Hi, I guess that classification has a big effect in your case. I have been reading that string comparisons are faster than logical ones. How about to have a try by classifying your shapefile and writing the classes directly to a new attribute field? This is my scale dependent group, simplified and spiced with some typos, I fear. LAYER GROUP "Parcels" NAME "all_parcels" TYPE POLYGON STATUS ON DATA "parcels_2008" UNITS METERS MAXSCALEDENOM 100000 CLASS NAME "parcel_class" STYLE OUTLINECOLOR 250 0 180 WIDTH 2 END END METADATA "ows_include_items" "AREA, PERIMETER" "wms_title" "all_parcels" "wms_srs" "EPSG:2393 EPSG:3067 EPSG:4326 EPSG:900913" END PROJECTION "init=epsg:2393" END END LAYER GROUP "Parcels" NAME "ten_percent" TYPE POLYGON STATUS ON DATA "parcels_2008_0" UNITS METERS MAXSCALEDENOM 1000000 MINSCALEDENOM 100000 CLASS NAME "parcel_class" STYLE OUTLINECOLOR 250 0 180 WIDTH 2 END END METADATA "ows_include_items" "AREA, PERIMETER" "wms_title" "ten_percent" "wms_srs" "EPSG:2393 EPSG:3067 EPSG:4326 EPSG:900913" END PROJECTION "init=epsg:2393" END END LAYER GROUP "Parcels" NAME "one_percent" TYPE POLYGON STATUS ON DATA "parcels_2008_00" UNITS METERS MINSCALEDENOM 1000000 CLASS NAME "parcel_class" STYLE # COLOR 240 240 0 OUTLINECOLOR 250 0 180 WIDTH 2 END END METADATA "ows_include_items" "AREA, PERIMETER" "wms_title" "one_percent" "wms_srs" "EPSG:2393 EPSG:3067 EPSG:4326 EPSG:900913" END PROJECTION "init=epsg:2393" END END LAYER -Jukka-
________________________________ Lähettäjä: Chris Jackson [mailto:webturt...@gmail.com] Lähetetty: 3. syyskuuta 2010 12:13 Vastaanottaja: Rahkonen Jukka Kopio: mapserver-users@lists.osgeo.org Aihe: Re: [mapserver-users] Display performance Hi Jukka Thanks for the response and the great investigative work! My log entry for drawing the layer is - [Fri Sep 03 10:01:25 2010].658000 msDrawMap(): Layer 1 (meanspringpeakflow), 24.500s. :o( I do wonder if my Mapfile layer definition is just v.poor (admittedly no expert!) so have taken an excerpt of the layer defintion (there are about 15 classes in all) - views anyone, should I be loading it a different way? Also Jukka, could I get a sample of your scale dependent WMS GROUP layer map code - as it sounds like a great idea maybe for this but also some v.hi-res model grids I am thinking about. Thanks again, much appreciated! Chris LAYER NAME "meanspringpeakflow" TYPE polygon DEBUG 5 DATA "Tide" TEMPLATE void PROJECTION "+proj=utm +zone=31 +ellps=GRS80 +units=m +no_defs" END METADATA "DESCRIPTION" "Mean Spring Peak Flow" "RESULT_FIELDS" "ID,DISTANCE,DEPTH,MEAN_SP_PC" "RESULT_HEADERS" "ID,Minimum Distance (m),Average Depth (m),Mean Spring Peak Flow (m/s)" "ows_title" "meanspringpeakflow" "RESULT_HYPERLINK" "ID|| Load graphing tool" END # Metadata CLASS NAME '> 4.00 (m/s) ' EXPRESSION ([MEAN_SP_PC] >= 4 AND [MEAN_SP_PC] < 4.5) STYLE COLOR 135 99 64 END #end style END # end class CLASS NAME '3.51 - 4.00' EXPRESSION ([MEAN_SP_PC] >= 3.5 AND [MEAN_SP_PC] < 4) STYLE COLOR 158 126 63 END #end style END # end class etc etc On 3 September 2010 09:04, Rahkonen Jukka <jukka.rahko...@mmmtike.fi> wrote: Hi, I took some numbers to compare with. Material and methods Polygon layer, rather simple polygons with few vertises, Feature Count: 117383 DEBUG 5 in mapfile WMS client asks for the whole layer Mapserver 5.2.1 (CGI) on not so fast Windows computer Results First request: rendering time taken from the log file are between 3.5 and 4.5 seconds Following request, BBOX is changing but all the polygons are drawn though: rendering times 1.5 - 2.5 seconds Conclusions and discussion At first one might think that my server is faster. But this test is not controlled at all because we are not using the same shapefiles and we can't say so. What we can say that a couple of hundred of thousand polygons can be drawn faster. However, it does not really make sense to render an image this way if it should be fast. If the screen has 1000 by 1000 pixels it makes a million pixels together. For 200000 polygons it makes 5 pixels per polygon. You can simplify your polygon geometries pretty much before anybody can see the differense. If the polygons are spread evenly nobody can even see the difference if there are 20000 or 200000 polygons on the screen. We have one polygon layer with about million polygons and for that I made two simplified layers which contain only 1 percent and 10 percent of all the polygons. Those and the original shapefile are put into the same scale dependent WMS GROUP layer. This group is pretty fast at any scale. The 1 percent layer is perhaps a bit too sparse but I have been too lazy to have a try with 2 or 5 percent samples. -Jukka Rahkonen-
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