[OSM-dev] OSM Level of Detail for GSoC 2017

2016-12-20 Thread Balázs Dukai
Hi Peda,

yes indeed, yours is a very pertinent question. For the problem of 
differentiating between low-detail complex buildings and high-detail 
simple buildings currently I have two ideas. One, check the spatial 
distribution of the level of detail. This is based on the assumption 
that buildings in a spatial cluster are mapped in similar level of 
detail. I'm aware that there are several exceptions to this that might 
make my assumption invalid. Secondly, use an authorative data set to 
compare the detail of the footprints. Again, assuming that the 
authorative data set is consistent in its level of detail.

I admit that I was not aware of your second point, so thank you for 
bringing it to my attention. Which also helps me understand the 
limitations of such a method to enrich the OSM database. I will still 
work with OSM data in my thesis, however my project for GSoC 2017 if off 
the table.

In general, my work is focused on the statistical comparison of 
footprints or 3D buildings by using a machine learning approach. However 
I'm still in the middle of developing the method, and ultimately I would 
like to know that until what extent is the automatic inference of LOD 
possible.

Thank you very much for your feedback!
Balázs

-- 
Balázs Dukai
MSc Geomatics engineer candidate | MEng Landscape architect
The Hague, Netherlands
LinkedIn: www.linkedin.com/in/balazsdukai
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[OSM-dev] OSM Level of Detail for GSoC 2017

2016-12-16 Thread Balázs Dukai
Hello everyone,

as I'm a newcomer to this list please let me introduce myself. My name 
is Balázs Dukai, I'm currently studying geomatics engineering at TU 
Delft, Netherlands and I was not active in the OSM development community 
until now. I'm moderately experienced with OSM, last year I organized 
two Missing Maps parties at TU Delft and I use OSM mainly for 
downloading vector data to prepare base maps. This summer (2016) I 
participated in the GSoC, however under the umbrella of the R project 
and I developed a package to manage animal trajectories in PostGIS and 
R[1,2]. Since then I started working on my thesis which brings me to 
this mailing list.

In my research I'm developing a method to automatically infer the Level 
of Detail (as in CityGML) of heterogeneous 3D city models. Experience 
shows that several 3D city models contain buildings that are tagged as 
e.g. LOD2, however they are modeled as LOD1. This heterogeneous data 
negatively influences the accuracy of analysis that depends on the 3D 
geometry, such as energy profiling, solar irradiation, wind flow 
analysis. Also it is good to know that the data set one purchased is 
truly in-line with its description, e.g. all buildings are really LOD2. 
Visually assessing the LOD of each building is not feasible at a city 
scale, hence the automatic inference.

Now, in order to have an idea about the LOD of the 3D building, a good 
way to start is to evaluate its footprint. As the geometric detail of 
the footprint indicates the geometric detail of the building. My 
assumption is that having an indication (a tag maybe) of the detailed 
LOD[3] of the 2D building footprints in OpenStreetMap could provide some 
benefits, such as

+ identify areas where the buildings are mapped in a low LOD and 
could/should be improved,

+ users could easily see the LOD of buildings (LOD tag) when 
programmatically querying/downloading OSM data and better evaluate its 
fitness-for-purpose.

Therefore I propose that in the scope of GSoC 2017 I work towards a 
tool/method that automatically appends the detailed LOD[3] tag to 
building footprints in OSM. Maybe even the potential LOD of the 3D 
building that can be generated with tools such as OSM2World...

My thesis is still in an initial phase but I'll have my method clear by 
February and I plan to submit in May-June.
The reason why I wrote this general mailing list and not to the 
osm-tagging list is that I'm very curious about any idea, critic on my 
thesis or GSoC project idea. So I hope this will open a discussion.

I was thinking to target the osm-tagging list but I'm not sure if that 
is the most appropriate. Could you advise me is this matter as well?

[1]: https://github.com/mablab/rpostgisLT/wiki/GSoC-2016
[2]: https://cran.r-project.org/package=rpostgisLT
[3]: http://www.sciencedirect.com/science/article/pii/S0198971516300436

Best regards,
-- 
Balázs Dukai
MSc Geomatics engineer candidate | MEng Landscape architect
The Hague, Netherlands
LinkedIn: www.linkedin.com/in/balazsdukai
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