Thank you Dane, this is an excellent information, I just know about cairo. John
On Tue, Mar 3, 2009 at 8:29 AM, Dane Springmeyer <[email protected]> wrote: > Hi John, > > Envelope and Coord objects are only used to zoom or orient the map. They > don't get rendered as shapes themselves on the map. > > If you want to draw shapes on a map that do not originate from a > datasource, then take a look into Cairo. Mapnik trunk supports both cairo > contexts and cairo surfaces, so you can use pycairo ( > http://cairographics.org/pycairo/) to draw arbitrary shapes on a context > before/after rendering. > > Also there is support for plotting points manually on the map surface via > the PointDatasource, but this has not yet been extended to lines or > polygons, and is undocumented. However you can find a script example here: > http://mapnik-utils.googlecode.com/svn/example_code/memory_datasource/ > > Cheers, > Dane > > > > On Mar 3, 2009, at 12:58 AM, John3478 John3478 wrote: > > Hi, >> >> I am kind of stuck how to draw rectangle line based on bbox value (lower >> bottom and upper corner). >> There are LineSymbolizer but seems like it does not base on drawing line >> between to point. >> There are some example from this forum that use LineSymbolizer in Python >> but the line represent the shape >> not drawing line between two point. >> >> Thank you in advance, >> John >> >> >> ------------------------------------------------------------------------------------------------ >> projection = '+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 >> +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgri...@... +no_defs +over' >> m = Map(600,300,projection) >> m.background = Color('steelblue') >> m.srs = projection >> s = Style() >> r = Rule() >> r.symbols.append(PolygonSymbolizer(Color('#f2eff9'))) >> r.symbols.append(LineSymbolizer(Color('rgb(50%,50%,50%)'),2)) >> s.rules.append(r) >> m.append_style('My Style',s) >> lyr = Layer('world') >> lyr.datasource = Shapefile(file=world_borders') >> lyr.styles.append('My Style') >> lyr.srs = '+proj=latlong +datum=WGS84' >> m.layers.append(lyr) >> p = Projection(projection) >> lower_left_xy = p.forward(Coord(-180.0, -45.0)) >> upper_right_xy = p.forward(Coord(180.0, 80.0)) >> bbox = Envelope(lower_left_xy,upper_right_xy) >> m.zoom_to_box(bbox) >> render_to_file(m,'test41.png', 'png') >> _______________________________________________ >> Mapnik-users mailing list >> [email protected] >> https://lists.berlios.de/mailman/listinfo/mapnik-users >> > >
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