Ah I get it ... So it detects node strings that form a "step" (a horizontal and a vertical combination). It may be good to make mappers aware that such a combination will trigger sawtooth detection by Eugene's script. For there are some coastline contours that are indeed on a step shape. Good way to avoid it is to move the nodes just a bit so the longitude/latitude pairings would not be exactly the same. I found this out on one of my Marinduque island edits.
thanks! On Tue, Jul 6, 2010 at 9:31 AM, maning sambale <emmanuel.samb...@gmail.com>wrote: > @ ed, > The technique is outlined here: > > http://wiki.openstreetmap.org/wiki/Talk:WikiProject_Philippines/Coastline_Corrections > > Couple of suggestions: > 1. short link to the coastline correction wikipage > 2. enable link to editors only at higher zoom level (perhaps 15-17?) > 3. should be an osm-ph image of the week > > On Tue, Jul 6, 2010 at 9:20 AM, Ed Garcia <eppgar...@gmail.com> wrote: > > Wow! amazing ... how do you detect "sawtoothness"? can you teach this at > > the skillshare? OSM genius ka talaga! > > > > Anyway, I take note of the sawtooth patterns between Lucena and Pagbilao > > Quezon ... I have corrected this already but the sawtooth appears only on > > higher zoom-out levels now. Does this mean it is good as "done" now? It > > still appears on yoursawtooth_coastlines map though. > > > > ed > > > > On Tue, Jul 6, 2010 at 1:04 AM, Eugene Alvin Villar <sea...@gmail.com> > > wrote: > >> > >> HI guys, > >> > >> Here's an *initial* webmap showing where the jagged coastlines are as of > >> July 3: > >> http://forge.codedgraphic.com/osm/sawtooth_coastlines/ > >> > >> The larger the circle, the more jagged steps there are to clean up. > >> > >> Sorry, there's no link going to Potlatch or JOSM/Merkaartor. I'll add > that > >> up when I learn more of OpenLayers. But for now, this will have to do. > >> > >> Enjoy! > >> > >> Eugene > >> > >> On Mon, Jul 5, 2010 at 9:30 AM, maning sambale > >> <emmanuel.samb...@gmail.com> wrote: > >>> > >>> We missed the June target to to finish the 10 largest islands. > >>> > >>> > http://wiki.openstreetmap.org/wiki/WikiProject_Philippines/Coastline_Corrections#Priorities > >>> > >>> That's OK. All we need is to finish mainland Mindanao and we can set > >>> our radar to the next 20 on the list. > >>> We are also working on some webmap to visualize the "sawtooth". More > >>> on that when its ready. > >>> > >>> > >>> On Sun, Jul 4, 2010 at 5:48 PM, maning sambale > >>> <emmanuel.samb...@gmail.com> wrote: > >>> > I can load it in my public dropbox. > >>> > > >>> > On Sun, Jul 4, 2010 at 2:23 PM, Eugene Alvin Villar < > sea...@gmail.com> > >>> > wrote: > >>> >> Hi guys, > >>> >> > >>> >> Once we are done with the large islands, the next step is to do the > >>> >> smaller > >>> >> islands. Ian Haylock has helpfully provided the PGS coastlines[1] > for > >>> >> the > >>> >> Philippines last year[2] which he edited to combine ways. PGS itself > >>> >> was > >>> >> automatically generated by a software by analyzing the Landsat > >>> >> imagery. > >>> >> Unfortunately, Ian's file was hosted on a free file server and has > now > >>> >> expired but I think several people on the mailing list managed to > >>> >> download > >>> >> it. > >>> >> > >>> >> I tried opening the file last year in Merkaartor but my old laptop > >>> >> couldn't > >>> >> handle the data. Now that I have a 4GB-RAM laptop, loading the data > >>> >> into > >>> >> Merkaartor is very manageable. Using the PGS coastlines is much, > much > >>> >> easier > >>> >> than tracing Landsat by hand. I tried this with Homonhon Island and > >>> >> editing > >>> >> is way faster than actually uploading it[3]. Hehehe. What I did was > to > >>> >> delete the SRTM-derived coastline[4] and replace it with the PGS > >>> >> coastline[5]. > >>> >> > >>> >> I think uploading the PGS coastlines is better for the smaller > >>> >> islands. I'll > >>> >> see what we can do to have the PGS coastlines (55MB) uploaded > >>> >> somewhere. > >>> >> > >>> >> [1] http://wiki.openstreetmap.org/wiki/Prototype_Global_Shoreline > >>> >> [2] > >>> >> > http://lists.openstreetmap.org/pipermail/talk-ph/2009-June/001071.html > >>> >> [3] http://www.openstreetmap.org/browse/changeset/5129873 > >>> >> [4] http://www.openstreetmap.org/browse/way/4327906 > >>> >> [5] http://www.openstreetmap.org/browse/way/65592780 > >>> >> > >>> >> Eugene > >>> >> > >>> >> > >>> >> On Thu, Jun 17, 2010 at 8:20 PM, maning sambale > >>> >> <emmanuel.samb...@gmail.com> > >>> >> wrote: > >>> >>> > >>> >>> UPDATE. Only two islands from the top ten need some coasty > coastline > >>> >>> love. > >>> >>> > >>> >>> > >>> >>> > http://wiki.openstreetmap.org/wiki/WikiProject_Philippines/Coastline_Corrections > >>> >>> > >>> >>> Anyone working on Negros and Mainland Mindanao? > >>> >>> > >>> >> > >>> >> > >>> > > >>> > > >>> > > >>> > -- > >>> > cheers, > >>> > maning > >>> > ------------------------------------------------------ > >>> > "Freedom is still the most radical idea of all" -N.Branden > >>> > wiki: http://esambale.wikispaces.com/ > >>> > blog: http://epsg4253.wordpress.com/ > >>> > ------------------------------------------------------ > >>> > > >>> > >>> > >>> > >>> -- > >>> cheers, > >>> maning > >>> ------------------------------------------------------ > >>> "Freedom is still the most radical idea of all" -N.Branden > >>> wiki: http://esambale.wikispaces.com/ > >>> blog: http://epsg4253.wordpress.com/ > >>> ------------------------------------------------------ > >>> > >>> _______________________________________________ > >>> talk-ph mailing list > >>> talk-ph@openstreetmap.org > >>> http://lists.openstreetmap.org/listinfo/talk-ph > >> > >> > >> > >> -- > >> http://vaes9.codedgraphic.com > >> > >> _______________________________________________ > >> talk-ph mailing list > >> talk-ph@openstreetmap.org > >> http://lists.openstreetmap.org/listinfo/talk-ph > >> > > > > > > > > -- > > website administrator: > > - www.waypoints.ph > > - reeflife.eppgarcia.com > > > > PADI Divemaster #491048 > > > > > > -- > cheers, > maning > ------------------------------------------------------ > "Freedom is still the most radical idea of all" -N.Branden > wiki: http://esambale.wikispaces.com/ > blog: http://epsg4253.wordpress.com/ > ------------------------------------------------------ > > _______________________________________________ > talk-ph mailing list > talk-ph@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk-ph > -- website administrator: - www.waypoints.ph - reeflife.eppgarcia.com PADI Divemaster #491048
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