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Dec
2
comment create spatial data on the fly for a timeline application
PostGIS can ...
Dec
2
comment finding the outermost border of a set of geomertries (circles)
St_union is what you want. It removes the interior borders. Then checking the distances to the vertexes is not enough since the correct answer might be on an edge between. St_closestpoint will check both vertex points and edges
Dec
2
revised finding the outermost border of a set of geomertries (circles)
added 8 characters in body
Dec
2
comment finding the outermost border of a set of geomertries (circles)
Right you are,thanks :-)
Dec
2
answered finding the outermost border of a set of geomertries (circles)
Nov
30
comment PostGIS doesn't use index for spatial query
You don't use any function that can use the index. Use st_dwithin instead. Then the fuction will first do an index scan.
Nov
19
answered Calculate nearest feature with a barrier
Nov
17
answered Create a point on a line after a specific distance from startpoint
Nov
17
comment Hardware requirements for one instance Geoserver/PostGIS
Great, then I understand. GeoServer and Java is the bottleneck. But as you say it shouldn't be any problem.
Nov
16
comment Hardware requirements for one instance Geoserver/PostGIS
@user30184 Well, if you cache the output so the server only serves static data I gyess 1 GB will give quite decent performance. And to render and cache 20 mb of data in all zoom levels shouldn't be that heavy, should it? But maybe geoserver is demanding, that I don't know so well.
Nov
16
answered Hardware requirements for one instance Geoserver/PostGIS
Nov
11
answered SQL filter to show one layer only if another layer is missing
Oct
28
comment Spatial search performance on a collection of Points in a PostGis database
about "very slow" I have to ask if you really have a functional spatial index. do explain tell you that you have an index scan? and is "very slow" compared to something else or just takes to long to run your query? the slow part of st_dwithin is the recheck where all results from the index scan is checked by real distance calculations. if you just expand bboxes and use the && operator it will be very fast. Look at the sql-definition of st_dwithin how it is done. there is a special trick to keep the index working by expanding one of the two comparing points and then the other.
Oct
28
comment Spatial search performance on a collection of Points in a PostGis database
Well, It can. It could be just that the box have all corners in the point. In PostGIS bboxes is represented with Int32 coordinates and the point with Int64 coordinates. So the box actually has a small area. it doesn't matter if the index gives a few false positive intersections since the result is rechecked.
Oct
27
answered Spatial search performance on a collection of Points in a PostGis database
Oct
18
revised Postgis: Point-in-polygon check + feature attributes inheritance
fix formatting that was messed up when writing from phone
Oct
18
revised Postgis: Point-in-polygon check + feature attributes inheritance
added 18 characters in body
Oct
18
answered Postgis: Point-in-polygon check + feature attributes inheritance
Oct
16
awarded  Nice Answer
Oct
14
comment ST spatial queries to select multi-level location
Your query will not work because the query compares all rows to all rows which means that when the point intersect 1 point it also disjoint at least most of the polygons in table 2. So you need to work with a subquery in some way. There are many options.