Creating Textures from OSM-Data, Issue with forest

mlankenau · 2019-05-28T07:20:38.000Z

Hi,

I try to create a terrain renderer for unity3d using elevation data. Since I am to lazy to paint all the forest-areas and streets, I try to use OSM data to paint images, that describe the kind of landuse for each location. Right now I am only trying to render forest.

My current output is

The Problem is the white area on the top right (arrow). It looks like I am missing one large polygon. I am going through all the relations and draw all referenced ways that have outer in green in all that have inner in grey (to see them). In addition I go through all ways that have landuse=forest and draw them as polygon as well.

I think that I misunderstood the relation thing.

The code can be found here:
https://gist.github.com/mlankenau/cf6a7528020c77deb26899eb49544f95

Any help is highly appreciated

SomeoneElse · 2019-05-28T08:57:48.000Z

Can you link to that area in OSM?

mlankenau · 2019-05-28T09:27:17.000Z

sure: is this link helpful:
https://www.openstreetmap.org/#map=13/47.7356/12.4648

the image is a little bit stretched in y dimension.

Tordanik · 2019-05-28T21:24:05.000Z

Just a guess, as I couldn’t find the particular forest multipolygon that’s causing you trouble and have only scanned your code, but: Are you handling non-closed ways correctly? Any outer or inner ring of a multipolygon may potentially consist of more than one way, like in this illustration:

SomeoneElse · 2019-05-28T21:27:32.000Z

mlankenau:

sure: is this link helpful:
https://www.openstreetmap.org/#map=13/47.7356/12.4648

Not really - there’s no idea of scale in the posted image, and the map link at zoom 13 covers a huge area.

mlankenau · 2019-05-29T05:11:10.000Z

Tordanik:

Just a guess, as I couldn’t find the particular forest multipolygon that’s causing you trouble and have only scanned your code, but: Are you handling non-closed ways correctly? Any outer or inner ring of a multipolygon may potentially consist of more than one way, like in this illustration:

https://wiki.openstreetmap.org/w/images/1/10/Multipolygon_Illustration_3.svg

I think that is exeactly my problem. I did not understand that the outer boundary could consist of more than one way.

Thx alot for your help!