Re: Help with storing spatial (map coordinates) data?

Thanks Greg,

I don't know in practice if I will need the minutes and seconds, as you
say degrees with decimal information is probably more accurate. If I
store degrees in decimal I will need to convert back and forth though as
people will use GPS to enter lat and long into the system. I need to be
able to work out route lengths for various transport modes as well as
integrating (in the future) with GIS mapping software such as ESRi or
MapInfo.

I have subscribed to the Open Geospatial Consortium and downloaded their
"common architecture" which includes an SQL model... But it is a lot to
take in, so any guidance is appreciated.

Thanks and regards

John

Gregory S. Williamson wrote:
> We have had good success with postGIS for storing various spatial data sets (polygons, points and lines).
>
> They can be found at <http://postgis.refractions.net/>.
>
> We store our data in lat/long but postGIS has many different spatial reference systems defined and I would suspect
thatminutes/seconds exists. You may want to subscribe to and post your question on the postGIS mailing list. 
>
> There are windows-ready compiled versions which seem to work well, although I've only played with them for prototypes
(ourreal database servers are all linux so I can't be of any help on the Windoze front). 
>
> In general support for this extension of postgres is quite helpful, so I would suggest asking on their general list.
>
> HTH,
>
> Greg Williamson
> DBA
> GlobeXplorer LLC
>
> -----Original Message-----
> From:    pgsql-general-owner@postgresql.org on behalf of John Tregea
> Sent:    Sun 6/11/2006 11:18 PM
> To:    pgsql-general@postgresql.org
> Cc:
> Subject:    [GENERAL] Help with storing spatial (map coordinates) data?
>
> Hi,
>
> I have recently switched to PostgreSQL and had no problem bringing our
> existing (my)SQL databases and data into the environment. I am now
> extending the functionality of our databases and want to start storing
> spatial information.
>
> The information is made up of latitude and longitude coordinates that
> define a point or location on the earth's surface. e.g. degrees, minutes
> and seconds north/south and degrees, minutes and seconds east/west.
>
> I have read up on custom data types (with input and output functions) in
> the docs but am not sure if that is the best way to go. Can anyone point
> me to a simple, workable implementation of storing and managing this
> type of data or advise me on how to structure a series of fields that
> could combine to the required string?
>
> I am running postgreSQL 8.1.4 under WinXP Pro and currently evaluating
> an X-Talk front end called Revolution for the GUI development and have
> only some general experience with SQL.
>
> Thanks in advance
>
> John Tregea
>
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