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
> 
> 
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