Version 2.0 of PostGIS brought a heavy set of new extensions for the PostgreSQL object-relational database, adding greater support for spatial objects.

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2
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1answer
56 views

Is there a way to use some sort of “instancing” when storing polygons in a spatial database?

I am quite new to GIS database addons, and I am still exploring the possible uses for them. In general the idea of storing objects indexed by their position which enables additional operations is ...
2
votes
1answer
817 views

PostGIS Select Union of Polygons

I have a Postgres 8.4 PostGIS 2.0 enabled database and I've loaded it up with a bunch of shapefiles. I'm trying to get the database to do on-the-fly unions of geometries. Here is the query I'm ...
4
votes
1answer
1k views

Copy a spatial table from one PostGIS database to another PostGIS database

I have two PostGIS databases on two different servers. The first server is PostGIS 2.0 and the second server is PostGIS 1.5. On the PostGIS 2.0 I have a table "lakes" with MULTIPOLYGON geometry ...
6
votes
3answers
2k views

Loading geotiffs into PostGIS using raster2pgsql

I have an issue with loading some Ordnance Survey raster data into PostGIS. I have been using the following raster2pgsql command to load a tif that I have placed in my C:\Program ...
1
vote
2answers
120 views

ST_Length (GEOM, true) for calculating distances in Geographic Reference System

Good afternoon all, I use (1) ST_Length (ST_Transform (geom, 3395)) to get distances in meters from points in Geographic Reference Systems EPSG: 4326. The thing is I found that with (2) ST_Length ...
2
votes
1answer
166 views

GeoDjango: read geometry column in geography field

I have a Django application that needs to work with an existent PostGIS database, apart from its own database. I've configured multidatabase support, created a database router, created models for the ...
2
votes
1answer
94 views

PostGIS ST_SummaryStats

I need some help writing the sql for returning the "MEAN" value from a raster(in postgis db) that intersects a defined(inquery) polygon(in postgis db). The polygon layer is called: ...
0
votes
1answer
50 views

Where and what format GIS data is suitable for me? [closed]

I am a student on computer science.Now , I am on a competition which is to develop a taxi recommendation system for Beijing ,China. I am now looking for the GIS data of Beijing. The key step is , ...
0
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2answers
61 views

Select area which is at least x meters away from other geometries

In my table I have the build-up area from a region as a big number of polygons. urban_area: id | name | geometry(polygon) I was wondering if and how I would be able to find the area within a ...
1
vote
0answers
94 views

St_OffSetCurve with self-crossing lines

I have about 50,000 linestrings in PostGIS. They represent routes along roads. But I want them to be (roughly) pavements (aka sidewalks) instead. So I need to move all the lines 3 metres to the left ...
1
vote
1answer
80 views

Get DISTINCT nearest neighbors with indexed search

I'm using the indexed nearest neighbor search to return the closest points to a given starting location. My points also have attributes like color and shape, stored as strings. I want each query to ...
1
vote
2answers
73 views

Ogr2ogr - shape to postgis - is there a way to use and preserve an existing primary key?

I've been struggling with this for a while, tried a few different ideas inspired by these pages: http://www.gdal.org/ogr2ogr.html http://www.gdal.org/ogr/drv_pg.html ...
8
votes
1answer
327 views

What is the precision of SELECT DISTINCT on PostGIS geometry column?

I wonder what the precision of the SELECT DISTINCT operator is on a PostGIS geometry. On my system, the following query gives me a count of 5, which means that the inserted points are considered equal ...
2
votes
1answer
39 views

Weird behaviour of ST_Project with PostGIS2

somehow I can't understand the results of ST_Project, but maybe this problem is just me being stupid (again): Note: I use geography-type here, but the results are the same for geometry. I use a ...
0
votes
1answer
57 views

Problem with double field type in postgis database

I have connection to PostGIS spatial database through ArcSDE, and all double type numeric fields are cutting numbers after comma. Does anyone know how can I fix this problem?
0
votes
1answer
342 views

How to install pgrouting 2.x on ubuntu 12.04 LTS

I try to install pgrouting 2.0 on ubuntu 12.04 LTS with postgresql 9.2 I have ppa in the system by sudo add-apt-repository ppa:gwibber-daily/ppa answer: `You are about to add the following PPA to ...
6
votes
5answers
2k views

How to split OSM roads into individual segments at intersections?

I want to create a road-network for use with pgRouting using OpenStreetMap data. I loaded a shapefile from GeoFabrik into a Postgres table (with PostGIS enabled). However, one problem I had was that ...
2
votes
2answers
691 views

Importing planet files into Nominatim

After a gruesome night installing PostgreSQL 9.1, PostGIS 2 and Nominatim 2 on CentOS 6.3 using the instructions here, I am finally at the stage of importing a US planet file. Problem: In ...
1
vote
0answers
132 views

identify subgraphs within planet_osm_line table

I want to identify subgraphs within the planet_osm_line table of the osm2pgsql-schema. those subgraphs are classified by certain tags i want to check. My first attempt was to do this recursively with ...
0
votes
1answer
159 views

ImageMosaic-JDBC Error

I'm trying to get postgis raster layers in geoserver-2.3.1, with postgresql-8.4, postgis-2.0 and gt-imagemosaic-jdbc-9.1.jar support. I'm going through the tutorial with a PNG raster that i have. In ...
1
vote
0answers
216 views

Problem Installing pgRouting 2.0; libcgal8 dependency

I've been trying to install PostGIS and pgRouting on an AWS Ubuntu server (first tried 13.10, then reverted to 12.04, both 64bit "small" instance) for several days now but no matter what I do I keep ...
0
votes
1answer
204 views

Coordinate Conversion in PostGIS

I have some problem with the representation of the coordinates. I need to convert the coordinates from "EPSG: 32633" to "EPSG: 4326", and then create geometries in PostGIS. For the conversion (from ...
0
votes
1answer
95 views

PostGIS Transform distance or create a view

I have a postgis table that is updated on a regular basis so it is not practical to cast my geometry column to geography So can I modify the following query to convert a distance say 0.5k into ...
0
votes
1answer
79 views

Installation extension functions to pgRouting

I'm trying to find sql source of functions routing_dd.sql and routing_dd_wrappers.sql I'm working on Windows 7 32bit. The only one link to that wrote by Underdark is empty: Both are available ...
5
votes
0answers
98 views

What PostGIS [topology] provided tools may be used for data quality assurance?

I'm learning about techniques to ensure GIS data quality. Googling around, I've found a few papers about theory and best practices (here and here), and a couple of short presentations about the topic ...
1
vote
1answer
3k views

How can I enable PostGIS Shapefile and DBF Loader 2.0 plugin in PgAdmin III?

I am on Windows and I want to download/enable the plugin "PostGIS Shapefile and DBF Loader 2.0". I installed PostGIS 2.0 using StackBuilder of PostgreSQL installer.
1
vote
1answer
52 views

What is the complexity of neigborhood search in PostGIS?

I have a point with coordinates x and y. I want to know all the points in a square around this point, with side L. For this, in postgresql/PostGIS, I use: SELECT * FROM table_of_points WHERE ...
3
votes
1answer
399 views

osm2pgsql: Import data in custom projection

I have osm-file and I want to import it to the postgresql via osm2pgsql with custom projection EPSG:20022. I look to the help and found out any keys like -E EPSG: but when I try to do with it I get ...
2
votes
1answer
534 views

PostGIS: Calculate the length of just the portion of linestring that intersect with a polygon

I want to calculate the portion of the linestring that lies within the limits of a polygon. Better with an image What is the length of the portion of linestring within Province A? and within ...
4
votes
1answer
217 views

Update PostGIS after updating GDAL?

I am using PostGIS 2.0 and I want to use the raster functionality through mapserver. It seems as if the latest official GDAL release 1.9.1 has an unstable PostGIS raster driver, as pointed out in a ...
7
votes
2answers
2k views

Postgis 2.0 upgrade problem with postgres data [SOLVED]

I have a serious problem: on Wednesday, April 2 OpenSUSE 12.1 is updated, and the package was to update the PostGIS-a version 1.5.3 to 2.0.0. After this operation, Postgres does not display records. ...
0
votes
1answer
243 views

How to calculate x, y, z, m in Postgis

Somebody know how can I calculate the x,y,z,m parameters from a MultiLineStringZM in Postgis? I would like to know x,y,z and m from the points what are made the polyline. When I try calculate it by ...
3
votes
2answers
2k views

What is the unit used in ST_Distance()?

I wonder what the unit is of the float being returned from ST_Distance. In the documentation it says: ...cartesian minimum distance (based on spatial ref) between two geometries in projected ...
0
votes
1answer
25 views

How to join two LinestringM into one without dropping M value?

I have, for example, two Linestrings with M value: LINESTRINGM(1 0 2, 2 0 4, 4 0 7) and LINESTRINGM(4 0 7, 6 0 9, 10 0 10) How can I merge them into one Linestring and preserve the M value? Expected ...
18
votes
1answer
2k views

Comparison of geocoding solutions (such as Gisgraphy & PostGIS 2.0)

As I am sure many of you are aware, PostGIS has finally released Version 2.0 and included within this version they have also built a geocoder (see: http://postgis.net/docs/Extras.html). Although I ...
10
votes
1answer
536 views

How to get the length of a line inside a polygon

How can I get the length (brown marked part) of the "Road 7" inside the red polygon? My start: SELECT ST_Length(way) FROM lines WHERE road = "Road 7" AND ST_Intersects(line, polygon)? With that, ...
7
votes
6answers
2k views

Unable to connect Postgis from QGIS 1.8.0

I have installed PostgreSQL and PostGIS on my laptop (Win 7 64 bit OS). I am running QGIS 1.8.0 on my machine . When I am trying to connect Postgis I am getting connection failed error then I tried ...
0
votes
1answer
239 views

Why postgis st_overlaps reports Qgis' “avoid intersections” generated polygon as overlapping with others?

I am implementing a postgis trigger on polygon layer to check and reject newly created polygon if it overlaps others. The problem shows when I digitize new polygons adjacent to others in Quantum GIS ...
1
vote
2answers
237 views

Postgis 2.0 - How to get a Point from given LinestringM and a measure?

If I have a cable route linear referenced and stored in a LinestringM with M value is the length (in meters) from the start of the route - for example: LINESTRING M (0 0 0, 10 0 20, 12 0 40, 20 0 50, ...
0
votes
2answers
69 views

Adding shp files to PostGIS in QGIS 2

I followed this tutorial to set up Postgresql 9.1 and PostGIS 2 on my Ubuntu Server 12.04. I also installed pgAdmin III on my Windows 7 client. I set up a database landarch and user chadmwade, ...
0
votes
0answers
137 views

Split lines at polygon intersection with attributes saving

This relates to this question but what about keeping the attributes. Having line_layer (id, geom, attribute1, attribute2) poly_layer (id, geom, attribute3, attribute4) How do I split the lines ...
0
votes
1answer
55 views

pgrouting 2: missing pgr_findnearestnodedwithin function

With the PgRouting 1.5 I was using the find_nearest_node_within_distance function and it works, but now I'm moving the project to PgRouting 2 + Postgis 2 + PostgreSQL 9.1, and now that function, I ...
0
votes
1answer
280 views

Pgrouting functions and geoms type not found. Install failed?

I have installed a postgresql 9.1 and postgis 2.0 from source. I couldn't launch this : # Add pgRouting launchpad repository ("stable" or "unstable") sudo add-apt-repository ...
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0answers
46 views

Selecting a bounded area within a raster

I am new to postgresql. I have imported a 256kb sample raster (.tiff) into postgres with tilesize 100x100. Now I need to select the area (rectangle) from the center of the image using sql query. Then ...
0
votes
1answer
145 views

How to run ST_Intersects on a geometry from text and an existing table

I am developing a location based application that stores longitude and latitude coordinates in a string. I then (using PostGIS 2.0) need to use these coordinates and run ST_Intersects on it with the ...
1
vote
0answers
42 views

Is it possible to have run-time dynamic table updates to visualization using javascript interacting with postgis and geoserver

I have an idea of/have seen implementations, of dynamic map retrieval/updating using wms on openlayers by using updates to a postgis database which was hooked into geoserver and having a refresh ...
0
votes
0answers
17 views

Can't connect QGIS 2.0 to postgresql 9.3 remote server with postgis 2.1 [duplicate]

I am trying to connect qgis to my postgresql server using the add postgis layer option in qgis dufour. I am not getting any details from qgis other then 'connection failed check settings.' However, ...
0
votes
1answer
95 views

Difference between azimuth degrees when i use st_project in postgis

I have two points p1 and p2. SELECT ST_GeomFromText('POINT(92.78488163381019 55.9757874622428)', 4326) as p1, ST_GeomFromText('POINT(92.78482645521103 55.97564239375992)', 4326) as p2 ...
1
vote
0answers
30 views

What is the best way to manage permissions as root installing postgresql and postgis?

I've encountered an issue numerous times where I lock myself out of my postgres installation as a result of modifying my pg_hba.conf file and therefore screw up my postgres installation because I ...
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0answers
104 views

Is the postgis layer option in qgis 2.0.1 Dufour two way? Was the spit plugin built in?

I am trying to install postgresql with postgis on a remotely accessed terminal only installation of ubuntu 12.04 that I want to use to connect to qgis 2.0.1 and hopefully have a two way transfer ...