PERL/Mapscript postGIS examples?
Stephen Davies
sdc at SDC.COM.AU
Tue Mar 21 17:40:58 EST 2006
G'day Eric.
The probe table has the usual postGIS SRID constraint limiting it to
4283 and geometry_columns has the same value.
The area in question is actually in zone 54 and the ecw image is
referenced that way but the individual layer projections seem to handle
that fine. The probe points are correctly positioned on the image.
The original
(At one stage I tried changing the probe layer projection to 4284. That
must have still been in the mapfile you saw. Now it has 4283.)
The data was input as lat/long.
I would have thought that any issue arising between 4283 and 4284 would
affect longitude rather than latitude.
Cheers,
Stephen
On Wednesday 22 March 2006 00:23, Eric Bridger wrote:
> I think the question is what does postgis think the srid is?
>
> select srid from geometry_columns where f_table_name = 'probe';
>
> On Mon, 2006-03-20 at 20:55, Stephen Davies wrote:
> > Good pick Eric.
> >
> > I did as you suggested and changed the projection to "latlong" and
> > it worked - from mapscript and from CGI mapserv.
> >
> > (The extent is passed in as args in both cases. That's why you
> > don't see an extent statement in the mapfile.)
> >
> > The question now has to be why?
> > I only changed the one line - well replaced two with one.
> >
> > I then replaced the original PROJ entries in the mapfile and called
> > setProjection("proj=latlong"); in the PERL and it worked again.
> >
> > The original eqc projection still works with CGI mapserv.
> >
> > What is different with mapscript?
> >
> > Cheers and thanks,
> > Stephen
> >
> > On Tuesday 21 March 2006 08:32, Eric Bridger wrote:
> > > Not sure why this would work in CGI mode.
> > > shp2img is the best tool for debugging postgis layers. Well,
> > > turning on postgres logging works as well.
> > >
> > > Just a guess but I suspect a projection issue.
> > >
> > > Does your postgis data really have an SRID of 4284? You many
> > > need to change your DATA statement in the postgis layer to
> > > something like: DATA "the_geom (select * from probe) using unique
> > > oid using SRID=4284"
> > >
> > > The postgis queries below look like they are attempting to use
> > > the standard SRID of -1 or lat/lon projection.
> > >
> > > Also I don't see any EXTENT in your map file. That should throw
> > > an error.
> > >
> > > I would try getting it all to work with no projection
> > > (proj=latlong or EPGS:4326) first then start messing with the
> > > projections.
> > >
> > > Eric
> > >
> > > On Sat, 2006-03-18 at 01:15, Stephen Davies wrote:
> > > > Thanks for the feedback.
> > > >
> > > > Turning on PostgreSQL logging did indeed reveal more
> > > > information. However, it leaves even more confused than before.
> > > >
> > > > It seems that the underlying cause of my results is that the
> > > > extent being used by mapscript bears no relation to the extent
> > > > that I specified.
> > > >
> > > > Here is the sql statement generated from mapscript:
> > > >
> > > > 2006-03-18 16:22:47 CST LOG: 00000: duration: 33.759 ms
> > > > statement: DECLARE mycursor BINARY CURSOR FOR SELECT
> > > >
> > > >
location::text,asbinary(force_collection(force_2d(geom)),'NDR'),id:
> > > >:text from probe WHERE geom && setSRID('BOX3D(139.522253226183
> > > >
> > > > -0.000314231148091942,139.522253452601
> > > > -0.000314003203767908)'::BOX3D, find_srid('','probe','geom') )
> > > >
> > > > The actual extent specified (and the one that works from CGI
> > > > mapserv) was:
> > > >
> > > > 139.5143351 -34.7459112 139.5278707 -34.7207064
> > > >
> > > > The "correct" query as generated by a CGI call with the above
> > > > mapext is:
> > > >
> > > > 2006-03-18 16:11:57 CST LOG: 00000: duration: 33.703 ms
> > > > statement: DECLARE mycursor BINARY CURSOR FOR SELECT
> > > > location::text,asbinary(force_collection(force_2d
> > > > (geom)),'NDR'),id::text from probe WHERE geom &&
> > > > setSRID('BOX3D(139.508530404246
> > > > -34.7456930137356,139.533675395754 -34.7204885334377)'::BOX3D,
> > > > find_srid('','probe','geom') )
> > > >
> > > > Again the extent is changed but nowhere as drastically.
> > > >
> > > > I then tried hard-wiring the extent into the map file and
> > > > removing the mapext argument from the CGI call and got the same
> > > > result and the same query.
> > > >
> > > > I then modified my PERL script to use the extent in the map
> > > > file and again got the same result and the same query
> > > > generated.
> > > >
> > > > It looks as if the mapscript setExtent method does something
> > > > strange and different from the CGI mapext option and that both
> > > > do strange things with extent statements in map files in some
> > > > circumstances.
> > > >
> > > > I tried changing the UNITS to DD but this made no difference
> > > > (METERS is required to make reference maps etc work properly in
> > > > the CGI world.)
> > > >
> > > > Cheers,
> > > > Stephen
> > > >
> > > > On Friday 17 March 2006 23:42, Simpson wrote:
> > > > > Stephen,
> > > > >
> > > > > You might try checking the Postgresql logs to see if
> > > > > Mapserver is connecting and requesting data. Turn on
> > > > > statement logging in Postgresql config to get details of
> > > > > exactly what is being sent. You can then run the statement
> > > > > from psql to see if it is returning what you expect.
> > > > >
> > > > > Drew.
> > > > >
> > > > > -----Original Message-----
> > > > > From: UMN MapServer Users List
> > > > > [mailto:MAPSERVER-USERS at LISTS.UMN.EDU]On Behalf Of Stephen
> > > > > Davies Sent: Friday, March 17, 2006 12:48 AM
> > > > > To: MAPSERVER-USERS at LISTS.UMN.EDU
> > > > > Subject: [UMN_MAPSERVER-USERS] PERL/Mapscript postGIS
> > > > > examples?
> > > > >
> > > > >
> > > > > Could somebody please send me or point me at an example of a
> > > > > PERL/Mapscript script that displays layers populated from a
> > > > > postGIS database and/or raster layers?
> > > > > The following PERL/Mapscript and map file generates an image
> > > > > containing only the copyright layer.
> > > > > Exactly the same map file with mapserver invoked as CGI
> > > > > generates all layers.
> > > > > (In both cases the extent is provided as args.
> > > > > eg ./genpics q 1 jpg 139.5143351 -34.7459112 139.5278707
> > > > > -34.7207064)
> > > > >
> > > > > Cheers and thanks,
> > > > > Stephen Davies
> > > > >
> > > > > #! /usr/bin/perl
> > > > > #
> > > > > # args are UID (for mapfile), pic sequence #, image type
> > > > > (extension), extent
> > > > > #
> > > > > use strict;
> > > > > #use CGI;
> > > > > use mapscript;
> > > > > my $uno = $ARGV[0];
> > > > > my $seq = $ARGV[1];
> > > > > my $ext = $ARGV[2];
> > > > > my $minx = $ARGV[3];
> > > > > my $miny = $ARGV[4];
> > > > > my $maxx = $ARGV[5];
> > > > > my $maxy = $ARGV[6];
> > > > > #
> > > > > # if sequence = 1, create/empty directory (ignoring errors)
> > > > > #
> > > > > if ($seq == 1){
> > > > > mkdir("/var/www/html/status_images/$uno",0777);
> > > > > unlink </var/www/html/status_images/$uno/*>;
> > > > > }
> > > > > #
> > > > > my $mapfile = "/tmp/$uno.map";
> > > > > my $map = mapscript::mapObj->new($mapfile);
> > > > > my $i=$map->setExtent($minx,$miny,$maxx,$maxy);
> > > > > #
> > > > > #my $img = $map->prepareImage();
> > > > > my $img = $map->draw();
> > > > > my $fname = "/var/www/html/status_images/$uno/$seq.$ext";
> > > > > $img->save($fname);
> > > > > ===================================================
> > > > > MAP
> > > > > NAME perltest
> > > > >
> > > > >
> > > > > PROJECTION
> > > > > "proj=eqc"
> > > > > "lon_0=139.521e"
> > > > > END
> > > > >
> > > > > SIZE 600 600
> > > > > FONTSET "/var/www/html/benparts/fonts.list"
> > > > > SYMBOLSET "/var/www/html/benparts/symbols"
> > > > > UNITS METERS
> > > > > IMAGETYPE jpeg
> > > > > OUTPUTFORMAT
> > > > > NAME jpeg
> > > > > DRIVER "GD/JPEG"
> > > > > MIMETYPE "image/jpeg"
> > > > > IMAGEMODE RGB
> > > > > EXTENSION "jpg"
> > > > > FORMATOPTION "QUALITY=75"
> > > > > END
> > > > > IMAGECOLOR 255 255 255
> > > > >
> > > > > WEB
> > > > > template /var/www/html/benparts/templates/test1.html
> > > > > imagepath "/var/www/html/tmp/"
> > > > > imageurl "/tmp/"
> > > > > END
> > > > >
> > > > > LAYER
> > > > > TYPE RASTER
> > > > > NAME "bkgrnd"
> > > > > STATUS DEFAULT
> > > > > PROJECTION
> > > > > "init=epsg:28354"
> > > > > END
> > > > > DATA "/var/www/html/benparts/rasters/walker.ecw"
> > > > > # OFFSITE 0 0 0
> > > > > PROCESSING "DITHER=YES"
> > > > > END
> > > > >
> > > > > LAYER
> > > > > CONNECTIONTYPE postgis
> > > > > NAME "probe"
> > > > > DATA "geom from probe"
> > > > > CONNECTION "user=scldad dbname=benparts"
> > > > > STATUS DEFAULT
> > > > > TYPE POINT
> > > > > # FILTER "id in (0)"
> > > > > PROJECTION
> > > > > "init=epsg:4284"
> > > > > END
> > > > > MAXSCALE 5000000
> > > > > LABELITEM "location"
> > > > > CLASS
> > > > > NAME "Probe (Right Click to select)"
> > > > > STYLE
> > > > > COLOR 0 214 0
> > > > > SYMBOL 'circle'
> > > > > SIZE 7
> > > > > END
> > > > > LABEL
> > > > > MINDISTANCE 15
> > > > > POSITION CR
> > > > > SIZE SMALL
> > > > > COLOR 0 0 0
> > > > > FORCE TRUE
> > > > > END
> > > > > END
> > > > > END
> > > > >
> > > > > LAYER
> > > > > NAME 'copyright'
> > > > > TYPE ANNOTATION
> > > > > STATUS DEFAULT
> > > > > TRANSFORM FALSE # coordinates are in pixels
> > > > > FEATURE
> > > > > POINTS 10 595 END
> > > > > END
> > > > > CLASS
> > > > > LABEL
> > > > > TYPE TRUETYPE
> > > > > FONT arial
> > > > > SIZE 8
> > > > > COLOR 255 0 0
> > > > > POSITION CR
> > > > > END
> > > > > TEXT 'Photography supplied by MAPLAND, Environment
> > > > > Information, Dept Environment & Heritage'
> > > > > END
> > > > > END
> > > > > END
> > > > > --
> > > > > =============================================================
> > > > >==== ==== === This email is for the person(s) identified
> > > > > above, and is confidential to the sender and the person(s).
> > > > > No one else is authorised to use or disseminate this email or
> > > > > its contents.
> > > > >
> > > > > Stephen Davies Consulting Voice:
> > > > > 08-8177 1595 Adelaide, South Australia.
> > > > > Fax: 08-8177 0133 Computing & Network solutions.
> > > > > Mobile:0403 0405 83
> > > >
> > > > --
> > > > ===============================================================
> > > >==== ===== This email is for the person(s) identified above, and
> > > > is confidential to the sender and the person(s). No one else
> > > > is authorised to use or disseminate this email or its contents.
> > > >
> > > > Stephen Davies Consulting Voice:
> > > > 08-8177 1595 Adelaide, South Australia.
> > > > Fax: 08-8177 0133 Computing & Network solutions.
> > > > Mobile:0403 0405 83
> >
> > --
> > ===================================================================
> >===== This email is for the person(s) identified above, and is
> > confidential to the sender and the person(s). No one else is
> > authorised to use or disseminate this email or its contents.
> >
> > Stephen Davies Consulting Voice: 08-8177
> > 1595 Adelaide, South Australia. Fax:
> > 08-8177 0133 Computing & Network solutions.
> > Mobile:0403 0405 83
--
=======================================================================
This email is for the person(s) identified above, and is confidential to
the sender and the person(s). No one else is authorised to use or
disseminate this email or its contents.
Stephen Davies Consulting Voice: 08-8177 1595
Adelaide, South Australia. Fax: 08-8177 0133
Computing & Network solutions. Mobile:0403 0405 83
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