PostGIS is an extension for the PostgreSQL object-relational database that adds support for geographic objects.

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117 views

How to compute the smallest network that connects all points using PostGIS?

I have a set of postgis scripts which generates two tables - one of a set of points and the second a set of roads which surround them. All data is in the same projection and both outputs are stored in ...
5
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31 views

How to extract sublinestring from a linestring with overlapping segments

Problem statement: Given a bus route (defined as a linestring ln.the_geom), and a set of bus stop locations (pt1.the_geom,pt2.the_geom,...ptn.the_geom), divide the bus route into segments between bus ...
5
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721 views

How to create a routable road network from Ordnance Survey data?

I've been following the "Beginners Guide to pgRouting" in an attempt to create an in-house application that provides drive-time isochrones. I have a server, postgreSQL and PostGIS and pgRouting - no ...
4
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45 views

Focal Statistics for Special Neighborhood

I'm looking to calculate focal statistics for each cell of a raster, within a neighborhood of a specified criteria. Background - I have three binary rasters, each representing a single vegetation ...
4
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59 views

Compute visibility graph on sphere

I have a PostGIS table with some polygons (stored using the geography data type). They represent regions on a spherical earth. For each pair of vertices chosen from among all the polygons, I want to ...
4
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119 views

Find and destroy duplicate OSM multipolygon/polygons in TileMill/PostGIS

In OpenStreetMap there are sometimes multipolygons where attributes are present on both the polygon and the multipolygon relation, such as the Grampians National Park: ...
4
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212 views

How to create a topologically correct dataset in PostGIS (with GRASS)?

I have shapefiles which I have loaded in postgis and now i am trying to use geometric function in postgis like ST_intersect and they fail because the data is not topological correct. I have tried to ...
4
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120 views

Joining layers with respective elements with PostGIS Topology

Recently I have started using PostGIS topology extension, but I have some difficulties in understanding how the structure works: One of the key points is the use of "layer"s: as of what I understand, ...
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315 views

Geoserver WMS-T backend problems

I've been trying to set up a few timed WMS layers in GeoServer. They're simple enough, of the form ID(PRIMARY KEY) REGION DATE VALUE so for every region and date you have some value, e.g. the ...
3
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33 views

Postgis database query optimisation

I have a set of rasters in DTED format which I load into postgis database using raster2pgsql command line tool. Each of rasters is simply stored in a row and described by rid and a value of raster ...
3
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45 views

Create a Shape file from Sql dump file

I am trying to map data by querying a table called xyz. I need to show the the_geom data on the map. I have below query in my mapserver .map file: DATA "the_geom from xyz using unique id using ...
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57 views

Intersection of a vector linestring and underlying DEM

Following is an screen-shot where ASTER DEM raster layer has been overlaid by a road linestring vector layer. I want to extract those DEM pixels which are lying exactly beneath the linestrings. I want ...
3
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57 views

Problem with performance when loading PostGIS layer using pyQGIS

I'm having a question on loading a PostGIS layer into the project from my QGIS plugin. The code is like this: uri1 = qgis.core.QgsDataSourceURI() uri1.setConnection(str(host), str(port), ...
3
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75 views

How do I simplify the straight sections of (multi)Linestring in PostGres/PostGis leaving the curved sections untouched

I have (multi)linestrings containing upwards of 5000 points and I want to perform two simplifications possibly using Ramer Douglas Peucker or alternative methods in PostGis The (multi)linestrings ...
3
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173 views

Postgis - extrude a polygon

I want to extrude a polygon shape in postgis to create a pseudo 3D effect. To this end I have written a crude function to achieve it. This is very much test code and it creates a new Y vertice for ...
3
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327 views

Hibernate Spatial - 'Invalid endian flag value encountered' Exception

I'm trying to run a simple query in Hibernate Spatial 4.0 on PostgreSQL 9.3. I have a number of objects in a table with latitude/longitude values, and I'm trying to query objects that fall within a ...
3
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70 views

Why are date vaules displaying a trailing 'Z' when layers are published with Geoserver and a PostGIS data store?

I have published various layers using Geoserver 2.2.x with a PostGIS 2.0.1 (PostgreSQL 9.1.x) data store. Fields that only have date values and not time/timestamp related values are stored as date. ...
3
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78 views

Add attribute table to a raster in postGIS

I would like to add attributes to a raster stored in a postgis database. I use the following command to insert the raster in the database: raster2pgsql -s 4236 -I -C -M ...
3
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250 views

Finding poi using st_dwithin in postgis

I am not familiar with gis or writing sql, so my understanding in this field is lacking. I have a hundreds of lat/lng geographic coordinates stored in a single table called Places like this: ID | ...
3
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224 views

Find points that fall within a radius using Hibernate Spatial

I am using hibernate spatial and postgis and i want to find the points that fall within a certain radius. Using this SQL: SELECT name FROM institution WHERE ...
3
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334 views

Extracting x,y,z values from a postgis linestring to python using ogr

I am trying to load a postgis linestring into python (using ST_DumpPoints) and extracting x,y,z coordinates, which is working but extremely slow..and if i mean slow, i really mean it (yes, it takes ...
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185 views

building larger polygons from smaller ones *without* a common id in PostGIS

I am looking for a means, using PostGIS, of reconstituting a set of polygons from tens of thousands of smaller polygon 'pieces'. This is a simplified example, with the pieces shaded: Unfortunately ...
3
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279 views

How to import PostGIS layer with geography type to QGIS?

I tried to import in QGIS a layer from a PostgreSQL table with a geography type column created through the extension PostGIS. I noticed that QGIS doesn't seem to like the geography column... Here ...
3
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210 views

Creating Ellipse in WGS84, but with metric parameters

I have the function --Ellipse(x,y,rx,ry,rotation,#of segments in 1/4 of ellipse) SELECT ST_Translate( ST_Rotate( ST_Scale( ST_Buffer(ST_Point(0,0), 0.5, $6), $3, $4), $5), $1, $2) I have points in ...
3
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235 views

Is there a way to start the route on pgrouting from a coordinate that is not a node?

After execute all steps from this pgRouting tutorial, now I have a map that creates and displays routes, but as the routing methods rely on parameters representing vertex Ids that was created using ...
3
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129 views

Create a consistent topology using pgrouting

I'm developing an application that needs routing information for certain cities. First, I downloaded a openstreetmap datafile (*.osm) and then I imported it into a postgreSQL database using ...
3
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269 views

Shortest distance from pgrouting with cost not being length: optimal solution

I'm using pgrouting shortest_path_astar with a complicated cost function. It gives back the edges, vertices and costs. I would like to get the total distance of this shortest path (i.e., the sum of ...
3
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397 views

How to save table from PostgreSQL to MapInfo File?

I have two tables: 1 with geometry in WGS 2 with geometry in Local System I tried this: ogr2ogr -f "MapInfo File" output2.tab PG:"host=localhost user=postgres password=123456 dbname=postgis" -sql ...
3
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472 views

How can I properly add PostGIS data into MapGuide Maestro?

I am having trouble connecting a PostGIS database to MapGuide Maestro. Actually, I have added the PostGIS data into Maestro, but when I click to validate the layer it shows an error message: ...
2
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28 views

How can I export to .shp file with only the geom column with PostGis?

I have multi-linestring in .shp files and I split the lines with postgis, but that result is only geom column. It does not works with shape file exporter error: incompatible mixed geometry types ...
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40 views

How to get user and password of a PostGIS layer

I wonder if it is possible to get the user and password for a PostGIS database if they are stored in the PostGis connection information. I get the connection information at the moment from the ...
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38 views

How to plot heatmap/locations in Geoserver & Openlayers map from the Lat/Lon data of PostGIS table?

I am using Geoserver, Openlayers, PostGIS for Geospatial web implemenation. I have an Indian map shape files for States, Districts, Talukas. I am able to generate a map with states, districts, ...
2
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26 views

OpenGeo: GeoExplorer cannot upload shapefiles into PostGIS

I have installed OpenGeo 4.1 on Ubuntu Linux 12.04 following the official instructions. I then followed the tutorial Load your data with GeoExplorer. I was able to zip and upload a few shapefiles. ...
2
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39 views

Rebuilding a Polygon from the points within it, in PostGIS

This question is an update on the problem formulated here. I wanted to redefine the border of a set of polygons, in order to "smooth it". My first approach (described in the former question) was to ...
2
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15 views

ArcGIS dissolve analysis output issues in geoserver wfs/ PostGIS

I have an ArcGIS dissolve analysis output (parcel data) that needs to be loaded on PostGIS and published as a wfs from geoserver. The issue is that the ArcGIS dissolve output shapefile, although can ...
2
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37 views

QGIS There isn't entry in geometry_columns!

In PostgreSQL v9.3 with PostGIS v2.1 extensions I created a view from two tables (sites & visits). The site table contained a point geometry column (the_geom), which was included in the created ...
2
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45 views

Point sampling along a pole-wrapping coastline with PostGIS

I am working on a task that requires me to get sample points every 1000KM along coastlines, and have run into a problem with Antarctica. From what I can tell, it seems to be an issue with the use of ...
2
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62 views

N Nearest Neighbours efficiently PostGIS/Python

The data is worldwide about a million points, lat/lons, with an id and an importance value (0.0 to 1.0), and it's limited to being on land. Ideally I need to cluster all 1 million points into 100,000 ...
2
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65 views

Is it possible to create an ellipse around a line in 3D space?

In Postgis 2.1.1, I have a line in 3 dimensional space connecting two antenna points on the earth's surface. Is it possible to create an ellipse around that line? I have a formula to compute the ...
2
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42 views

PostGIS “Overlay” Style Union, not “Dissolve” Style

I'm trying to use PostGIS to do a 'union' of polygons. When I Googled "PostGIS Union", I found the ST_Union function, which performs what I would call a 'dissolve,' not a Union. What I actually want ...
2
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36 views

Determine PostGIS geography polygon orientation

How can you determine the orientation of a PostGIS geography polygon? I'm looking/hoping for a function that would tell me which side is the interior (left or right) as you traverse the vertices of ...
2
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0answers
35 views

Use of postgis with hibernate

We have an existing postgis database. Our application is developed in Java, but queries database through a jni dll, which appears to be not very effective for our purpose. I've managed to migrate to ...
2
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0answers
78 views

Rotation by attribute in Geoserver SLD style

I have a table with field calculated by function: NEW."rotationAngle" := degrees( ST_Azimuth( ST_StartPoint(NEW.the_geom) ...
2
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0answers
42 views

How to get the nearest points from pgrouting linestring result?

I'm trying to get the points or landmarks near from the result of pgrouting linestring( the shortest path ). I'm using OSM map entities and working with planet_osm_point. Here's my codes. SELECT ...
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60 views

Weird-looking France after OSM import with osm2pgsql

After importing france-latest.osm from Geofabrik, using osm2pgsql, it seems that the polygon attributed to Metropolitan France (osm_id = 1403916) is a bit odd: I'm far to be a geography expert, but ...
2
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31 views

GeoServer ImageMosaic PostGIS index update

I use GeoServer where I created an ImageMosaic storage following this manual. When I create new datastore, all *.tif files are indexed into DB (PostgreSQL with PostGIS). How can I create new index in ...
2
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53 views

How to export postgis points as blocks in dxf with ogr2ogr

I'm trying to export postgis points as blocks to DXF format. I have a simple table in postgis with columns: CREATE TABLE pod_com_azimuth ( ogc_fid integer, rotation double precision, pointtype ...
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24 views

PostGIS query with input from point layer

I have a table of rivers in PostGIS, each river linking to its outflow. I also have a QGIS layer of some selected sources, and would like to select the entire river downwards from each source (i.e. ...
2
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120 views

qgis-2.2.0 database tab missing

I have recently installed QGIS-2.2.0 but the Database tab in the top-menu bar is missing. It looks the main reason is missing libgdal1h library. But when I am installing it, it's removing ...
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136 views

TileMill Exports Failing

I'm having trouble exporting my map in TileMill (v0.10.1). I'm using OSM Bright with a PostGIS database connection to import OpenStreetMap data. When exporting an SVG or PDF through the user interface ...