It is explained on the same web page you're referring to:
https://postgis.net/docs/ST_DWithin.html
For geometry: the distance unit of the geometries's srid (Coordinate
reference system) . The line and point geometry must have the same srid
for geography: meters.
Den 15-05-2020 kl. 12:50 skrev Shaozhong SHI:
Hi, Nicolas,
Thanks.
That is very interesting. I will test it.
I could not find information on how distance is defined. 0.01 stands
on what unit?
https://postgis.net/docs/ST_DWithin.html
Regards,
Shao
On Fri, 15 May 2020 at 11:32, Nicolas Ribot <[email protected]
<mailto:[email protected]>> wrote:
Hi,
You can test for proximity between start and end points
Create spatial indexes on st_startpoint(geom) and
st_endpoint(geom) on your line features table (also index starting
and ending points column in table one)
select t.id <http://t.id>, r.id <http://r.id>, r.geom
from start_end_table t join roads r on st_dwithin(t.startpoint,
st_startpoint(r.geom), 0.01) and st_dwithin(t.endpoint,
st_endpoint(r.geom), 0.01)
Adjust the 0.01 distance according to your data and their precision.
Nicolas
On Fri, 15 May 2020 at 11:42, Shaozhong SHI
<[email protected] <mailto:[email protected]>> wrote:
Given 2 tables. One has the starting and ending points of
roads, and the other has line features. How best to do
spatial linking or selection of road features?
Can anyone enlighten me?
Regards,
Shao
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Med venlig hilsen / Kind regards
Bo Victor Thomsen
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