A spatial data infrastructure (SDI) is a data infrastructure implementing a framework of geographic data, metadata, users and tools that are interactively connected in order to use spatial data in an efficient and flexible way.
7
votes
3answers
457 views
Can spatial index help a “range - order by - limit” query
Asking this question, specifically for Postgres, as it has good supoort for R-tree/spatial indexes.
We have the following table with a tree structure (Nested Set model) of words and their ...
5
votes
2answers
196 views
Less restrictive query return less result due to simple removing one additional constraint
Look at this query
SELECT DISTINCT
TB.ID,
TB.Latitude,
TB.Longitude,
111151.29341326*SQRT(pow(-6.185-TB.Latitude,2)+pow(106.773-TB.Longitude,2)*0.98839228980165) AS Distance
FROM
...
6
votes
2answers
786 views
How do Application Like Yelp Retrieve distance information from data base efficiently
For example, say I have a table:
Business(BusinessID, Lattitude, Longitude)
All are indexed of course. Also there are 1 million records
Say I want to find businesses closest to 106,5, for example, ...
0
votes
2answers
208 views
migrate SQL Server geography data to PostGIS geometry data
I'm trying to use SSIS to transfer point data from a Geography column in SQL Server 2008 R2 to a geometry column in a Greenplum (Postgres 8.2.15) database with PostGIS. I know there's a way to do the ...
