7,298 reputation
11223
bio website blog.jordogskog.no
location Hedmark, Norway
age
visits member for 3 years, 6 months
seen 20 hours ago

Mar
13
comment Select point with highest value within a buffer
This seams to be a work for a spatial database to do with sql.
Mar
12
comment using postgis function in pyqgis
You need a second parameter for the buffer function that tells what buffer you want.
Mar
7
comment spatial database vs spatial datastructure?
Yes, I think PostgreSQL is much faster. That is often the case :-)
Mar
7
comment spatial database vs spatial datastructure?
You don't need to do the bounding box comparassion manually. It is built into ST_Intersets.
Nov
20
comment How can I improve the performance and start-up time of arcgis 10.x?
If you have a bad connection to the license server that can make things very slow. Note that license servers is not needed with open source software :-)
Nov
11
comment ST_Intersection point of two 3D linestrings - how is the Z value calculated?
This will not give the right answer in all cases. example is the linestrings: LINESTRING(2 0 0, 2 6 50) and LINESTRING(0 3 0, 5 3 0)
Nov
5
comment How to get the nearest point on a linestring to a given point?
St_distance between the point and the line will give you the same answer. Why do you think that you have to do it this way?
Oct
29
comment PostGIS ST_Contains Function Error
Upper or lower case in function names doesn't matter in PostgreSQL
Oct
7
comment Shortest distance from point to line (big dataset)
Postgis should do it fast
Jun
20
comment SQL Server 2008 Distance and Performance Problem
If it not is PostGIS beta (2.1) that you have been using it is just raw brutal force calculation in PostGIS which SQL Server ought to be on pair with. I do not know the SQL Server syntax either, but it seems like you cast the geometry to string in the query, why? That can be very expensive if then the distance function auto casts back to geography.
Jun
20
comment SQL Server 2008 Distance and Performance Problem
is it the exactly same data set?
Jun
20
comment ST_DWithin uses Geometry or Geography type
It is not casting to geography that makes it slow. But doing calculations on the sphere instead of just euclidean is far more expensive. But I think PostGIS 2.1 will be a lot faster here. Paul has put in some smart tree structures for making things happen faster. Look at postgis.net at the release notes for postgis 2.1 beta 2 (I think it was released today)
Jun
18
comment Why is sum of st_length() of segments 20% too big?
How can you solve this with an error factor when the error depends on the direction of the line/distance? north<->south distances have no error but west<->east do.
Jun
16
comment Insert into X coordinate separately?
I am still confused about what you really want to do. You use the word update and insert together. That doesn't make sense. If you insert you add a new row (with the same data types as the other rows in the table). If you update you change the value in an existing row.
Jun
13
comment Web service to see postgis polygons
press "Map 1", you can also press the number"2" button to get a quick tour, how to use the site.
Jun
7
comment Looking for fastest solution for Point in Polygon analysis of 200 million points
Well, I don't remember, but I guess it was default since I almost never do anything about that.
May
13
comment javascript WKB to WKT function
Btw, you should not use blobs but arraybuffer.
May
13
comment javascript WKB to WKT function
+1 TopoJSON seems very interesting
Apr
8
comment Storing features in PostGIS and then creating layers using queries
As you say it is a common case, but mostly it is just ignored and the redundant information is accepted. That can cause problems when editing with separate polygons, but is much easier to implement and port between different formats and needs.
Apr
6
comment Storing features in PostGIS and then creating layers using queries
If I understand you right, PostGIS topology might be what you are looking for.