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

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Modifying record of table with GeoTools?

I'm developing a GIS application with java. I use Spring RESTController and GeoTools. In client side(I use Openlayers 2.13.1), user modify a feature of wfs layer and want to update it in server side. ...
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Creating polygons from line segments using PostgreSQL and PostGIS

Is there a PostGIS function that creates polygons from multiple line segments? I want to convert the pictured thirteen lines to four polygons. All lines belong to the table "boundary" (gid, geom). ...
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How to fix broken geometry after joining features in PostGIS

I have a PostGIS layer I'm serving over GeoServer. It looks like this. Im using the PostGIS query to get a new layer with some grouped features: SELECT id, name, st_union(st_buffer(geom, ...
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42 views

PyQGIS - load PostGIS layer as editable

I can load a PostGIS layer on QGIS' map canvas but "Toggle Editing" button comes "inactive". How can I load vector layer as editable? The code given below loads PostGIS layer on map canvas & ...
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Perfom SQL queries in Python and process the result

I query column names from a PostGIS table with following Python code: colnames = [] sql_getcolumns = "select column_name from information_schema.columns where table_name='shp2py';" ...
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35 views

How to know if two geometric figures are approximately equal?

I would like to know how to determine if two geometric figures (the_geom) are approximately equals. By the way, I'm working with Python, PostgreSQL and Postgis I have the following geometries: ...
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1answer
21 views

How to view a postgis raster query in QGIS

I have successfully loaded a large number of .asc images (>2800 200x200 tiles) into a Postgres table with PostGIS 2.1 support. The new table appears in QGIS's DB Manager and I can add the whole image ...
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19 views

ogr2ogr postgres import: check if dataset exists

I have a PostGIS database which I update daily with ogr2ogr using CSV files. This works great. Is there a way to check whether the actual value of a column already exists in the table (e.g. ...
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1answer
19 views

Why prj2epsg cannot resolve PostGIS SRText?

In many places I have seen people referring to http://prj2epsg.org (here, here). I have used this service too, however, the service cannot uniquely identify an EPSG code alway. I understand that it ...
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21 views

Branching factor in River system?

I would like to find the branching factor for a river system. I have tried dissolving it then trying to find the branching factor but I'm not to sure how. So I have it from west to east like it ...
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14 views

Creating geodjango model with geometry field that can accept different projections

I am working on web application with GeoDjango and within the model (db table) RoadAxis I have geometry field or more precisely LineStringField where I need to store different polylines (road axis) ...
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18 views

How to join a WFS layer to a table in OpenLayers

So I have to bring up this old question How to join a WFS layer to a stand-alone table in OpenLayers I recently have to get this working, I have to join a WFS layer data from GeoServer using postgis ...
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22 views

Insert rows into CartoDB from code

I have a simple web page where i show my cartoDB map and a dataset. I want to know if there is any way to insert new rows into my cartoDB dataset from code, so external users can add points to the map ...
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1answer
36 views

How to cluster points into clusters of a maximum diameter in PostGIS?

I'm working with transit stops in GTFS. I want to group together stops (N~8000 for a medium sized agency in the USA) which are proximately related in order to reduce the number of dimensions but also ...
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42 views

Import shapefiles into PostGIS using Python with psycopg2

I want to import shapefiles to PostGIS using Python with arcpy & psycopg2 to connect to PostGIS. I don't want to use the existing shapefile loader nor ogr, just write my own import tool. My steps ...
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49 views

Can't import shapefile to PostGIS

Sorry if my question is double post with the previous. I have tried to browse but I think I still can't find the solution. I am using postgresql 9.4.1 and postgis 2.1(pg 94) and also qgis 2.4.0. All ...
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1answer
41 views

Speeding Up pgr_dijkstra using bounding box in PostGis2.0

I'm using PostGIS for the first time to calculate distances between two points, for a driving school booking system I am working on. I have loaded in all of the maps for Australia, but the query I ...
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24 views

suitable column Data-type for geojson data storage and processign in PostGis

I have a MySQL table with 2 columns, id, a unique geometry id, and GeoJSON stored as a varchar, eg, {"type": "Point", "coordinates": [116.4, 45.2, 11.1]} ...
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1answer
42 views

How do I create a spatial filter on a layer?

I have a layer that draws points in a PostgreSQL (PostGIS) database. The problem is, all points in the table are being drawn. I want to limit the points drawn to a spatial query. How do I limit the ...
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31 views

Problem with importing WKT to PostGIS

I'm trying to import WKT (http://polygons.openstreetmap.fr/get_wkt.py?id=2413177&params=0 - boundary of one of districts of Łódź) into PostGIS database and convert it to geometry. I've created ...
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15 views

set Default projection in postgis table

I've set the SRID 4326 for a table having geometry column, but when i insert a geometry without SRID, i get an error because no SRID specified is interpreted as -1 or 0, so how i can set a default ...
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61 views

How to create dissolved buffers in QGIS with PostgreSQL/PostGIS?

Creating a dynamic buffer in QGIS I use the following query: CREATE VIEW buffer40units AS SELECT gid, st_buffer(geom,40)::geometry(polygon, 31492) AS geom FROM point; Now I want to dissolve ...
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29 views

ST_Buffer with segment AND endcap parameters

Making a QGis plugin that buffers a line and I want to declare a high number of segments and a flat endcap. ST_Buffer(geom, 40, 25, 'endcap=flat') This doesn't work with both parameters entered, ...
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1answer
56 views

Map-matching GPS points to the road network!

I am quite a newbie in Postgres and Postgis so please be simple and clear :) I am trying to do a simple map-matching (or path-inference if you wish) of some GPS points. I am using postgres(postgis). ...
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30 views

Displaying KML data with a user selection

I want to web map some historical cyclones data which are now in KML files, file/year. So I want the user to select a year from a button and the KML files will be displayed on interactive map). I ...
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53 views

Create common vertexes between shared polygon boundaries in PostGis?

Given two polygon tables L1 (blue) and L2 (red) that share a common boundary but different amount of vertexes, how can one make the shared boundary identical (they should share the same vertexes) ? ...
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2answers
67 views

Can't connect to foreign SQL Server table from PosgreSQL using OGR_FDW

I'm using Windows 7, with PostgreSQL 9.3.6 installed and PostGIS 2.1.5. While I wish I could get everything into PostgreSQL, I can't and need to connect to another server running SQL Server. I need to ...
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1answer
23 views

QGIS GPS not editing offline database

I have a set of layers from PostGIS that I have converted to offline. I am attempting to edit them via GPS. If the layer is point data, then I can add in that data without issue. However when I go to ...
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19 views

PostGis - ST_AsRaster returning raster smaller than reference raster

I am trying to convert a point geometry to a raster using a reference raster: SELECT ST_AsRaster(my_points, ref_raster) FROM my_table This works fine except it is only returning a subset of the ...
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1answer
31 views

PostGIS: Is it possible to identify overlapping polygons in the same layer using their geomteries?

I have a single table containing the geometries of ~3 million polygons and I am looking to calculate the number of polygons that overlap with another. I know that you are able to do this in QGIS ...
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1answer
27 views

QGIS add layer not working

I have QGIS 2.8. I open up the database manager, connect to PostGIS, and then execute a query. The resulting query has an id column, a name column, a geom column, and a membership column. I click on ...
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31 views

PostGIS and Mobile Devices Maps

I'm still learning the world of GIS reading this Introduction to PostGIS. So far I understand things but since I have an idea that I plan to later work on, I found something that I didn't quiet grasp. ...
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Point Cloud footprint/wireframe layer - PostGIS

I'm using PDAL to import LAS files into PostGIS. The tutorial provided by boundless is great, and shows how to display the data in patches, but it doesn't cover displaying the table 'footprint'. I ...
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WMS problems Qgis server with postgis

I have installed qgis and qgis server on a windows server. My plan is to use qgis server to generate a wms. It works fine when I'm using shape files in my qgis project, but when I'm adding a postgis ...
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28 views

How can I select only the points in a mixed geometry column in postgis postgres

Table "public.eating_drinking" Column | Type | Modifiers --------+-------------------------+----------- osm_id | bigint | way | ...
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33 views

Calculate total line lengths within a polygon?

I have basically the same conundrum as How do i calculate line segment lengths within a polygon? but I'm working in PostGIS, not ArcGIS. Any pointers? This query seems to like it should work, just ...
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1answer
36 views

How do I calculate ST_Length in miles?

I am playing around with a map of bike lanes (so, lines) and trying to calculate the total number of miles of lane in each of a couple of regions. But I'm not even sure how to use ST_Length to ...
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39 views

How to import country administrative boundaries from OSM Planet to PostGIS Polygons

I need to import all world countries as polygons or multipolygons into PostGIS. Specifically, I need the administrative boundaries that are like this orange bubble around the actual land borders. ...
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1answer
26 views

PostGIS raster2pgsql problem

I ran into this problem in PostGIS: raster2pgsql -c -I -C -s 4326 -N -9999 -M -Y -F ./test2/*.tif rdem2 > rdem2.sql Processing 84/84: ./test2/dem2_4326_06_14.tif ERROR: ...
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1answer
47 views

Select points near polygon in Postgis

I'm trying to make a spatial query, but I think something is wrong with it: I have two tables, places (point) and cities (polygon) When I try to get the points within 500m to one point, there is no ...
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3answers
117 views

How to get extent of multiple geometries?

I can query a geometry extent like this: select ST_Extent(geom) from tableName; But sometimes I am querying geometries more than one. I am getting 5 points that different locations. So I wanto to ...
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1answer
28 views

I can't understand this ewkb type mask

I have the following ewkb strings from PostGIS: 01 01000020 E6100000 AECB9307F9D81240 0F2ADCE003704940 01 01000020 E6100000 7EAA0A0DC4920DC0 5AF0A2AF201F4440 I've been able to understand every data ...
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30 views

Find hotspot with highest density for two objects

I'm using PostgreSQL/PostGIS and I have an advanced type of query. My database contains two types of objects - let's say homes and crime. Is there a way that I can find the area with the densest ...
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29 views

How to create raster from table containing cell values in PostGIS?

I am having a table with integer values. These values are in between 0 and 2. I want to create a raster out of that table with integers as cell values. Or else how to create polygons out of that table ...
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1answer
22 views

QGIS Add PostGIS layer: restricting to single schema?

My primary PostGIS database has 12 schemas (schemae? TNIRN...), some of which have nasty-sized tables. The DB is on localhost, on my own machine. For the most part, the actual working tables are in ...
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31 views

POSTGIS query - extracting common point from polygon data

I have a polygon dataset and need to find the single common point where 3 polygons meet. I'm approaching this by creating duplicate tables and comparing them to the main one (polygon_table a). I've ...
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PostGIS Geography data type not displaying in QGIS

I am trying to display data held in the PostGIS Geography type on a map in QGIS. Whatever I do I can't get it to work. Here is the SQL that creates my data - a single point in London. CREATE TABLE ...
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1answer
67 views

How can I speed up a slow ArcGIS Server 10.2 - PostgreSQL (9.2) ST_Intersects query?

I am troubleshooting a slow st_geometry query in Postgres 9.2 that uses ST_Intersects--a basic Select from table where ST_Intersects type query. table_extent ...
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1answer
44 views

Postgis ST_Distance query returning inaccurate results

I am using the following query to retrieve records from a postgresql DB @services = Service.select("*, ST_Distance(services.lon_lat, ST_GeomFromText('POINT (lat lon)', 4326)) as ...
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65 views

GeoDjango: AttributeError: function 'GDALAllRegister' not found [closed]

Im trying to get started with GeoDjango. I am using this https://docs.djangoproject.com/en/1.8/ref/contrib/gis/tutorial/ tutorial. When I run "python manage.py migrate" This error occur: ...