I use a custom equal area projection for some large oceanic regions I work in, but depending on the extent of your linestrings, it is likely that the UTM projection for your part of the globe will give a reasonable result, if you are not too near the poles.
You may even find native lat/long gives an acceptabvle result, it all depends on how much precision you need for your purposes. Given around 110,000m/degree, if you just want a small buffer around the linestring, and whether it is 5m or 15m doesn't matter, you could try buffering with your lat/long data & a distance of 0.0001 degrees, which should be around 10m, depending on your latitude. --- On Sat, 3/3/12, Ed Linde <edoli...@gmail.com> wrote: From: Ed Linde <edoli...@gmail.com> Subject: Re: [postgis-users] Forming a BAND around a linestring To: pcr...@pcreso.com Cc: "PostGIS Users Discussion" <postgis-users@postgis.refractions.net> Date: Saturday, March 3, 2012, 7:18 AM Thanks for the tip! Do you recommend a "suitable projection" for the buffer operation that will not produce distorted buffers? On Fri, Mar 2, 2012 at 7:15 PM, <pcr...@pcreso.com> wrote: ST_Buffer(<linestring>, distance) http://www.postgis.org/docs/ST_Buffer.html Note that if your data is lat/long (such as EPSG:4326) with units in degrees, then you will get somewhat distorted buffer distances, and a better result by transforming your linestring to a more suitable projection for the buffer operation, then transform it back. eg: ST_Transform(ST_Buffer(ST_Transform(<linestring>, SRID), distance),4326) HTH, Brent Wood --- On Fri, 3/2/12, Ed Linde <edoli...@gmail.com> wrote: From: Ed Linde <edoli...@gmail.com> Subject: [postgis-users] Forming a BAND around a linestring To: "PostGIS Users Discussion" <postgis-users@postgis.refractions.net> Date: Friday, March 2, 2012, 11:17 PM Hi All, I have a set of points with (x,y) co-ordinates that belong to a single object ex: a segment in a road network.If we made a LINESTRING that connected these points (x,y), then I would like to have a BAND or RANGE around the linestring of say 10 meters wide that would probably make it look more like a polygon or some area. How can I achieve this in postgis 2.0? Do I need to use some library like GDAL in order to achieve this? Cheers,Ed -----Inline Attachment Follows----- _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
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