Jean-Marc Liotier wrote: > I have noticed that in many places, in countries in which > Google does not have significant commercial interest, even many villages > have part of their street grid mapped. But looking a little closer, this > is a partial mapping of a seemingly random subset of the grid, and none > of those streets have names. [..] > > So is anyone aware of automated tracing techniques that Google might be > using ? Is automated tracing from legally available imagery something > that the Openstreetmap project should study ? Street grid detection and > automated tracing would make a nice JOSM plugin wouldn't it ? > > Lakewalker does it for waterlines > (http://wiki.openstreetmap.org/wiki/JOSM/Plugins/Lakewalker) and > coastline tracing of Landsat imagery using other tools has been > experimented with > (http://www.mail-archive.com/talk@openstreetmap.org/msg12661.html). > Other people have been playing with Potrace and Autotrace > (http://wikitravel.org/en/Wikitravel_talk:How_to_draw_a_map#Automated_tracing_potrace_vs._autotrace) > > But I have found no mention of street tracing automation yet.
Some other sources mentioning automatic feature extraction methods : - Automatic extraction of road and water surface from SPOT-5 Pan-Sharpened Image : http://mapasia.org/2009/proceeding/ip/ma09_Panu.pdf - Potential of manual and automatic feature extraction from high resolution space images in mountainous urban areas : http://www.isprs.org/proceedings/XXXVIII-1-4-7_W5/paper/TOPAN-174.pdf - Road identification from satellite images based on a fuzzy reasoning model : http://www.gisdevelopment.net/proceedings/mapmiddleeast/2008/mme08_22.pdf - Automatic road extraction from remotely sensed imagery : http://www.icrest.missouri.edu/Projects/NASA/FeatureExtraction-Roads/index.htm Look at the examples and you'll see patterns very similar to the imprecise anonymous streets produced by Google. They convinced me that Google is definitely extracting them automatically from orbital imagery. I'm amazed that I can't find any other reference to that on the Web. The mediocre quality of Google's results for now hint at a maturing field, but that sort of automation is a huge leverage on available imagery. Manual improvement of the resulting ways will still be needed, but whoever puts those techniques to good use will gain global coverage at very low cost while conserving precious human resources to focus them on tasks adding even more value to the map. _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
