Great, thanks for following through on your solution mark. Dane
--- \o/ --- Sent from my phone On Jul 9, 2011, at 4:55 PM, Mark Vahrenwald <[email protected]> wrote: > Thank you Dane. I ended up just creating all the layer definitions by hand, > one for each state directory, and set them to reference a single layer style. > Not elegant, but it works fine. > Thanks for the tip. > Mark > > On Jul 7, 2011, at 2:44 PM, Dane Springmeyer wrote: > >> On Jul 7, 2011, at 2:16 PM, Mark Vahrenwald wrote: >> >>> Hi all, >>> I'm in the process of building a Mapnik tile cache from a dataset of >>> shapefiles. The file path to my datasources is hard-coded, and the data >>> itself is broken down in separate folders by state with the state >>> abbreviation as part of the file name (an example file path: >>> "../shapefiles/US/CA/CArivers.shp"). The result of this is that I can >>> render individual states, but I'm not able to render multiple states >>> together because the datasource only allows me to point to one state >>> directory at at time. >>> Given that this is a standard method of file structure for TomTom/Navteq >>> datasets, I'm assuming there's a work-around out there, but I haven't come >>> across it yet. Thanks in advance for any suggestions. >>> Mark >> >> Mark, >> >> Generally if you have more than one shapefile you want to show, then you >> would create another layer definition for that datasource. As mapnik >> supports named styles you would then be able to create one style and apply >> that style to all the layers needed. >> >> If the # of individual shapefiles is enough that creating all those layers >> one by one is overly tedius, then perhaps you could just write a simple >> script to loop through each directory and author the chunk of Mapnik XML >> needed to declare each as a layer. >> >> Generally hundreds of layers in an XML is still quite fast (after the >> initial XML load is finished) because each layer's individual bounding box >> will be cached by mapnik and when rendering only those layers that intersect >> with a tile's extent will be queried. 1000's of layers would also likely >> work fine rendering if you could script the creation of the map document. >> >> Now, if you are using some other tool, like TileMill to author your >> stylesheets, then scripting Mapnik XML is not as straighforward (though in >> the case of TileMill you could script the creation of the mml file which is >> just a JSON version of Mapnik's XML). In this case you might be better off >> scripting the union of a group of shapefiles that all have the same schema >> into one or several larger shapefiles. I would use ogr's --append function >> for this task, but ogr's VRT support could also come in quite handy: >> http://www.gdal.org/ogr/drv_vrt.html >> >> Does that help? >> >> Dane > _______________________________________________ Mapnik-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/mapnik-users
