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Questions tagged [st]

The tag has no usage guidance.

1
vote
1answer
180 views

How to use st_buffer?

I would like to calculate a buffer of 5km around country polygons. However, I somehow always get a warning and an error. Here is a reproducible example code. library(sp) library(sf) library(tmap) ...
-1
votes
2answers
243 views

Problem with the ST_Area in PostGIS [duplicate]

I have a question with a query in PostGIS. I try to calculate the area from a polygon. It actually works but the area-result is not correct. My Query is: SELECT name, ST_Area(way)/10000 AS hectares ...
1
vote
1answer
258 views

How is ST_Azimuth (in PostGIS) calculated?

What algorithms are internally calculated in PostGIS? Can you explain it with simple code? (I want to know the standard of true north.)
1
vote
1answer
49 views

sfcgal ST_Volume Issue

ST_Volume works with shape data pasted into the query in this form: SELECT (abs(ST_Volume(design)) - abs(ST_Volume(ST_3DIntersection(design,scan)))) FROM (SELECT (ST_MakeSolid('...
2
votes
0answers
79 views

Odd output for PostGIS st_snap

I'm trying to snap a line theme to a point theme using PostGIS with a filter so they only snap to records with the same reference number. The query I'm using is as follows (this is a sample of the ...
1
vote
1answer
479 views

ST_AsRaster for polygon

Having a hard time to get a raster from a polygon ST_AsRaster(ST_Buffer(ST_GeomFromText('POLYGON((-30 40, -20 30, -25 20, -23 10, -30 40))', 4326), 50),ARRAY['8BUI'],ARRAY[118]); This line is giving ...
1
vote
1answer
318 views

ST_Transform error

I am getting an error from ST_Tranform while using ST_Intersection: No function matches the given name and argument types. You might need to add explicit type casts. select ST_Intersection(...
1
vote
1answer
519 views

Finding all polygons inside of a polygon

How to find all the polygons inside of a polygon? I tried ST_Intersects and ST_Contains but they are booleans variables. I have a list of polygons in WKT format, so I am trying to pull all the ...
4
votes
1answer
52 views

Are ESRI spatial views regenerated whenever they are queried?

If a spatial view contains data "joined" from multiple tables, will all the tables be queried whenever a query is executed against the spatial view? We have some spatial views and whenever we run a ...
1
vote
2answers
162 views

Updating table setting a CASE with ST_Intersection

I add a new geometry column to the "mad" table so I could update it with the polygons from an Intersection with the polygons of the table "clip". Since my database is huge an it was taking a lot of ...