I find the Yahoo satellite imagery useful for tracing in JOSM with wmsplugin, but when I just want to gaze at stunning sights of Earth's surface I go to Google, the quality of whose imagery never ceases to amaze me. 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. Example in Takoradi, Ghana : http://j.mp/7Ay7wZ. This looks like what some grid recognition automaton would produce if configured to only trace the streets it detects with a certainty above a certain threshold. The result is imperfect, but it looks like a nice way to kickstart manual mapping of an area with the techniques we currently use.
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. _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
