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

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4
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2answers
135 views

How to connect points (bus stops), which don't lie on the lines (LINESTRING), to a network?

I need to connect bus stops (points) to a network layer (OSM data). These bus stops do not lie directly on the lines (see screenshot) nor should their location be moved. I use PostGIS, pgrouting and ...
4
votes
1answer
421 views

How to create linestrings with a definite angle and length, that are fixed to a point

I want to create linestrings with a definite angle (e.g. 160°) and length (e.g. 2m) that are fixed to a number of points of another linestring. So, I want to use the ST_DumpPoints function to find the ...
4
votes
3answers
461 views

Loading raster data to postgis

I'm a newbie in GIS technology and need some help in loading a rainfall radar raster data into PostGIS. The raster image is shown here: What I need is to store in the database the radar ...
2
votes
2answers
88 views

How to create more networking osm

Using localhost page generated by osm2po roteamente noticed that the link is made to link even disabling snapping. Logically thought to create more nodes in the network, but how can I do this ...
2
votes
1answer
362 views

In what situations would SpatiaLite be selected over PostGIS, and vice versa?

I know that SpatiaLite is a lightweight solution. Would it be a problem if I put it on a 5K pageview/day site? Is PostGIS too resources-consuming for such usage? The dataset is something like < ...
2
votes
1answer
2k views

Why does ST_Transform fail?

I got a postGIS error like this, ERROR: transform: couldn't project point (100.496 13.7118 0): latitude or longitude exceeded limits (-14) SELECT ...
1
vote
1answer
252 views

Automatic bulk snapping with FOSS

I'm looking for a tool that would be able to automatically snap features closer than a given distance. Is there such a tool/plugin for QGIS/GRASS/OpenJump? Would it be possible to achieve that with ...
7
votes
2answers
762 views

Growing a PostGIS geometry by a percentage

I'm looking for a way to add a buffer around a PostGIS geometry, but the size of the buffer should depend on size of the geometry. That is, I want each geometry to be enlargened by, say, 5%. The idea ...
7
votes
1answer
1k views

How to perform a spatial join of point and polygon layers in PostGIS?

I have a point dataset representing households that I want to associate with a parcel layer (i.e. assign its parcel_id). With ArcMap, I could spatially join the polygons to the points and specify that ...
5
votes
2answers
658 views

PostGIS - area-weighted calculation on an intersection

I'm trying to learn postgis sql by performing some familiar operations from ArcGIS. Here, I want to perform an area-weighted calculation of certain populations on the intersection of a set of parcels ...
5
votes
1answer
239 views

Calculating path sinuosity in postgis

Sinuosity is a fairly straightforward concept. How can this be calculated in postgis given a series of linestrings that represent the path?
5
votes
3answers
1k views

How to create spider diagrams (hub lines) in PostGIS?

I'm rather new to PostGIS but I have done a lot of reading. One thing that I have been searching for is a function that allows users to create a "spider diagram" (also called "desire lines" or "hub ...
4
votes
3answers
453 views

How to efficiently find points within an elliptical area?

Using PostGIS 2.0.0 I need to filter the results of a function, which returns many POINTs, to find the ones that lie within an elliptical area defined by two points and a distance (all parameters ...
3
votes
3answers
194 views

How can I draw squares in PostGIS layers at different angles?

I am trying to draw two squares on a 45-degree angle and then merge them using PostGIS to edit. QGIS can draw squares but only on a perpendicular plane (eg, 0, 90, 180), and I need to be able to draw ...
3
votes
2answers
2k views

How do I use st_dwithin with meters?

I am trying to follow PostGIS ST_Buffer Radius Help to use a 50 meter distance but postgis is returning an error. I am trying the following SQL, SELECT id FROM table WHERE ...
3
votes
0answers
461 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: ...
3
votes
2answers
3k views

Postgis installation error

I am using fedora machine. I want to install postgis on my system. So this is what I have done Installed Postgresql and supporting packages using YUM. Created directory /sources to put all the ...
2
votes
1answer
61 views

Calculate distance between point and linestring and how to represent that on QGIS?

I have loaded my data with osm2pgrouting and I have my network with ways (Linestring) and nodes (Point). The problem is : I have a database of doctors addresses (point) and I should calculate the ...
2
votes
2answers
458 views

Postgis, get the points that are x meters near another point, in meters

I'm trying to find the points within a certain distance, in meters, from another point. I'm using the function ST_Buffer, but I don't get how to express the distance in meters. I'm trying with ...
2
votes
1answer
275 views

Unreachable vertex

I'm developing an application for academic purposes that mainly gives to the user a recommended itinerary for a previously introduced preferences (Gastronomy, Leisure,etc.). For this purpose, I use ...
2
votes
1answer
760 views

Why does my PostGIS query fail with “current transaction is aborted”

I'm trying to create a vector layer in a QGIS project using a PostGIS query. QGIS is returning the following error: Query failed 1 cursor states lost. SQL: CLOSE qgisf1 Result: 7 (ERROR: ...
2
votes
2answers
927 views

DatabaseError: Coordinate values are out of range [-180 -90, 180 90] for GEOGRAHY type

I am using Django 1.3, PostGIS 2.0 , Postgresql 9.0 and GeoDjango. I had a database with a table for places. This table had latitude and longitude for places in the US. I enabled this database with ...
2
votes
1answer
196 views

Automated correction of parcel geometry based on area measure

i have a set of parcels in DWG file and i have the areas that should be in these parcels in an excel file, so i have to modify each parcel to match the area specified in the excel file with a moving ...
1
vote
3answers
87 views

How to complete the roads output of PostGIS?

I converted the file I exported from OSM to PostGIS using osm2pgsql. I have opened the table's outputs to QGIS and I saw data are not complete compare to OSM editor view. Most of the roads are broken ...
1
vote
2answers
169 views

Searching planet_osm_point by longitude and latitude

I used osm2pgsql to import data into my PostgreSQL database and it put gave me the following 4 tables, planet_osm_point, planet_osm_line, planet_osm_polygon and planet_osm_roads. I have looked at ...
1
vote
1answer
121 views

Routing in MS SQL 2012

I would like to perform routing in MS SQL 2012 similar to pgRouting. In pgRouting, I'd do the following steps to create a routable network: Create a database routing with template template_routing ...
1
vote
1answer
560 views

How to Import ESRI Geodatabase format .gdb into PostGIS

I ran into a problem when loading a ESRI Geodatabase format .gdb into PostGIS. I have data 2.5GB GDB file. I followed some tutorials on the internet, but it seems that doesn't work out. I created a ...
1
vote
2answers
437 views

ST_DWithin uses Geometry or Geography type

assuming I use the following query to match the locations to a poi within 10km distance: SELECT poi.poi_id, h.loc_id, (ST_Distance(poi.geom,h.geom)*111.111) as distanceinkm FROM iut_poi_transl AS ...
1
vote
1answer
704 views

GeoServer WPS Aggregation Functions Example

The scenario: I want to present a user with names of polygons from a layer in GeoServer. I then display the polygon(s) whose name(s) the user selected. What I've done: I have a search box, which ...
0
votes
1answer
93 views

PostGIS: ST_Clip() raster in SRID:32617 with a polygon

I'm trying to ST_Clip() raster in `SRID:32617' with a polygon. What I did ST_Transform(polygon, 32617): It fails, couldn't project point() exceeded limit (-14) ST_Transform(rast, 4326, ...
0
votes
1answer
264 views

Coordinate values are out of range [-180 -90, 180 90] for GEOGRAPHY type

After import some data from OSM file into Postgre, the coordinates numbers are too big and having trouble to cast to Geography: Coordinate values are out of range [-180 -90, 180 90] for GEOGRAPHY ...
0
votes
0answers
79 views

not able to view imported .tif file in geoserver

I am using geoserver. I have imported a .tif file using postgis, which has been saved in vector type layer in geoserver. Now, whenever, I preview it, the layer gets automatically downloaded as wms ...
18
votes
7answers
1k views

Spatial databases learning resources for newbies

Would be taking up a course on spatial databases next semester. Would anybody know a newbie friendly introductory resource? A vendor neutral one would be preferable. Thanks.
10
votes
1answer
5k views

Geocode quality: Nominatim vs. PostGIS Geocoder vs. Geocoder::US 2.0

I occasionally need to geocode >> 500,000 US street addresses (no features or intersections). I'd like to set up a geocoding service locally to handle these bulk geocodes. I've used the Tiger-based ...
14
votes
5answers
1k views

Find pseudo nodes in free GIS software

Software gvSIG OA Digital Edition 2010 have tools topology for finding pseudo nodes in linear geometry. I set cluster tolerance 0.00002 and maximum number of errors -10000 for 20000 link count linear ...
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 ...
17
votes
6answers
3k views

How do I get started with GIS Servers on Amazon EC2?

Are there any tutorials, talks or presentations that discuss the use of EC2 or other cloud computing services to host GIS Servers? Has anyone had any experience in doing it with Amazon's EC2? How hard ...
16
votes
2answers
4k views

How can I find a point inside a polygon in PostGIS?

How can I find a point that is guaranteed to be within a given polygon in PostGIS? I am aware of the ST_Centroid function. However, the centroid is not always within a polygon, see below: ...
22
votes
5answers
8k views

Optimizing osm2pgsql imports for OSM data

I'm currently building an instance on EC2 on which to import the entire Planet.osm snapshot of the whole Earth's worth of data for some projects we're working on. I've spun up a large Ubuntu x64 ...
14
votes
2answers
1k views

How can I merge/collapse nearby and parallel road lines (eg. a dual-carriageway) into one single line?

I have a shapefile from OSM which contains all the roads within a city. Larger roads (like dual-carriageways) seem to have 2 parallel lines. I'd like to collapse / combine those into 1 line so I can ...
13
votes
1answer
993 views

Identifying topological relationships using PostGIS

I'm trying to perform a basic typology analysis using PostGIS. My objective is to find any polygons that touch other polygons. To do this, I thought the ST_GetFaceEdges would work (reference). I want ...
11
votes
2answers
1k views

How to calculate the angle at which two lines intersect in PostGIS?

I want to calculate the angle between two lines where they intersect in PostGIS. The starting point for angle calculations in PostGIS seems to be ST_Azimuth - but that takes points as input. My first ...
17
votes
2answers
1k views

Moving a PostGIS Installation

I have a simple question: I have a postGIS installation running on an old computer that I'd like to move. I spent a bunch of time playing with pg_dump and pg_dumpall without success. It seems the ...
12
votes
3answers
689 views

PgRouting - How to clip links when reaching max costs?

I have a polyline shapefile representing a road network and a second shapefile containing points. I would like to use PostGIS (presumably PgRouting) to identify sub-networks or service areas radiating ...
11
votes
1answer
554 views

Nearest Neighbor Grouped Selection in QGIS

OK - so I have an interesting problem I am trying to solve. I have a list containing over 100,000 points in lat/long format which I have imported into qgis. Now, what I am trying to do here is group ...
8
votes
4answers
793 views

What is the best web editor and server for postgis?

I'm looking for a web editor (similar to openstreetmap) that works with an map Server (postGIS). This should permit edit and create new structures on map. What is the best option? Can you help me? ...
18
votes
5answers
977 views

How to simplify a routable network?

I have a network graph that I need to simplify in the sense of reducing the number of edges. The idea would be to merge nodes that are located close together and remove the connecting short edges. ...
13
votes
3answers
1k views

Visualization of 3D shapefiles with Mapserver and Postgis

I'm wondering is there a way to visualize 3d data with mapserver? 3D .shp files are in postgis database, and I already connected mapserver to database, but with simple layer in mapfile.
10
votes
2answers
394 views

How to identify and simplify point clusters with regard to time in PostGIS?

I just started to work with spatial databases and I want to write a SQL(PostGIS) query for automatic generalizing of raw GPS-tracks (with fixed tracking frequency). The first thing I am wokring on is ...
10
votes
6answers
2k views

Should I use a CMS for my web mapping application?

For my web mapping app, I am using GeoServer as server, PostGIS as spatial DB and OpenLayers on client side (as well as other JS libraries). The map is composed of base maps and vector layers. One of ...