How to show lines between PostGIS data of type POINT

[Russ Bradford]

Thanks Steve,

I have been working through the workshop and have it the most helpful
reference/tutorial yet. I will try to implement the suggestions below.
By the way, I have my data as both point and lat/long columns (could not
figure out how to use just lat/long - newbie).

Cheers and many thanks, Russ.

-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On
Behalf Of Stephen Woodbridge
Sent: Wednesday, 9 November 2005 3:24 PM
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: Re: [UMN_MAPSERVER-USERS] How to show lines between PostGIS
data of type POINT


Hi Russ,

Have you looked at
http://ms.gis.umn.edu/community/conferences/MUM3/workshop/postgis/

this is a great intro to PostGIS and mapserver.

If your points are in a table as point geometry (as apposed to a lat and

lon column) then you can doe something like:

select setsrid(makeline((select the_geom from points order by id)),
4326);

if you data is in lat, lon columns then:

select setsrid(
          makeline(
            (select setsrid(
                      makepoint(log,lat), 4326
                    )
               from points order by id
             )
          ), 4326
        );

you may need to change the SRID from 4326 to whatever your data is in.

-Steve

Russ Bradford wrote:
> Hi list,
> I too have a database filled with point data for which I would like to

> "join-the-dots". Would anyone have a working example of how to do this

> using MapServer and PostgreSQL that they would like to share? The 
> original thread here mentioned looking into Collect(), MakeLine() and 
> AddPoint(). I have searched through the documentation and come up 
> blank with all except Collect(). And being very new to MapServer (and 
> PostgreSQL) I would like a little more direction in how to apply these

> solutions. If it makes any difference, I am using a Windows machine 
> with Apache and the latest version of Mapserver. Cheers, Russ.
> 
> 
> On Tue, 26 Jul 2005 08:50:52 -0500, David Bitner 
> <osgis.lists at GMAIL.COM>
> wrote:
> 
> 
>>To show lines but query points, you would need to have your data in 
>>Mapserver as both lines and points.  To convert your points to lines 
>>in Postgis (can be done on the fly) look into Collect(), MakeLine(), 
>>and AddPoint().  You'll need to be sure to order your points by 
>>timestamp before aggregating them to the line.
>>
>>On 7/26/05, Sebastian Albrecht <albrecht at fielax.de> wrote:
>>
>>>Hello,
>>>
>>>is it possible to show lines between POINT data results from a 
>>>PostGIS-DB? Is it possible to somehow convert one point and the next 
>>>one following to a line on-the-fly each time the Mapserver queries 
>>>the database?
>>>
>>>My problem is I have a lot of single latlon points which have 
>>>different timestamps and further values. The user should be able to 
>>>query these values of a single point but lines should be shown in the

>>>map. Using a LINE type would not be very consistent because the user 
>>>would not know which end of the line is the point the values belong 
>>>to.
>>>
>>>One knows something? ;)
>>>
>>>Best regards,
>>>Sebastian
>>>
> 
>