1
vote
2answers
53 views

How can I speed up these queries

I am trying to make some calculations using PostGIS and PostgreSQL. There are 3 important tables : wbn, wgo and wvb. These tables have about 500.000 objects in them (geometries). The problem is that ...
1
vote
0answers
22 views

PostGIS 3D Extrude function

I selected buildings from OSM (which represents my city). I insterted a new column 'height' and I filled with a random number exactly number 2, so every building have 2metres altitude. Buildings are ...
1
vote
0answers
63 views
+50

Raster slightly displaced after exporting from PostGIS database

With the following queries I've exported a raster (GTiff) from my postgis database: 1.Creating a large object: WITH buffer AS ( SELECT id, ST_Buffer(geom,50) AS geom FROM ...
1
vote
1answer
30 views

3D functions with SFCGAL in PostGIS

I have this setup: "POSTGIS="2.1.2 r12389" GEOS="3.3.8-CAPI-1.7.8" PROJ="Rel. 4.8.0, 6 March 2012" GDAL="GDAL 1.9.2, released 2012/10/08" LIBXML="2.7.8" LIBJSON="UNKNOWN" TOPOLOGY RASTER" on ...
2
votes
2answers
40 views

Do I still have to use a template DB for PostGIS?

createdb mydb -T template_postgis Is this -T template_postgis still necessary in new versions of PostGIS? I never saw this db being different, it always has those 3 sql files you run there. Is this ...
1
vote
1answer
35 views

ST_Union to merge tables containing lines?

I have to build a street network with Postgis that will be used with pgrouting. I have two tables: 1) the_network (182 lines): is a MULTILINESTRING table. Having columns road_name (varchar) / ...
1
vote
1answer
28 views

Trying to understand / troubleshoot intersection behavior of postgis

I'm trying to calculate the percent of intersection between two polygons using postgis. I was able to do so successfully for 90% of my polygons, but about 1500 have very unexpected values. I ...
1
vote
1answer
28 views

Weird ST_Contains behaviour

I'm creating a polygon and then checks whether one of the origin points is contained inside the polygon. To my surprise, I get False (?!) What is wrong here? SELECT ST_contains(ST_GeomFromText('POINT ...
3
votes
1answer
56 views

Improve speed of PostGIS “nearest neighbor” query?

One of the features of the Python/Django/PostgreSQL web application I'm building is that a user will be able to see the 100 other users who are nearest to them, sorted by distance. I'm using PostGIS ...
0
votes
0answers
25 views

PostGIS: calculate width/length of rectangular surface

I have rectangular shaped surfaces (multipolylines) and I need to calculate the width and/or length.. they have a rectangular shape but they're not real rectangles. Is there a way to do this ?
2
votes
1answer
34 views

POSTGIS: function st_collect(geography) does not exist

I am trying to use some Geography functions, but I am getting an error that (all) functions are not existing. I have checked other Stackexchange posts (e.g. this one), but the solutions did not work ...
2
votes
1answer
61 views

Problem with matching a buffer in Openlayers and the same buffer in PostGIS query

I am using a buffer tool to create a buffer on my base map in Openlayers. In addition to creating and visualizing this buffer, I pass the center point and radius to a query. The query collects all ...
2
votes
1answer
77 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
votes
0answers
32 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 ...
3
votes
3answers
96 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
61 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
16 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
29 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
43 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
98 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
24 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
59 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
53 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
64 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
76 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
224 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 ...
1
vote
5answers
215 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
48 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 ...
3
votes
1answer
315 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 ...
0
votes
2answers
47 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
68 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 ...
6
votes
1answer
149 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 ...
1
vote
0answers
96 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
75 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 ...
1
vote
1answer
47 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
178 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 ...
0
votes
1answer
21 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 ...
1
vote
2answers
565 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
124 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
62 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
0answers
23 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 ...
1
vote
1answer
415 views

Having trouble connecting QGIS with postgres database with postgis extension

I am working on Ubuntu Precise with postgresql version 9.3 and postgis 2.0. After initially starting my postgres database and eventually getting permission errors that would prevent postgres from ...
3
votes
0answers
47 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. ...
0
votes
1answer
80 views

postGIS (?) - ST_Difference preserving attributes

EDITED QUESTION: PROPER SYNTAX FOR ST_DIFFERENCE BETWEEN TABLES? I have two huge polygon datasets from shapefiles, call them 'baselevel' coverage and 'deluxe' coverage. They each contain over 2.4 ...
1
vote
1answer
104 views

Is postgres 9.1.9 supported by ArcGis 10.1 Service Pack 1?

I want to install Postgres and Postgis. Now we use ArcGis 10.1 So I install Postgres 9.0.5 But there is not exist Postgis for this version. I try install postgis 2.0.3 But I fail(it is only 32 bit ...
1
vote
3answers
104 views

PostGIS intersect on insert?

I have a large amount of point data that I have in CSV form. I am able to insert it all into a PostGIS table no problem. What I want to do though, is split the data up on insert into multiple separate ...
4
votes
3answers
314 views

Very poor performance of QGIS and PostGIS2. User error or feature?

I have a large table in Postgis2. It has >500 million polygon, line and point features all happily living in there and the table performs brilliantly in other GIS. I am now trying to just add that ...
0
votes
0answers
57 views

osm2pgrouting can't get ways.the_geom srid

When I try to launch osm2pgrouting osm2pgrouting -file ~/Téléchargements/mayotte-latest.osm -conf /usr/share/osm2pgrouting/mapconfig.xml -dbname routing -user gisuser -passwd fred1490 -clean I get ...
2
votes
1answer
47 views

Compare features in PostGIS with updating attributes

I have two polygonal layers: "existing" and "modified". Attribute table of "existing" and "modified" layers have same column "feature_id" - number of feature. Please help me create query which write ...
3
votes
1answer
153 views

For which operations a PostGIS Geography index is useful?

I need to do KNN- and within-region queries for POI data. I store the POI locations in a geography column. Since I understand that ST_DISTANCE doesn't use the geography index, I added a geometry index ...