Following the streets parser/creator improvements of the Blended Cities script, I resumed work this week on the use of real plans. OpenStreetMap is a data source must! and of course an excellent file standard to retain the characteristics of a city, that could be used for Blended Cities..
as a definition, and compared to GoogleMap :)
"OpenStreetMap creates and provides free geographic data such as street maps to anyone who wants them.."
"OpenStreetMap is open data, licensed under the Creative Commons Attribution-ShareAlike 2.0 licence (CC-BY-SA).
You are free to copy, distribute, transmit and adapt our maps and data, as long as you credit OpenStreetMap and its contributors. If you alter or build upon our maps or data, you may distribute the result only under the same licence. The full legal code explains your rights and responsibilities."..
in particular, it can export a map in XML format...
that Blended Cities will be able to use as a data source.
here the importation contains only the streets:
the .osm files (XML format) contain not only roads (and lanes), but many other types of information such as subway stations, buildings or parks perimeters, street names..
below is another import with all geometrical data, with blocks in addition to street :
the 3rd step, namely the creation of the network node and volumes representing the streets and block, is still buggy, but by cleaning up a bit the source mesh :
It will need an international lookup table for the types of lanes or perimeters described in the xml file, in order to translate them into Blended Cities volumes and objects. perimeters could also be used to define the buildings lots... a large and exciting work in perspective ( Help ! )
technically, the geographic coordinates (latitude and longitude) are converted to meters at importation, using the UTM projection and the WGS84 datum, thanks to the functions written and/or ported to python by Russell Nelson ( http://pygps.org/ ). many thanks to him!