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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3
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1answer
148 views

How to create a buffer on a linestring with varying or increasing/decreasing width

I want to buffer rivers/streams for a topographic map. I'm using a PostgreSQL/PostGIS database. Usually, I create buffer with ST_Buffer with a constant width. For example, the width of a river buffer ...
0
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0answers
71 views

Postgis performance: st_dwithin vs static buffer and st_contains

I have a table with a polyline column. I need to find which of those polylines are within 20 meters from a bunch of moving points. I can do this no problem with st_dwithin(). What I would like to know ...
4
votes
3answers
238 views

How to create random points in a polygon in PostGIS

I have a polygon layer, and would like to generate random points in each polygon. An initial searching in Google resulted this website which presents a function for this purpose: ...
1
vote
3answers
99 views

Geometry vs geography for line-to-polygon intersection

I have two WGS84 NAD83 shapefiles, one polygonal, the other containing lines: Geometry: Polygon Feature Count: 1294 Extent: (-79.761059, 44.991143) - (-57.105486, 62.582865) Layer SRS WKT: ...
0
votes
0answers
32 views

Transforming multiple LineStrings to shape for ST_Contains

I want to find cities, villages etc inside each region of Poland. For most of them querying something like this is enough: ... AND ST_Contains((SELECT way FROM planet_osm_polygon WHERE osm_id = ...
1
vote
1answer
52 views

ST_AsLatLonText returns wrong data

I want to list all cities in lubelskie vovoidenship, which is relation 130919. I also want to get latLong data for each city. To perform this I do: SELECT name, ST_AsLatLonText(way), place ...
1
vote
1answer
62 views

Problem with runing a loop in a query in PostGIS

I am new to PostGIS and I have a question which can't solve. I have a table of buildings each having a value for number of people living in it. I would like to calculate the total value (sum of number ...
2
votes
3answers
131 views

Problem with result of query in PostGIS

I run the following query and irrelevant of the point coordinates and radius I always recieve all the records of the table I'm querying. Can anyone point out what the problem could be with this query? ...
0
votes
0answers
25 views

Postgis and osm2pgsql: find all cities that belong to selected state [duplicate]

I'm pretty new to postgis, so I don't quite understand it's mechanisms yet. My task is to build database with relations: +---------+ +------------+ +----------+ | country | | adm_unit ...
1
vote
1answer
89 views

Problem with using a circle as polygon for querying PostGIS

I'm trying to query PostGIS and find some object features that intersect with a circular buffer created by the user using OpenLayers, JavaScript and PHP. I use the following code for creating the ...
2
votes
1answer
182 views

Problem with reading data from PostGIS as KML file using PHP

I am using the following PHP code in order to read data from PostGIS and save it in KML format as a file. When I load the page a document with ".PHP" extension is returned (not .kml) which inside has ...
2
votes
2answers
185 views

Problem in running query on PostGIS using PHP

Would you kindly help me solving this problem. I'm trying to use the PHP code provided here in order to read geo-data from PostGIS. The code seems clear without any problem (also nobody has ...
2
votes
1answer
377 views

Add PostGIS spatial functions to a custom schema other than “public” in PostgreSQL

I am new to PostgreSQL and PostGIS. Recently, I created a PostGIS 2.0.3 database on a PostgreSQL 9.1 database server using pgAdmin. The "PostGIS" extension was found installed in "Extensions". Al ...
3
votes
1answer
1k views

Loading Shapefiles into PostGIS using shapefile import/export manager

I am a complete beginner with PostGIS. I've started learning it using the tutorials provided by Boundless. In section 4 of this tutorial where I want to import shapefile in PostGIS, I do not have the ...
0
votes
1answer
81 views

Routing result not showed up [closed]

I'm following the http://workshop.pgrouting.org/ but my routing result not showed up at all, like the picture below: my firebug also didn't give me an error, I'm using geoserver 2.4.2, postgresql ...
1
vote
5answers
438 views

Problem installing PostGIS on Ubuntu Server 13.10

I've installed PostgreSQL 9.1 and postgis on Ubuntu Server 13.10 as follows: sudo add-apt-repository-ppa:ubuntugis/ubuntugis-unstable apt-get update apt-get install postgresql-9.1-postgis then I ...
2
votes
1answer
55 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 ...
4
votes
1answer
173 views

POSTGIS SQL - How do I remove (defined) sliver polygons

I would like assistance in writing SQL (for POSTGIS in postgresql) to remove sliver polygons (including long narrow slivers and some small irregular polygons that were erroneous 'gaps' in the original ...
3
votes
1answer
761 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 ...
2
votes
1answer
246 views

PostGIS: How to ST_Clip() a raster with a polygon?

I have done: Import a SHP file into PostGIS by PostGIS SHP loader GUI. Import a raster into PostGIS: \raster2pgsql -I -s 4326 landsat.TIF -t 500x500 public.landsat > query.sql After importing ...
0
votes
1answer
144 views

Python Geoserver gsconfig create resource from Postgis store table

I've working Workspace and PostGIS store in GeoServer. I would like to use python and gsconfig to create new resource/new layer from existing PostGIS table, with: computing bbox, adding abstract, ...
1
vote
2answers
85 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
141 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
74 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
49 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
55 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
1answer
79 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
62 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
239 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 ...
0
votes
1answer
54 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
274 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 ...
1
vote
0answers
119 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 ...
1
vote
0answers
183 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
168 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
84 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 ...
5
votes
0answers
90 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 ...
0
votes
1answer
77 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 ...
1
vote
1answer
51 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
326 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
371 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 ...
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 ...
2
votes
2answers
1k 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 ...
1
vote
2answers
200 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
0answers
96 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
2answers
66 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
1answer
51 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 ...
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vote
0answers
80 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 ...
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vote
0answers
41 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
241 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 ...
0
votes
0answers
46 views

Django application “GeoNode” gives message “DLL load failed” on windows

I'm trying to install GeoNode which is a Django application on windows through these simple steps on this page. I've reached a point where is the GeoNode is installed and I've created my postgres ...