http://postgis.refractions.net/documentation/manual-1.5/ST_Collect.html http://postgis.refractions.net/documentation/manual-1.5/ST_Union.html
On Sep 20, 2010, at 8:51 PM, Simpson Brad-C-Lockheed wrote: > Dane, > > I should have read all of your Friday’s email. I’m not trying to hide lines > between tiles. Actually, I’m interested in collecting the geometries so that > no tiles exists, in effect generating coastlines. Is there a PostGIS > operation which can do this? Alternatively, the source of the data used to > generate shoreline_300 may be a better place to start. Is the source data > for shoreline_300 available on the web? > > Brad > > From: Dane Springmeyer [mailto:[email protected]] > Sent: Monday, September 20, 2010 12:01 PM > To: Simpson Brad-C-Lockheed > Cc: mapnik-users > Subject: Re: [Mapnik-users] Projection problems > > Brad, > > Try setting gamma=".6" in your PolygonSymbolizer as per: > > http://trac.mapnik.org/wiki/PolygonSymbolizer#DefaultfillwithGammacorrection > > Dane > > On Sep 20, 2010, at 7:23 PM, Simpson Brad-C-Lockheed wrote: > > > Dane, > > The no_overlap* files are what the name implies – no overlapping of the > tiles. However, I still can’t plot shorelines without getting a crosshatch > pattern because of the non-overlapping tiles. Is there an un-tiled version? > > Brad > > From: Dane Springmeyer [mailto:[email protected]] > Sent: Thursday, September 16, 2010 6:18 PM > To: Simpson Brad-C-Lockheed > Cc: Jon Burgess; [email protected]; Christopher Schmidt; Robert Coup; mapnik-users > Subject: Re: [Mapnik-users] Projection problems > > > On Sep 17, 2010, at 1:45 AM, Simpson Brad-C-Lockheed wrote: > > > > I'm hoping to solicit some advice regarding shoreline_300. We'd like to use > it since it is an improvement over the data currently employed. We'd like to > plot it with a matching coastline where we can adjust its style (color, > width, etc.). > > If I use the LineSymbolizer (along with the PolygonSymbolizer to fill in land > areas) on shoreline_300, I get in addition to a coastline, an undesired > cross-hatch pattern. This is because the land polygons have been tiled. > > Yes. Well, because they have been tiled, with an overlap. > > There are a set of versions that do not have overlap that Jon produced as a > test recently that might be helpful: > > http://tile.openstreetmap.org/no_overlap_processed_p.tar.bz2 > http://tile.openstreetmap.org/no_overlap_shoreline_300.tar.bz2 > > (note that shoreline_300 is a simplified version of processed_p) > > > > > Is there an un-tiled version of shoreline_300 available? > > To get an untiled version I would import the shapefile into postgis and > collect the geometries (but beware this will be a very expensive operation). > > Hopefully you can make due with tiled files without overlap. To get rid of > the slight lines that will appear in the non-overlapping version try setting > gamma=".7" in your PolygonSymbolizer. > > > > Is there a matching coastline_300 file? If not, what do you recommend for > getting around this problem? > > Any advice would be appreciated. Thanks, > > Brad > > -----Original Message----- > From: Jon Burgess [mailto:[email protected]] > Sent: Wednesday, September 15, 2010 11:51 AM > To: Simpson Brad-C-Lockheed > Cc: Christopher Schmidt; Dane Springmeyer; mapnik-users; Robert Coup; > [email protected] > Subject: RE: [Mapnik-users] Projection problems > > On Wed, 2010-09-15 at 09:34 -0600, Simpson Brad-C-Lockheed wrote: > > > Chris, > > Thanks for responding. I understand the spatialreference map is coarse and > low resolution. However, my position is all coordinates in the general area > are shifted (although I have only looked in the English Channel area and the > Greek Islands so far). And the vmap0 data matches our database. I've only > given one example that is easy to confirm. I do not believe this is a case > of the data being too coarse. > > I would like to migrate from our old database (heritage unknown) to > openstreetmap, but I can't unless I can account for this discrepancy. > > This map comparison between OSM and Google satellite shows a good match: > > http://tools.geofabrik.de/mc/?mt0=mapnik&mt1=googlesat&lon=-2.22122&lat=49.701&zoom=16 > > > This comparison with Yahoo satellite data also shows a good match: > > http://sautter.com/map/?zoom=13&lat=49.70034&lon=-2.22001&layers=00000BTFFFFFFF > > It looks like the footpath shown in OSM has been uploaded as a GPX trace > which seems to add further confirmation that the island is probably > shown in the correct position in OSM. I guess you can look for more 3rd > party data to confirm the location, or failing that, you'll need to go > there yourself :) > > Jon > > > _______________________________________________ > Mapnik-users mailing list > [email protected] > https://lists.berlios.de/mailman/listinfo/mapnik-users > >
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