There is polygon table. I need to find one record from table with some Point (Lat/Long) inside of area.
It's example of coordinates: 149.14668176, -35.32202098
Could you please help me to write select string to find area that contain my Point?
SELECT PostGIS_full_version();
postgis_full_version
POSTGIS="2.5.2 r17328" [EXTENSION] PGSQL="96" GEOS="3.5.1-CAPI-1.9.1 r4246" PROJ="Rel. 4.9.3, 15 August 2016" GDAL="GDAL 2.1.2, released 2016/10/24" LIBXML="2.9.4" LIBJSON="0.12.1" LIBPROTOBUF="1.2.1" RASTER
Something like that:
SELECT id,name FROM area_polygon WHERE ST_Within('149.14668176, -35.32202098', geog);
bounds=# \d bounds.area_polygon;
id | integer | | not null |
geog | geography(Polygon,4283) | | |
name | text | | |
I expected:
id | name
------+--------
1 | Alabama
st_within only supports geometry types, which is why you get the error in the earlier answer, because you have a geography column type.
You can either cast to geometry:
SELECT id,name
FROM area_polygon
WHERE ST_Within(ST_SetSRID(ST_POINT(149.14668176,-35.32202098),4283), geog::geometry);
Or you can use st_dwithin, with distance set to zero:
SELECT id,name
FROM area_polygon
WHERE ST_DWithin(ST_SetSRID(ST_POINT(149.14668176,-35.32202098),4283)::geography, geog,0);
Note that the order of the coordinates must be lon/lat (and not lat/lon) and I am assuming those coordinates are in your SRID 4283. They have to either match the geog SRID or be transformed to it...
See here for a list of which functions support which arguments.
Related
I need to find the closest points to either end of a line using geometry from two separate tables. So far I was able to use the following to find the geometry of the end points:
SELECT "id", ST_StartPoint(dmp.geom) AS upstream,
ST_EndPoint(dmp.geom) AS downstream
FROM sewers.pipes,
LATERAL ST_Dump("geom") AS dmp
;
Using this, I want to use ST_ClosestPoint to find structures that are the closest to the end points of pipes. This is what I've come up with so far:
SELECT ST_ClosestPoint('POINT(SELECT ST_StartPoint(dmp.geom) AS upstream
FROM sewers.pipes,
LATERAL ST_Dump("geom") AS dmp)',
('LINESTRING(SELECT geom from sewers.pipes)'))
However, this gives the following error:
ERROR: parse error - invalid geometry
Line 1: SELECT ST_ClosestPoint('POINT(SELECT ST_STartPoint(dmp.geom)...
HINT: "POINT(SE" <-- parse error at position 8 within geometry
SQL state: XX000
Character: 24
I have provided some sample data below.
sewers.pipes <-- these are the lines
| id | geom |
| -------- | -------------- |
| 822 | 0105000020950B00000100000001020000000200000046243EC3282608418D28242D6C1B3D4128531BE88A2608418284B3EF561B3D41 |
| 6660 | 0105000020950B0000010000000102000000020000004ABF2CBC86B108413B93650696323D413C487924CCB10841925D490495323D41 |
sewers.structures <-- these are points
| id | geom |
| -------- | -------------- |
| 2014 | 0104000020950B00000100000001010000001026FA48113B07410D6A8412CF1D3D41 |
| 22979 | 0104000020950B0000010000000101000000BA1BF246E6DD0741D064CB58C2E43C41 |
I know that there may be an error that comes from selecting multiple data points, eg. more than one row returned by a subquery used as an expression, so that may be an issue as well. Any help would be greatly appreciated.
Try with distinct LATERALs for upstream and downstream:
SELECT p.id,
(dump_line).geom,
ST_EndPoint((dump_line).geom) AS downstream,
geom_closest_downstream,
ST_StartPoint((dump_line).geom) AS upstream,
geom_closest_upstream
FROM sewers.pipes p,
LATERAL ST_Dump(p.geom) dump_line,
LATERAL (SELECT s.geom
FROM sewers.structures s
ORDER BY ST_EndPoint((dump_line).geom)<->s.geom
LIMIT 1) j (geom_closest_downstream),
LATERAL (SELECT s.geom
FROM sewers.structures s
ORDER BY ST_StartPoint((dump_line).geom)<->s.geom
LIMIT 1) i (geom_closest_upstream);
To access the geometries from ST_Dump you have to wrap its output with parenthesis, e.g. (ST_Dump(multiline)).geom
The operator <-> at the ORDER BY clause corresponds to distance. So, using it combined with a LIMIT 1 you get only the closest distance.
Demo: db<>fiddle
Given a list of points and a list of polygons. How do you return a list of points (subset of original list of points) that is in any of the polygons on the list
I've removed other columns in the sample tables to simplify things
Points Table:
| Longitude| Latitude |
|----------|-----------|
| 7.07491 | 51.28725 |
| 3.674765 | 51.40205 |
| 6.049105 | 51.86624 |
LocationPolygons Table:
| LineString |
|----------------------|
| CURVEPOLYGON (COMPOUNDCURVE (CIRCULARSTRING (-122.20 47.45, -122.81 47.0, -122.942505 46.687131 ... |
| MULTIPOLYGON (((-110.3086 24.2154, -110.30842 24.2185966, -110.3127...
If I had row from the LocationPolygons table I could do something like
DECLARE #homeLocation geography;
SET #homeLocation = (select top 1 GEOGRAPHY::STGeomFromText(LineString, 4326)
FROM LocationPolygon where LocationPolygonId = '123abc')
select Id, Longitude, Latitude, #homeLocation.STContains(geography::Point(Latitude, Longitude, 4326))
as IsInLocation from Points PointId in (1, 2, 3,)
which would return what I want in a format like the below. However this is only true for just one location on the list
| Id | Longitude| Latitude | IsInLocation |
|----|----------|-----------|--------------|
| 1 | 7.07491 | 51.28725 | 0 |
| 2 | 3.674765 | 51.40205 | 1 |
| 3 | 6.049105 | 51.86624 | 0 |
How do I handle the scenario with multiple rows of the LocationPolygon table?
I'd like to know
if any of the points are in any of the locationPolygons?
what specific location polygon they are in? or if they are in more than one polygon.
Question 2 is more of an extra. Can someone help?
Update #1
In response to #Ben-Thul answer.
Unfortunately I don't have access/permission to make changes to the original tables, I can request access but not certain it'll be given. So not certain I'll be able to add the columns or create the index. Although I can create temp tables in a stored proc, I might be able to use test your solution that way
I stumbled on an answer like the below, but slightly worried about performance implications of using a cross join.
WITH cte AS (
select *, (GEOGRAPHY::STGeomFromText(LineString, 4326)).STContains(geography::Point(Latitude, Longitude, 4326)) as IsInALocation from
(
select Longitude, Latitude from Points nolock
) a cross join (
select LineString FROM LocationPolygons nolock
) b
)
select * from cte where IsInALocation = 1
Obviously, it's better to look at a query plan but is the solution I stumbled upon essentially the same as yours? Are there any potential issues that I missed. Apologies for this but my sql isn't very good.
Question 1 shouldn't be too bad. First, some set up:
alter table dbo.Points add Point as (GEOGRAPHY::Point(Latitude, Longitude, 4326));
create spatial index IX_Point on dbo.Points (Point) with (online = on);
alter table dbo.LocationPolygon add Polygon as (GEOGRAPHY::STGeomFromText(LineString, 4326));
create spatial index IX_Polygon on dbo.LocationPolygon (Polygon) with (online = on);
This will create a computed column on each of your tables that is of type geography that has a spatial index on it.
From there, you should be able to do something like this:
select pt.ID,
pt.Longitude,
pt.Latitude,
coalesce(pg.IsInLocation, 0) as IsInLocation
from Points as pt
outer apply (
select top(1) 1 as IsInLocation
from dbo.LocationPolygon as pg
where pg.Polygon.STContains(p.Point) = 1
) as pg;
Here, you're selecting every row from the Points table and using outer apply to see if any polygons contain that point. If one does (it doesn't matter which one), that query will return a 1 in the result set and bubble that back up to the driving select.
To extend this to Question 2, you can remove the top() from the outer apply and have it return either the IDs from the Polygon table or whatever you want. Note though that it'll return one row per polygon that contains the point, potentially changing the cardinality of your result set!
I have the following table:
postgres=# \d so_rum;
Table "public.so_rum"
Column | Type | Collation | Nullable | Default
-----------+-------------------------+-----------+----------+---------
id | integer | | |
title | character varying(1000) | | |
posts | text | | |
body | tsvector | | |
parent_id | integer | | |
Indexes:
"so_rum_body_idx" rum (body)
I wanted to do phrase search query, so I came up with the below query, for example:
select id from so_rum
where body ## phraseto_tsquery('english','Is it possible to toggle the visibility');
This gives me the results, which only match's the entire text. However, there are documents, where the distance between lexmes are more and the above query doesn't gives me back those data. For example: 'it is something possible to do toggle between the. . . visibility' doesn't get returned. I know I can get it returned with <2> (for example) distance operator by giving in the to_tsquery, manually.
But I wanted to understand, how to do this in my sql statement itself, so that I get the results first with distance of 1 and then 2 and so on (may be till 6-7). Finally append results with the actual count of the search words like the following query:
select count(id) from so_rum
where body ## to_tsquery('english','string & string . . . ')
Is it possible to do in a single query with good performance?
I don't see a canned solution to this. It sounds like you need to use plainto_tsquery to get all the results with all the lexemes, and then implement your own custom ranking function to rank them by distance between the lexemes, and maybe filter out ones with the wrong order.
I ran the following commands in posgresql 9.6:
./bin/createdb testSpatial
./bin/psql -d testSpatial -c "CREATE EXTENSION postgis;"
create table test(name character varying(250), lat_long character varying(90250), the_geom geometry);
\copy test(name,lat_long) FROM 'test.csv' DELIMITERS E'\t' CSV HEADER;
CREATE INDEX spatial_gist_index ON test USING gist (the_geom );
UPDATE test SET the_geom = ST_GeomFromText(lat_long,4326);
On running: select * from test; I get the following output:
name | lat_long
|
the_geom
------+-----------------------------------------------------------------------------------------------------------------------------------------
---------------------------------------------------+--------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------
A | POLYGON((-0.061225 -128.427791,-0.059107 -128.428264,-0.056311 -128.428911,-0.054208 -128.426510,-0.055431 -128.426324,-0.057363 -128.42
6124,-0.059315 -128.425843,-0.061225 -128.427791)) | 0103000020E61000000100000008000000D42B6519E258AFBFBE50C076B00D60C07DE9EDCF4543AEBFBC41B456B
40D60C08063CF9ECBD4ACBFA1BC8FA3B90D60C07BF65CA626C1ABBF58AD4CF8A50D60C0BF805EB87361ACBFFFAF3A72A40D60C0B83A00E2AE5EADBF4D81CCCEA20D60C01F1153228
95EAEBF60C77F81A00D60C0D42B6519E258AFBFBE50C076B00D60C0
B | POINT(1.978165 -128.639779)
| 0101000020E61000002D78D15790A6FF3F5D35CF11791460C0
(2 rows)
After this I ran a query: To find all "name" which are within 5 meters of each other. For doing so, I wrote the following command.
testSpatial=# select s1.name, s2.name from test s1, test s2 where ST_DWithin(s1.the_geom, s2.the_geom, 5);
name | name
------+------
A | A
A | B
B | A
B | B
(4 rows)
To my surprise I am getting incorrect output as "A" and "B" are 227.301 km away from each other (as calculated using haversine distance here: http://andrew.hedges.name/experiments/haversine/). Can someone please help me understand as to where am I going wrong.
You have defined your geometry as follows
the_geom geometry
ie, it's not geography. But the ST_DWithin docs say
For Geometries: The distance is specified in units defined by the
spatial reference system of the geometries. For this function to make
sense, the source geometries must both be of the same coordinate
projection, having the same SRID.
For geography units are in meters and measurement is defaulted to
use_spheroid=true, for faster check, use_spheroid=false to measure
along sphere.
So you are actually searching for places that are within 5 degrees of each other. A degree is roughly equal to 111km so you are looking for places that are about 550 km from each other rather than 5 meters.
Additionally, it doesn't make much sense to store strings like POINT(1.978165 -128.639779) in your table. It's completely redundant. It's information that can be generated quite easily from the geography column.
The following statement always returns the result from st_area(st_buffer(polygon,100)).
select st_Area(polygon) as area,
case when area>100000 then st_area(st_buffer(polygon,500))
else st_area(st_buffer(polygon,100))
end from polygons limit 10;
area | st_area
------------------+------------------
383287.287473659 | 723738.615102036
47642.5395246768 | 192575.823383778
45546.753026985 | 174122.420564731
435204.455923533 | 725419.735987631
839954.564052786 | 1268251.88626391
315213.27742828 | 630424.785088617
966620.061916605 | 1447647.57269461
38446.6010009923 | 151584.647252579
82576.1182937309 | 238095.988431594
321682.125463567 | 695462.262796463
(10 rows)
st_area should have been the result of st_buffer(polygon,500) when area>100000 as shown below:
area | st_area
------------------+------------------
383287.287473659 | 2702203.34758147
47642.5395246768 | 192575.823383778
45546.753026985 | 174122.420564731
435204.455923533 | 2507469.89929028
839954.564052786 | 3568866.96452707
315213.27742828 | 2453576.33477712
966620.061916605 | 3953365.12876066
38446.6010009923 | 151584.647252579
82576.1182937309 | 238095.988431594
321682.125463567 | 2628693.69179652
(10 rows)
Can someone explain?
It doesn't become completely clear from the question (yet), but my educated guess is you want this:
SELECT st_Area(polygon) AS area -- or pick some other name!
, CASE WHEN st_Area(polygon) > 100000
THEN st_area(st_buffer(polygon,500))
ELSE st_area(st_buffer(polygon,100)) END AS st_area
FROM polygons
LIMIT 10;
You cannot reference the column alias (name of the output column) in another item of the same SELECT list. You can only reference input column names. So you have to repeat the expression or use a subquery:
SELECT area
, CASE WHEN area > 100000
THEN st_area(st_buffer(polygon,500))
ELSE st_area(st_buffer(polygon,100)) END AS st_area
FROM (SELECT st_Area(polygon) AS area, polygon FROM polygons LIMIT 10) sub;
Normally you should get a syntax error immediately. Obviously, there is another column named area in your base table. Hence the confusion. Additional wisdom to take away from this:
It's better to use a name different from any input column when attaching an alias to an output column.
Always include table definitions in questions. Clarifies a lot.