OpenStreetMap buildings

Autogen Scenery

Started in	11/2013
Description	Improved autogen support for FlightGear using OSM data
Contributor(s)	radi, vanosten, Soitanen, portreekid
Status	Under active development as of 02/2016
Topic branches:
$FG_SRC	https://gitlab.com/osm2city/osm2city/
fgdata	https://gitlab.com/osm2city/osm2city-data/

OSM generated buildings and roads.

Houses with gable roofs.

Buildings can be mapped in OpenStreetMap. Their shapes can be turned into 3D models for use in FlightGear scenery.

Challenges

• There are "just" 64 million buildings in OSM, most cities in the world have no buildings at all or just a few.
• Only 1.04% of the buildings in OSM have a height specified. Ca. 1.4% has a known number of floors (levels).
• FlightGear cannot handle thousands of models in a view. Grouping models into bigger files improves performance to a very usable level, but is less practical unless automated.

Tools

A perl script (bob.pl) is being written to turn the OSM data into 3D models. It is available at https://gitorious.org/fgscenery/tools?p=fgscenery:tools.git;a=summary.

osm2city.py is another project, under active development as of 06/2014.

Note for Windows

• Windows does not contain perl by default. You're advised to install Strawberry Perl for Windows. It is a simple installer; no need to dig into your system.
• Cygwin is also advised, so "grep" can be used to get a list of building ids easily.
• When working with shapefiles not coming from OSM you will need ogr2ogr, which is included in FWTools.

From OpenStreetMap

A single building

1. Find the building in OpenStreetMap.
2. Enable the "Data" overlay.
3. Choose a manual area and drag a box around your building.
4. Click your building, the way id will be shown. Copy this id.
5. Run the following code, replacing 44338398 with your building's id:

perl bob.pl -w 44338398

Next to this basic code, there are several options, to be added behind the basic code.

• Lat/lon location of the model's origin:

-lat 52.00141 -lon 4.36966

• Object name (not the .ac name!):

-n "Empire State Building"

• Building height (in meters):

-h 15

Note: buildings are always sunk 5 m into the ground, in order to account for non-flat terrain. These 5 meters are added on top of (or below, if you like) the building height.

• Create a xml file with a standard range animation:

-x

• Clean the shape by removing nodes that lie within a certain distance from the line that connects its two adjacent nodes. This results in much smaller files and allows more buildings to have a gable roof:

-clean

All buildings in an area

Lower Manhattan at dawn.

1. Download a file with all data from the area, by visiting the following link and save it somewhere on your computer. This will only include buildings (building=yes) within the specified bounding box.

   http://overpass-api.de/api/xapi?way[bbox=left,bottom,right,top][building=*][@meta]

   For example:

   http://overpass-api.de/api/xapi?way[bbox=-74.02037,40.69704,-73.96922,40.73971][building=*][@meta]

2. Get a list of wayids via grep "<way" map.osm|cut -f2 -d\">wayids.txt change the number after f where appropriate
   or sed -n 's|<way.*id="\(.*\)" .*>|\1|p' "map.osm" > wayids.txt
3. For Windows users: Run for /f %a in (wayids.txt) do perl bob.pl -w %a -f map.osm
   For others: Iterate through wayids.txt and assign each way id to $object and run perl bob.pl -w $object -f map.osm on all the ids.

#!/usr/bin/perl

while ($wayid =<STDIN>) {
    system("./bob.pl -v -w $wayid ");
}

From another source

1. Run ogr2ogr with:

   ogr2ogr -t_srs WGS84 -s_srs "ESRI::in_shp.prj" "out_shp.shp" "in_shp.shp"

2. Run shp2osm with:

   perl shp2osm.pl "out_shp.shp" > "map.osm"

3. Get a list of wayids via grep "<way" map.osm|cut -f2 -d\">file.txt
4. Run perl bob.pl -w $object -f map.osm on all the ids.

Related content

• Osm2city.py

External links

• Building attributes (OSM wiki)
• Roof type Library (OSM wiki)

References