<HTML dir=ltr><HEAD><TITLE>RE: [postgis-users] Possible function to convert +-180featuresto0-360 longitudes</TITLE>
<META http-equiv=Content-Type content="text/html; charset=unicode">
<META content="MSHTML 6.00.2900.3354" name=GENERATOR></HEAD>
<BODY>
<DIV id=idOWAReplyText42996 dir=ltr>
<DIV dir=ltr><FONT face=Arial color=#000000 size=2>Stan,</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>I know I look like a command line glutton, but I use PgAdmin III a lot and actually that's how I read the comments.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>In the right hand pane on the properties pane at the very bottom is a field that displays the comments. That's what got me thinking - shame PostGIS functions have no comments - now I've got to leave my screen to go find the definition in the manual which tells me a convex hull is a convex hull. </FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>I was wondering about the arcane not referencing variables by there names in the args list. That was another thing that drives me a tad bit nuts, so I'm glad you mentioned it.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>Paul,</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>Does this mean also that we definition committers can come up with more meaningful comments that a lay user has a chance of understanding - instead of </FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>ST_ConvexHull -- <FONT face="Times New Roman" size=3>Return the convex hull of the ST_Geometry value.</FONT></FONT></DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr>Sorry for nit-picking. I know REAL GIS users already know what a convex hull is.</DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr>Thanks,</DIV>
<DIV dir=ltr>Regina</DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV></DIV>
<DIV dir=ltr><BR>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> postgis-users-bounces@postgis.refractions.net on behalf of Sufficool, Stanley<BR><B>Sent:</B> Fri 6/20/2008 11:31 AM<BR><B>To:</B> PostGIS Users Discussion<BR><B>Subject:</B> RE: [postgis-users] Possible function to convert +-180featuresto0-360 longitudes<BR></FONT><BR></DIV>
<DIV>
<P><FONT size=2>Is there a way to get the comments to show in pgAdmin when clicking<BR>through the functions? This would be OH SO helpful.<BR><BR>I'm forced to use SQL Server 2005 daily, but the one thing I see SQL<BR>having is NAMED arguments to procedures and functions. I know PG deals<BR>with this differently. However, if the code/comments could provide a<BR>clue as to the arguments that a function receives and produces, this<BR>would be very helpful.<BR><BR>> -----Original Message-----<BR>> From: postgis-users-bounces@postgis.refractions.net<BR>> [<A href="mailto:postgis-users-bounces@postgis.refractions.net">mailto:postgis-users-bounces@postgis.refractions.net</A>] On<BR>> Behalf Of Obe, Regina<BR>> Sent: Friday, June 20, 2008 5:25 AM<BR>> To: PostGIS Users Discussion<BR>> Subject: RE: [postgis-users] Possible function to convert<BR>> +-180 featuresto0-360 longitudes<BR>><BR>><BR>> Paul,<BR>><BR>> I don't see this function defined in the docs. Am I missing<BR>> where it is.<BR>><BR>> Also I was thinking - would be nice if when we built all<BR>> these functions we put comments as to what they do in the<BR>> comments metadata section of postgres. It would have 2<BR>> positive effects<BR>><BR>> 1) When I'm scanning thru the functions in my database as I<BR>> normally do<BR>> - I would know what it does and probably how to use it<BR>> without having to refer to the manual<BR>><BR>> 2)<BR>> I imagine it would also make auto-generation of documentation<BR>> a bit easier too. Example<BR>><BR>> CREATE OR REPLACE FUNCTION st_shift_longitude(geometry)<BR>> RETURNS geometry AS<BR>> '$libdir/liblwgeom', 'LWGEOM_longitude_shift'<BR>> LANGUAGE 'c' IMMUTABLE STRICT;<BR>> COMMENT ON FUNCTION st_shift_longitude(geometry) IS 'Reads<BR>> every point/vertex in every component of every feature in a<BR>> geometry, and if the longitude coordinate is <0, adds 360 to<BR>> it. The result would be a 0-360 version of the data to be<BR>> plotted in a 180 centric map';<BR>><BR>><BR>> Just my two cents,<BR>> Regina<BR>><BR>><BR>> -----Original Message-----<BR>> From: postgis-users-bounces@postgis.refractions.net<BR>> [<A href="mailto:postgis-users-bounces@postgis.refractions.net">mailto:postgis-users-bounces@postgis.refractions.net</A>] On<BR>> Behalf Of Paul Ramsey<BR>> Sent: Friday, June 20, 2008 2:47 AM<BR>> To: pcreso@pcreso.com; PostGIS Users Discussion<BR>> Subject: Re: [postgis-users] Possible function to convert<BR>> +-180 features to0-360 longitudes<BR>><BR>> ST_Shift_Longitude?<BR>><BR>> On Fri, Jun 20, 2008 at 5:52 AM, <pcreso@pcreso.com> wrote:<BR>> > Hi,<BR>> ><BR>> > I believe such a function is feasible, but my programming skills are<BR>> pretty minimal, so any advice appreciated.<BR>> ><BR>> > I have data in a custom mercator projection, crossing 180 degrees. I<BR>> can use ST_transform to generate a lat/long (EPSG:4326)<BR>> version, but only in a +-180 longtitudinal space, which<BR>> results in features at each side of a map with lines joining<BR>> them running across the map.<BR>> ><BR>> > It seems feasible to have a function (to360 ?) which reads every<BR>> point/vertex in every component of every feature in a<BR>> geometry column, & if the longitude coordinate is <0, adds<BR>> 360 to it. The result would be a 0-360 version of the data to<BR>> be plotted in a 180 centric map.<BR>> ><BR>> > Given the original data was not split at 180, this should simply<BR>> rebuild the correct topology of the features. I'm not looking<BR>> to split or join features which cross the 180 or 0 longitude lines.<BR>> ><BR>> > So, am I wrong in any of my assumptions, & if not, can<BR>> anyone point me<BR>> to some relevant examples to learn from or suggest how I<BR>> should go about writing such a function?<BR>> ><BR>> ><BR>> > Thanks,<BR>> ><BR>> > Brent Wood<BR>> > _______________________________________________<BR>> > postgis-users mailing list postgis-users@postgis.refractions.net<BR>> > <A href="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR>> ><BR>> _______________________________________________<BR>> postgis-users mailing list postgis-users@postgis.refractions.net<BR>> <A href="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR>> -----------------------------------------<BR>> The substance of this message, including any attachments, may<BR>> be confidential, legally privileged and/or exempt from<BR>> disclosure pursuant to Massachusetts law. It is intended<BR>> solely for the addressee. If you received this in error,<BR>> please contact the sender and delete the material from any computer.<BR>><BR>> _______________________________________________<BR>> postgis-users mailing list postgis-users@postgis.refractions.net<BR>> <A href="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR>><BR>_______________________________________________<BR>postgis-users mailing list<BR>postgis-users@postgis.refractions.net<BR><A href="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR></FONT></P></DIV></BODY></HTML>