Hi Joel, Could you post that shapefile somewhere or provide a link, pls.
Artem On 14 July 2010 00:11, joel collins <[email protected]> wrote: > Sorry guys, i know i've sent a lot of mail about this. I managed to > get my shapefile loaded into mapserver to try to compare performance, > and the difference is night and day. There is essentially no > noticable lag when viewing the shapefile via mapserver, regardless of > zoom level. > > Do you think i'm doing something wrong that is making mapnik a lot > slower than mapserver? My layer is very simple, just some borders > essentially. Am I better off using a tool like mapserver or geoserver > rather than mapnik for simple layers without much visual pizzaz? > > I am frustrated because the toolsets around mapnik seem much more > modern and easy for me to comprehend (cascadenick, etc), while > mapserver seems more difficult to grasp. > > On Mon, Jul 12, 2010 at 9:42 PM, Dane Springmeyer <[email protected]> wrote: >> >> On Jul 12, 2010, at 6:14 PM, joel collins wrote: >> >>> I realize that my performance will improve using apache / mod_tile, >>> but 0.5 cpu seconds to render a tiny tile is a lot! Even with a 4 >>> core machine this would mean that 8 uncached tile requests per second >>> would max out the CPU. I have kept experimenting and found >>> (obviously, in hindsight), that since my shapefile was not in the >>> google projection, this conversion was being done at runtime. >> >> Yes, reprojection on the fly is very costly, so ensuring the layer srs >> exactly matches the map srs is a critical thing. >> >>> after >>> running ogr2ogr my render time is below 0.2 seconds for zoom level 10. >>> This may have to do... >> >> nice. >> >>> >>> An interesting thing i noticed was when running on windows (osgeo4w >>> installation), mapnik was 2x as slow as mapnik running on an ubuntu VM >>> on the same physical machine! >> >> Make sure you rebuild any indexes for shapefiles on each platform. If that >> does not bring the speeds more closely inline then it would be worthwhile to >> do a bit more digging as they should be comparable. >> >>> >>> On Thu, Jul 8, 2010 at 6:37 PM, Dane Springmeyer <[email protected]> wrote: >>>> >>>> On Jul 7, 2010, at 5:16 PM, joel collins wrote: >>>> >>>>> New mapnik user here, i've made a lot of progress in the last few >>>>> weeks but its been slow going. I am trying to create a tile overlay >>>>> on google maps of some census bureau tiger data (congressional >>>>> district maps in particular) and i have downloaded the associated >>>>> shapefiles (containing polygons only, no markers or other data types). >>>>> >>>>> For a web server I am currently just using Tilelight (mapnik-utils) >>>>> for development, and although i'm planning on using a different >>>>> configuration in production, i'm seeing very poor performance during >>>>> tile generation. >>>> >>>> That's because the 'liteserv.py' script is only for development, and >>>> deployment targets multicore architectures only (mod_wsgi with N processes >>>> = number of cores). >>>> >>>> Although I too find that python's wsgiref server implementation (that >>>> liteserv.py) uses is very slow. You can get about double the speed with >>>> other development servers that implement the WSGI standard, one being >>>> werkzeug. In fact, just the other day I added support for werkzeug: >>>> >>>> http://bitbucket.org/springmeyer/tilelite/changeset/e2335783f42c >>>> >>>> But, again the faster deployment for TileLite is with mod_wsgi inside >>>> Apache. >>>> >>>> And faster again will be a multithreaded server like mod_tile. >>>> >>>>> On my google maps, for example, when i scroll to a >>>>> new area or change zoom levels it can often take 15 seconds for the >>>>> new tiles to appear (this is especially slow because there are about a >>>>> dozen simultaneous tile requests that queue up). >>>> >>>> That's because you are running a single-threaded, single-process >>>> development server that is only for development. >>>> >>>>> I realize that on a >>>>> multi-core production machine this wont be so bad but it still seems >>>>> very slow. >>>>> >>>>> When I render a single tile, it still takes between 0.5-3 seconds. I >>>>> have tried loading the shapes into postgres but that actually resulted >>>>> in worse performance (5 seconds), although I may have configured >>>>> something wrong. Some rudimentary math tells me that I wont be able >>>>> to pre-render all tiles (we would like to be able to show street-level >>>>> zooming in google maps, around 16 or 17), so we will need to have the >>>>> ability to render tiles that haven't been pre-rendered fast enough for >>>>> real time browsing. Also, using something like TileCache will help of >>>>> course but at the end of the day new tiles still need to be rendered. >>>>> >>>>> My questions are: >>>>> What kind of response times should I expect from mapnik for creating >>>>> tiles from shapefiles? >>>>> >>>>> What can be done to speed up the rendering? Should I be downsampling >>>>> the number of data points in the shape files? We like the high level >>>>> of accuracy that we see in the tiger files but maybe thats what is >>>>> slowing this down? >>>>> >>>>> Is leaving the data in shapefiles the appropriate approach? (I was >>>>> planning on using postgis so i could do other queries like see which >>>>> polygons touch, find what polygons are near a lat/long, etc) >>>>> >>>>> Thanks! >>>>> _______________________________________________ >>>>> Mapnik-users mailing list >>>>> [email protected] >>>>> https://lists.berlios.de/mailman/listinfo/mapnik-users >>>> >>>> >> >> > _______________________________________________ > Mapnik-users mailing list > [email protected] > https://lists.berlios.de/mailman/listinfo/mapnik-users > _______________________________________________ Mapnik-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/mapnik-users
