Damiano, What mapnik and proj versions are you running?
Also, what happens if you take your two comparison mapfiles and strip all the projection information from each and then run the speed tests again? Mapnik will assume both mapfiles and the corresponding datasets are in WGS 84/4326 (and of course the outputs of the google mercator will be screwy), but it would be interesting to see if the time lag still exists. That would help dispel the possibility that mapnik is attempting any reprojection. I also wonder whether the z-order of the reprojected shapefiles was changed during ogr2ogr reprojection and if that might affect render speeds at all? Dane On Nov 29, 2008, at 12:35 AM, Damiano Morosi wrote: > Hi all, > > I have the following situation: a set of shapefiles in long/lat and > the same shapefiles reprojected using ogr2ogr, with 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 [EMAIL PROTECTED] +no_defs". When rendering the > two mapfiles (one using the original shapes and the other using the > projected shapes), I noticed that the rendering time, acoording to > nik2img (and tilecache, too) double. The nik2img tool produce quite > the same output until step 35, and then in step 36 (rendering) the > time used change. If run in dry mode with -n, the two maps require > the same time. > The two images produced by nik2img are 60k (original) and 74k > (projected), but to me seems strange that a +14k image size lead to > a double in rendering time. > These are the mapfiles I used: > > ORIGINAL > --- > <?xml version="1.0" encoding="utf-8"?> > <Map srs="+proj=latlong +datum=WGS84" bgcolor="#F1EEF2"> > <Style name="My Style"> > <Rule> > <PolygonSymbolizer> > <CssParameter name="fill">#f2eff9</CssParameter> > </PolygonSymbolizer> > <LineSymbolizer> > <CssParameter name="stroke">#808080</CssParameter> > <CssParameter name="stroke-width">0.1</CssParameter> > </LineSymbolizer> > </Rule> > </Style> > <Style name="Green Areas"> > <Rule> > <PolygonSymbolizer> > <CssParameter name="fill">#B6FCB6</CssParameter> > </PolygonSymbolizer> > </Rule> > </Style> > <Style name="Water"> > <Rule> > <PolygonSymbolizer> > <CssParameter name="fill">#B5D0D0</CssParameter> > </PolygonSymbolizer> > </Rule> > </Style> > <Style name="Major Highways"> > <Rule> > <MaxScaleDenominator>6000000</MaxScaleDenominator> > <LineSymbolizer> > <CssParameter name="stroke">#809BC0</CssParameter> > <CssParameter name="stroke-width">.4</CssParameter> > </LineSymbolizer> > </Rule> > </Style> > <Style name="Secondary Highways"> > <Rule> > <MaxScaleDenominator>185000</MaxScaleDenominator> > <LineSymbolizer> > <CssParameter name="stroke">#EB9A9B</CssParameter> > <CssParameter name="stroke-width">.2</CssParameter> > </LineSymbolizer> > </Rule> > </Style> > <Style name="Streets 4"> > <Rule> > <MaxScaleDenominator>70000</MaxScaleDenominator> > <LineSymbolizer> > <CssParameter name="stroke">#FDCC8B</CssParameter> > <CssParameter name="stroke-width">.2</CssParameter> > </LineSymbolizer> > </Rule> > </Style> > <Style name="Streets 5"> > <Rule> > <MaxScaleDenominator>70000</MaxScaleDenominator> > <LineSymbolizer> > <CssParameter name="stroke">#C0C0C0</CssParameter> > <CssParameter name="stroke-width">.2</CssParameter> > </LineSymbolizer> > </Rule> > </Style> > > > > > <Layer name="green" srs="+proj=latlong +datum=WGS84" status="1" > clear_label_cache="0"> > <StyleName>Green Areas</StyleName> > <Datasource> > <Parameter name="file">/var/www/shapes/LandUseA</ > Parameter> > <Parameter name="type">shape</Parameter> > </Datasource> > </Layer> > <Layer name="water" srs="+proj=latlong +datum=WGS84" status="1" > clear_label_cache="0"> > <StyleName>Water</StyleName> > <Datasource> > <Parameter name="file">/var/www/shapes/WaterPoly</ > Parameter> > <Parameter name="type">shape</Parameter> > </Datasource> > </Layer> > <Layer name="streets_5" srs="+proj=latlong +datum=WGS84" > status="1" clear_label_cache="0"> > <StyleName>Streets 5</StyleName> > <Datasource> > <Parameter name="file">/var/www/shapes/Streets5/Streets</ > Parameter> > <Parameter name="type">shape</Parameter> > </Datasource> > </Layer> > <Layer name="streets_4" srs="+proj=latlong +datum=WGS84" > status="1" clear_label_cache="0"> > <StyleName>Streets 4</StyleName> > <Datasource> > <Parameter name="file">/var/www/shapes/Streets4/Streets</ > Parameter> > <Parameter name="type">shape</Parameter> > </Datasource> > </Layer> > <Layer name="secHigh" srs="+proj=latlong +datum=WGS84" > status="1" clear_label_cache="0"> > <StyleName>Secondary Highways</StyleName> > <Datasource> > <Parameter name="file">/var/www/shapes/SecHwys</Parameter> > <Parameter name="type">shape</Parameter> > </Datasource> > </Layer> > <Layer name="majHigh" srs="+proj=latlong +datum=WGS84" > status="1" clear_label_cache="0"> > <StyleName>Major Highways</StyleName> > <Datasource> > <Parameter name="file">/var/www/shapes/MajHwys</Parameter> > <Parameter name="type">shape</Parameter> > </Datasource> > </Layer> > > </Map> > --- > > PROJECTED SHAPES > --- > <?xml version="1.0" encoding="utf-8"?> > <Map srs="+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 [EMAIL PROTECTED] +no_defs" > bgcolor="#F1EEF2"> > <Style name="My Style"> > <Rule> > <PolygonSymbolizer> > <CssParameter name="fill">#f2eff9</CssParameter> > </PolygonSymbolizer> > <LineSymbolizer> > <CssParameter name="stroke">#808080</CssParameter> > <CssParameter name="stroke-width">0.1</CssParameter> > </LineSymbolizer> > </Rule> > </Style> > <Style name="Green Areas"> > <Rule> > <PolygonSymbolizer> > <CssParameter name="fill">#B6FCB6</CssParameter> > </PolygonSymbolizer> > </Rule> > </Style> > <Style name="Water"> > <Rule> > <PolygonSymbolizer> > <CssParameter name="fill">#B5D0D0</CssParameter> > </PolygonSymbolizer> > </Rule> > </Style> > <Style name="Major Highways"> > <Rule> > <MaxScaleDenominator>6000000</MaxScaleDenominator> > <LineSymbolizer> > <CssParameter name="stroke">#809BC0</CssParameter> > <CssParameter name="stroke-width">.4</CssParameter> > </LineSymbolizer> > </Rule> > </Style> > <Style name="Secondary Highways"> > <Rule> > <MaxScaleDenominator>185000</MaxScaleDenominator> > <LineSymbolizer> > <CssParameter name="stroke">#EB9A9B</CssParameter> > <CssParameter name="stroke-width">.2</CssParameter> > </LineSymbolizer> > </Rule> > </Style> > <Style name="Streets 4"> > <Rule> > <MaxScaleDenominator>70000</MaxScaleDenominator> > <LineSymbolizer> > <CssParameter name="stroke">#FDCC8B</CssParameter> > <CssParameter name="stroke-width">.2</CssParameter> > </LineSymbolizer> > </Rule> > </Style> > <Style name="Streets 5"> > <Rule> > <MaxScaleDenominator>70000</MaxScaleDenominator> > <LineSymbolizer> > <CssParameter name="stroke">#C0C0C0</CssParameter> > <CssParameter name="stroke-width">.2</CssParameter> > </LineSymbolizer> > </Rule> > </Style> > > > > > <Layer name="green" srs="+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 > [EMAIL PROTECTED] +no_defs" bgcolor="#F1EEF2" status="1" > clear_label_cache="0"> > <StyleName>Green Areas</StyleName> > <Datasource> > <Parameter name="file">/var/www/shapes/proj/LandUseA</ > Parameter> > <Parameter name="type">shape</Parameter> > </Datasource> > </Layer> > <Layer name="water" srs="+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 > [EMAIL PROTECTED] +no_defs" bgcolor="#F1EEF2" status="1" > clear_label_cache="0"> > <StyleName>Water</StyleName> > <Datasource> > <Parameter name="file">/var/www/shapes/proj/WaterPoly</ > Parameter> > <Parameter name="type">shape</Parameter> > </Datasource> > </Layer> > <Layer name="streets_5" srs="+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 > [EMAIL PROTECTED] +no_defs" bgcolor="#F1EEF2" status="1" > clear_label_cache="0"> > <StyleName>Streets 5</StyleName> > <Datasource> > <Parameter name="file">/var/www/shapes/proj/Streets5</ > Parameter> > <Parameter name="type">shape</Parameter> > </Datasource> > </Layer> > <Layer name="streets_4" srs="+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 > [EMAIL PROTECTED] +no_defs" bgcolor="#F1EEF2" status="1" > clear_label_cache="0"> > <StyleName>Streets 4</StyleName> > <Datasource> > <Parameter name="file">/var/www/shapes/proj/Streets4</ > Parameter> > <Parameter name="type">shape</Parameter> > </Datasource> > </Layer> > <Layer name="secHigh" srs="+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 > [EMAIL PROTECTED] +no_defs" bgcolor="#F1EEF2" status="1" > clear_label_cache="0"> > <StyleName>Secondary Highways</StyleName> > <Datasource> > <Parameter name="file">/var/www/shapes/proj/SecHwys</ > Parameter> > <Parameter name="type">shape</Parameter> > </Datasource> > </Layer> > <Layer name="majHigh" srs="+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 > [EMAIL PROTECTED] +no_defs" bgcolor="#F1EEF2" status="1" > clear_label_cache="0"> > <StyleName>Major Highways</StyleName> > <Datasource> > <Parameter name="file">/var/www/shapes/proj/MajHwys</ > Parameter> > <Parameter name="type">shape</Parameter> > </Datasource> > </Layer> > > </Map> > --- > > Thank you all, > > Damiano > _______________________________________________ > 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
