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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1answer
208 views

Travelling salesperson in pgRouting without starting point

I'm a beginner with PostGIS and it's the first time I try pgRouting. I work for a regional transit agency and I'm trying to develop a mean to evaluate the easiness or difficulty to offer a bus ...
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0answers
117 views

Routing from individual start point to individual destination point

I'm doing routing on android using OpenStreetMap. The routing is working well. But the problem is that I do not know how to use the individual points of the user. I use osm2po to convert the OSM data ...
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3answers
435 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 ...
2
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1answer
885 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 ...
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2answers
392 views

How join attributes for point feature from nearest points in road network

I have two layers: 'linear' - road network and 'point' - points in each linear features intersections. Point layer have in attribute table name for each point features: A,B,C,D,E,F, etc. How add in ...
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0answers
114 views

PostGIS raster functions aspect and slope slow

I am trying to compute the raster and slope values from a DGM table (8184 x 5159) imported from tif file tiled in 500x500 tiles. In my query in which I merge the DGM table with a vector (point type) ...
2
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0answers
163 views

Hitting Memory Limits of PostGIS ST_ConcaveHull / Incomplete Shrink Wrap

I am trying to use PostGIS 2.0 on Postgres 8.4 to do some mapping. I am working with the NOAA Shapefiles, specifically their US States & Territories file located here: ...
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1answer
183 views

Help loading Raster to PostGIS 2 .0

Similar questions have been asked, but since my reputation is not enough I am unable to comment on answers. (The following is from an answer by nickves for this question Loading raster data to ...
2
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1answer
57 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 ...
2
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1answer
76 views

How to compute the distance from the beginning of a line for every points using postgis

I have a line, for which I need to know, for every point that compose it, what is the distance from the beginning. The data is stored in PostGis 2.0 For example, for the line with the point a, b, c, ...
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1answer
800 views

How to find the intersection point of polygon geometry and multilinestring geometry in postgis

I have a polygon geometry and multilinestring geometry. How do i find the intersection of both these geometries. Both the geometries are in same reference system. Does st_intersection gives me the ...
3
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1answer
59 views

Speeding up raster to point set function

I have written the following function that takes a raster (always non-skewed) and returns a set of points. As I'm executing it millions of times in my queries, I'd like for it to be super-optimized ...
3
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1answer
367 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 ...
2
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0answers
56 views

Optimize ST_CoveredBy performance

I have a PostGIS 2.0.3 table with 113,862 records with multipolygons represented both as geometry and geography. There is a gist index on each of them. I'm running the following queries: SELECT *, ...
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0answers
60 views

pgRouting Win 7 installation problem

I have run into a problem installing pgRouting. Following Anita Grasers guide, I have gotten as far as to execute the three .sql files. The first sql file (routing_core) runs fine, but for the second ...
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1answer
255 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 ...
0
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1answer
48 views

Difference between st_length() and st_m()

My question is about the differences between st_length() and st_m() in postgis. The reason I ask this is because in a MultiLineString I can´t calculate st_m(), but I can st_length(). Thanks.
3
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1answer
82 views

Force a collection of unknown number of points to be a polygon

I am working with point clusters and want to create the rough shape of the cluster in the form of a polygon using ST_ConvexHull(). I'm having problems with single outliers though, as they don't ...
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2answers
49 views

Does OSM2po handle squares and places?

OSM2po is converting data from OSM to postgresql. But how is it handled with places or squares? Not every places, square has pedestrian way routes on it. But for routing I need nodes and pedestrians ...
0
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1answer
250 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 ...
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1answer
447 views

how to split a line by a point which is on the line but not in the linestring itself?

i need some help with the following: i have a linestring - geom i have $lat,$lon (using some php syntax) i have an osm table with the roads geom, i am trying to get closest point, and then split ...
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0answers
117 views

Working with ambiguous AddGeometryColumn functions

I'm using PostGIS to add geometry columns to tables, but keep receiving the error: ERROR: function addgeometrycolumn(character varying, character varying, integer, character varying, integer) is not ...
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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.
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0answers
46 views

How to load a raster from in-memory bitmap (not from file) into PostgreSQL

I have a bitmap in memory that I would like to load as a raster to PostgreSQL. An unfavorable option is saving the bitmap to file and then use raster2pgsql, but as we have several cameras that ...
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0answers
76 views

Unable to Add Features to PostGIS Layer in Quantum GIS 2

I am testing out Quantum GIS 1.9-master and I've noticed that I am only able to add features to a PostGIS 2.0 layer if that layer is in a schema with the same name as my login. For example, if my ...
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2answers
481 views

ST_Touches for more than just one geometry

I'd like to select some neighbor polygons with ST_Touches. Therefore I found the following statement: SELECT b.name FROM layera as a JOIN layera as b ON ST_Touches((SELECT a.geom FROM layera as a ...
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1answer
513 views

How to populate the geometry column in a PostGIS table?

After loading a polygon shapefile into PostGIS, the geometry column (geom) is blank for several features. In one case, only a single feature has the geometry calculated and all others are blank. I'm ...
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2answers
358 views

Start postgresql+postgis without installation on Windows

I have used Windows7x64 and want start PostgreSQL+POSTGIS without installation process. I copy PostgresSQl\9.1 folder from other laptop to c:\opt. I need create .bat file with enviroment variables and ...
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2answers
606 views

Trigger to fill attributes (data, client ip) in table for each new objects, PostGIS

In PostgreSQL/PostGIS database stores shapefiles. Client users software - QGIS. Please help me write PostgreSQL/PostGIS trigger, which for each newly added/updated feature in layer added 'time create' ...
0
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2answers
216 views

PostGIS, distance between two users

I have a simple table (location_test) with three column (name, geom , jid). geom is a geometry column with SRID 27700. I set the user's geometry position with: UPDATE location_test SET geom = ...
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1answer
74 views

How to speed up query through view in postgis?

I want to set up a postgis database that have some base tables, then the users interact with them through views (which restrict their viewable and acessible regions). The server runs PostgreSQL 9.2 ...
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1answer
200 views

How do I convert MultiLines to MultiPolygons using Postgis

In postgis I'm using the following query to buffer lines to polygons: UPDATE rivers SET poly = ST_Multi(ST_Buffer(lines, 0.01)) where id = 1; The column 'lines' is a MultiLine and the column ...
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0answers
128 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, ...
2
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1answer
449 views

How to connect Postgis database with/in Remote Servers…?

I am preparing a 'Web based map' application using 'Geoserver-Openlayers-Postgis'... Now, I am trying to connect my Postgis database(located at 10.50.110.11 location) with the following command from ...
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0answers
31 views

error in loading raster tiles on postgreSQL [duplicate]

I am trying to import raster data from PostGIS to GeoServer. I follow the instructions given on this link. ...
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3answers
601 views

Snapping start- and end nodes of lines to other lines in PostGIS

There are plenty examples that show how to snap lines to points, but I haven't been able to find any (fast!) way of snapping the start- and end nodes of line strings to nodes of other lines. ...
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2answers
247 views

Emergency Services: How to optimize routing by measured travel time?

I would like to optimize the service areas / catchment areas for an emergency service. Therefore, I have several measurement points on the streetmap, where people have stopped the travel time from ...
5
votes
1answer
513 views

How to install PostGis on EC2 micro-instance

I tried to install PostGIS on my Amazon EC2 microinstance using sudo yum install postgis2 and got following error message: $ sudo yum install postgis2 Loaded plugins: ...
2
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1answer
207 views

Calculating points in the USDA's Cropland Data Layer coordinate system

I need to integrate against the USDA's cropland data layer. They've got a demo and some API docs. The important query I need to run is this, given an (x, y) of say (1551459.363, 1909201.537): ...
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1answer
103 views

Getting a “java.lang.OutOfMemoryError” error while importing raster files from PostGIS to Geoserver

I am trying to import raster data from PostGIS to GeoServer. I follow the instructions given on this link. ...
2
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0answers
238 views

operator does not exist: geometry <#> geometry

I'm running PostGIS 2.0 for PostGreSQL 9.2, and I have a customer who wants to know how close a provided geometry is to the nearest feature in a table. So I'm playing around with the "<->" and ...
2
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1answer
198 views

Are there strategies for dealing with TopologyException errors in PostGIS 2?

Are there strategies for dealing with TopologyException errors in PostGIS 2? Nearly every function I run against two geometries results in a TopologyException (e.g. ST_Intersection, ST_SymDifference). ...
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1answer
1k views

Postgis 2: Polygon/MultiPolygon in a single column

Storing MultiPolygon and Polygon features in a single column used to be as simple as not creating or removing the geometry type check constraint. Is there a similar simple fix in PostGIS 2?
0
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1answer
163 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 ...
3
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1answer
132 views

How can I check if a multipolygon can be represented as a simple polygon?

I have a large (30m+ records) spatial data set I have imported into a PostGIS database. I did not expect to find multipolygons in the data set, but it does have a few of them. I'd like to take a ...
3
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2answers
2k views

PostGIS: Convert meters to arbitrary spatial reference units?

I'm writing a query that needs to be able to work with data of any SRID. The basic problem is very simple - I get two pieces of information: A point (SRID = 900913) A distance (unit = meters) I ...
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1answer
374 views

How can I make a Postgres/PostGIS ST_Distance_sphere query more efficient?

Within Postgres/PostGIS I have written an SQL query to get the closest distance for each element within a point coordinate table from a polyline table. The query comes back and works correctly, but ...
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1answer
339 views

tinyows failing to connect to postgresql - Ident authentication failed for user “postgres”

I'm getting the above error on a new and local tinyows installation on Centos 6. Postgresql 9.2, PostGIS 2.0. I can connect to PostGreSQL locally and from my LAN using several other methods (psql, ...
2
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1answer
239 views

Cannot find my schemas in QGIS's “Add PostGIS layers”

When I connect to my PostGIS database using QGIS's Add PostGIS Layers, I see only public topology pg_catalog information_schema My other schemas that I have created are not shown here. Anyone else ...
1
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1answer
782 views

How to split line layer at polygons' boundary of a polygon layer?

I have a line layer and a polygon layer in PostgreSQL 9.2, PostGIS 2.0. How can I split every line each time it crosses a polygon's boundary?