There's a difference between the extent models used by MapServer and OGC. The WMS code adjusts for that difference so the input extent will definitely see adjustment to account for that. OGC uses the UL corner of the UL pixel and the LR corner of the LR pixel. MapServer uses pixel centers consistently. Do your scale computations account for this difference?
Steve From: [email protected] [mailto:[email protected]] On Behalf Of Peter Hopfgartner Sent: Thursday, July 24, 2014 7:20 AM To: [email protected] Subject: Re: [mapserver-users] WMS Client changes slightly BBOX Hi Worth, thanks for your quick reply. Anyway, the ratio of the extent and of the image seem to match al least up to 10 digits. Playing with the numbers, the error is in the same order of magnitude as if I change image size by one pixel. I would guess, that there is a "off by 1" error somewhere in the MapServer code. Regards, Peter On 07/24/2014 01:30 PM, Worth Lutz wrote: Peter, I have found that if the map size (width and height in pixels) aspect ratio does not exactly match the map extents (map units) aspect ratio the map extents are adjusted. I'm working with MapScript and to get exact scale pdf map I have to set map size first and then extent and then scale to get good results. I hope this helps. Worth Lutz ------------------ On 07/24/2014 06:49 AM, Peter Hopfgartner wrote: I'm generating dynamically Map Object, with with a certain extent, in the concrete example 629396.05065523,4984079.9894638,655192.92565523,5019084.3644638 In generated Map object uses the WMS client functionality to call WMS services. Anyway, the BBOX get's slightly changed, so that the original scale of 1:100000 gets changed to approx 1:100103, since it calls the WMS services with 629382.807906257,4984062.02007212,655206.168404203,5019102.33385548 as can be taken from the web server log files: mmm.mmm.mmm.mmm - - [24/Jul/2014:12:25:58 +0200] "GET /author/services/ows.php?PROJECT=ancitel&MAP=catasto_reti&LANG=xw&OGSTAT=ot3cp0i7qmph4guuof75702m70&RESOLUTION=96&LAYERS=dtm,uso_lombardia,strade_lombardia,g_limiti_amministrativi,g_label,g_0707,g_0704&REQUEST=GetMap&SERVICE=WMS&FORMAT=image/png%3B+mode%3D8bit&STYLES=,,,,,,&HEIGHT=1323&VERSION=1.1.1&SRS=EPSG:32632&WIDTH=975&BBOX=629382.807906257,4984062.02007212,655206.168404203,5019102.33385548&TRANSPARENT=TRUE&EXCEPTIONS=application/vnd.ogc.se_inimage HTTP/1.1" 200 678803 "-" "MapServer/6.4.1 libcurl/7.19.7" This change in scale is beyound te axpected tolerance in this particular use case, where technical data must be plotted in a PDF file. Any help is appreciated. Obvioulsly, I can fetch the WMS services in my code and overlay them "by hand". Anyway, for a couple of reasons this was the preferred approach. Regards, Peter _______________________________________________ mapserver-users mailing list [email protected]<mailto:[email protected]> http://lists.osgeo.org/mailman/listinfo/mapserver-users _______________________________________________ mapserver-users mailing list [email protected]<mailto:[email protected]> http://lists.osgeo.org/mailman/listinfo/mapserver-users -- Peter Hopfgartner R3 GIS Srl - GmbH Via Johann Kravogl-Str. 2 I-39012 Meran/Merano (BZ) web : www.r3-gis.com<http://www.r3-gis.com> mail : [email protected]<mailto:[email protected]> phone: +39 0473 494949 fax : +39 0473 069902 ATTENZIONE! Le informazioni contenute nella presente e-mail e nei documenti eventualmente allegati sono confidenziali. La loro diffusione, distribuzione e/o riproduzione da parte di terzi, senza autorizzazione del mittente è vietata e può violare il D. Lgs. 196/2003. In caso di ricezione per errore, Vogliate immediatamente informare il mittente del messaggio e distruggere la e-mail. ACHTUNG! Die in dieser Nachricht oder in den beigelegten Dokumenten beinhalteten Informationen sind streng vertraulich. Ihre Verbreitung und/oder ihre Wiedergabe durch Dritte ist ohne Erlaubnis des Absenders verboten und verstößt gegen das Legislativdekret 196/2003. Sollten Sie diese Mitteilung irrtümlicherweise erhalten haben, bitten wir Sie uns umgehend zu informieren und anschließend die Mitteilung zu vernichten. WARNING! This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorised copying, disclosure or distribution of the material in this e-mail is strictly forbidden and could be against the law (D. Lgs. 196/2003)
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