Linked Questions

7
votes
0answers
336 views

Solutions for fast operations on large GIS datasets [duplicate]

Possible Duplicate: Acquiring ArcGIS-like speed in Postgis I have been using PostGIS 2.0 for all of my GIS operations. PostGIS is an excellent GIS database, but no matter how I format my queries ...
8
votes
2answers
1k views

PostGIS Union Between Two Tables, Preserving Attributes

I'm trying to union US State level upper- and lower-level government boundaries in such a way that generates one PostGIS table with both the upper and lower level names for each shape. In my example ...
7
votes
3answers
402 views

What would be 'normal' processing time for a large postgis query

I have two datasets which I want to spatially join (with an intersect). The first dataset consists of 9 million addresses. The second dataset consists of 12.000 neighbourhoods. I want the add the ...
3
votes
2answers
412 views

Separating Overlapping DMAs by State using PostGIS?

I have two shapefiles. One is the DMA and another of states I know that some DMAs, such as Chicago will overlap between multiple states, for instance the Denver DMA overlaps states outside of CO and ...
3
votes
1answer
927 views

Speeding up intersect query in PostGIS?

I would like to count the number of points that intersect with a list of polygons. The polygons are very complex (county/state boundaries). I'm using this query: SELECT gid, county_name, (...
2
votes
3answers
696 views

How to get a bbox selection of huge shapefile as GeoJSON?

I have a 4.29 GB Shapefile from which I want to extract features as GeoJSON, defined by a bounding box. This should be as fast as possible, because I want to use it in a web application. My first ...
0
votes
2answers
461 views

Extracting data from four intersecting polygon layers in PostGIS?

I've been using the following code in PostgreSQL/PostGIS for the last year, as needed, which is about once a quarter. It works OK, it's just that it takes days to run. With over 25,000 parcels making ...
0
votes
1answer
247 views

What is the PostGIS equivalent of ArcGIS “Intersect” tool?

I am looking for the PostGIS ST_function that will give me the same results as running the ArcGIS Analyis-> Overlays-> Intersect tool on two polygons.
3
votes
1answer
159 views

QGIS point sample tool faster than in PostGIS - how to improve query?

My points table has 246,338 features and the polygon table has 43,957 features. I am relating the values of one attribute from the polygons to update a column in the points table. This question is ...
2
votes
0answers
167 views

Is PostGIS faster than Shapely [closed]

I've recently tried using Shapely to dissolve and intersect large sets of 100'000+ geometries, some of them quite complex. This would take me at least one hour, at which point I would usually shut the ...
1
vote
0answers
115 views

Quickest Way to Calculate Land Area by Grid Cell in PostGIS

I have a grid vector table that covers the entire world and want to calculate the land area within each grid cell using another table that contains a single polygon for all continents. I tried the ...
1
vote
0answers
38 views

Optimize a query with st_intersect()

I have three tables containing increasingly-complex geometry. I'm clipping Tables 2 and 3 to the first, least-complex table (with 700 multipolygons). The other two tables contain spatial attributes I'...