of day and shadows? Just a guess.
- colejohnson66 10y ago
  It'd probably be easier to use aerial imagery
bjacobel 10y ago
High-resolution LiDAR and IFSAR. You can download some US elevation data for free from the USGS[1], other countries may have similar datasets available. [1]: https://viewer.nationalmap.gov/basic/?basemap=b1&category=ned,nedsrc&title=3DEP%20View https://viewer.nationalmap.gov/basic/?basemap=b1&category=ne...
- spyder 10y ago
  and probably photogrammetry from the arial photos.
  - colejohnson66 10y ago
    Which is what Google and Apple do. Pretty good, but it doesn't work well with trees
- gtvwill 10y ago
  Australia has a high res lidar available for free, about 300gb, I've been wanting to import it into blender but need a new hdd/more space to do it. I think the data was found here http://www.ga.gov.au/scientific-topics/national-location-information/digital-elevation-data http://www.ga.gov.au/scientific-topics/national-location-inf...
  - gtvwill 10y ago
    Sorry was about 300gb for nsw, not sure of other states/territories
  - Maxious 10y ago
    http://elevation.fsdf.org.au/ http://elevation.fsdf.org.au/ is starting to get data from LIDAR on a more local level, NSW/Sydney has some point cloud data up (presumably not just elevation but buildings/man made structures?) with more coming online every month until July 2018
rmc 10y ago
> How do they figure out the building heights at all then? I don't know how this software does it, but people are tagging "number of floors" for buildings, and you can get a decent estimate of building heights from that (by presume X metres per floor). When standing on the street, you can easily figure out the number of floors.
anigbrowl 10y ago
It's only a short step to pulling that information from Google Earth, which already has it for many cities.

by d33 10y ago

shocks 10y ago

Time of day and shadows? Just a guess.

colejohnson66 10y ago
It'd probably be easier to use aerial imagery

bjacobel 10y ago

High-resolution LiDAR and IFSAR. You can download some US elevation data for free from the USGS[1], other countries may have similar datasets available. [1]: https://viewer.nationalmap.gov/basic/?basemap=b1&category=ned,nedsrc&title=3DEP%20View https://viewer.nationalmap.gov/basic/?basemap=b1&category=ne...

spyder 10y ago
and probably photogrammetry from the arial photos.
- colejohnson66 10y ago
  Which is what Google and Apple do. Pretty good, but it doesn't work well with trees
gtvwill 10y ago
Australia has a high res lidar available for free, about 300gb, I've been wanting to import it into blender but need a new hdd/more space to do it. I think the data was found here http://www.ga.gov.au/scientific-topics/national-location-information/digital-elevation-data http://www.ga.gov.au/scientific-topics/national-location-inf...
- gtvwill 10y ago
  Sorry was about 300gb for nsw, not sure of other states/territories
- Maxious 10y ago
  http://elevation.fsdf.org.au/ http://elevation.fsdf.org.au/ is starting to get data from LIDAR on a more local level, NSW/Sydney has some point cloud data up (presumably not just elevation but buildings/man made structures?) with more coming online every month until July 2018

rmc 10y ago

> How do they figure out the building heights at all then? I don't know how this software does it, but people are tagging "number of floors" for buildings, and you can get a decent estimate of building heights from that (by presume X metres per floor). When standing on the street, you can easily figure out the number of floors.

anigbrowl 10y ago

It's only a short step to pulling that information from Google Earth, which already has it for many cities.