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

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15
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1k views

Can PostGIS and QGIS provide dependable multi-user editing?

After considering a few options, I'm trying to give my 15-20 QGIS 2.2 users the ability to concurrently view/edit one or two basic point PostGIS layers, largest one has just 16,000 records. I've ...
3
votes
1answer
409 views

QGIS There isn't entry in geometry_columns!

In PostgreSQL v9.3 with PostGIS v2.1 extensions I created a view from two tables (sites & visits). The site table contained a point geometry column (the_geom), which was included in the created ...
0
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258 views

Find correct SRID

I'm learning PostGIS raster, and importing GeoTiff with raster2pgsql. This command line tool states: -s <srid> Set the raster's SRID. Defaults to 0. If SRID not provided or is 0, raster'...
9
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1answer
238 views

Point sampling along a pole-wrapping coastline with PostGIS

I am working on a task that requires me to get sample points every 1000 km along coastlines, and have run into a problem with Antarctica. From what I can tell, it seems to be an issue with the use of ...
2
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1answer
70 views

Why does the earth drop off faster than expected over a geodesic when converting from lat/lon to cartesian coordinates?

In PostGIS 2.1.1, I've been plotting elevations from a raster over distances, but noticed that beyond 1km, the earth's curvature seems to be greatly exaggerated. In this example over a 40km geodesic ...
2
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1answer
619 views

Building web application to get PostGIS query from user and view result map using GeoServer via OpenLayers?

I'm a newbie in web-map application area. I just found the small application in this tutorial interesting I am a bit confused, because when i publish a map using geoserver and openlayer, I have to ...
2
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1answer
191 views

Databases supporting intersection of multipolygons and a set of points

Currently we use PostGIS to store thousands of MULTIPOLYGONs and we can then use ST_Intersects to return any that rows contain any point in an input collection of points. Are there any other open ...
0
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1answer
141 views

Ubuntu QGIS 2.4.0 SSL connection to remote PostGIS fails b/c can't specify certificates

I can connect with SSL in PGAdmin to my remote server, but it requires specifying the filepaths for certificate files due to my having different certs for different servers. However, when connecting ...
8
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2answers
1k views

Using ArcGIS and QGIS together in multi-user editing environment?

We have a GIS staff of 7, and another group of about 14 who "use GIS" from time to time. We really, really want multi-user editing. Mostly of a large point file, and we're almost never in the same ...
5
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2answers
849 views

How can I extract all distinct values from a PostGIS Raster?

I am working with an integer raster in PostGIS 2.1 and I would like to extract all distinct values in that raster. I was hoping to be able to do something along the lines of the following query, but I ...
2
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0answers
165 views

List of vector to one raster in PostGIS

Hi PostGIS developers! I need to rasterize a part of OSM map by coordinates. I found rather good algorithm, but can’t finish it. I have problems in STEP 3. I described all algorithm here – may be ...
1
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1answer
171 views

What do pixeltypes in PostGIS raster mean?

I'm trying to build a raster in PostGIS from a vector layer and I was curious as to the meaning of pixeltypes in the raster geometry? How does it effect my raster?
0
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1answer
118 views

Run pgr_createTopology() on custom geometry(linestring) table

How could I create a topology for a custom generated geometry table having just the_geom geometry(linestring) column? Because pgr_createTopolgy() asks for the gid column also for a given table, which ...
2
votes
1answer
116 views

Find a path between an origin and destination given scattered points

We have a postgis database containing a lot of ordered (by date/time) nautical point (lat/long). Each of these points are affected to a leg between an origin and a destination (both origin and ...
1
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0answers
38 views

From QGIS to PostGIS [duplicate]

I want to download my data from QGIS to an existing table in Postgresql. I tried to use DB Manager, but the field add to existing table doesn't work. Maybe somebody knows what the problem is? Or is ...
2
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3answers
1k views

Configuring SFCGAL to PostGIS Db

I was using PostgreSQL with PostGIS and Pgrouting. Recently I needed to install SFCGAL for some extra functions for my PostGIS db. After installing SFCGAL, now I don't know how to update my PostGIS db ...
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0answers
181 views

Create geometry column of type 'PointZM' in PostGIS

I want to add a geometry column with geometry like "PointZM", "PolygonZM". I have written something like this: SELECT AddGeometryColumn ('data_rivne','geo_point','geom2',0,'POINTZM',0); But it ...
11
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2answers
652 views

How to compute the smallest network that connects all points using PostGIS?

I have a set of postgis scripts which generates two tables - one of a set of points and the second a set of roads which surround them. All data is in the same projection and both outputs are stored in ...
2
votes
2answers
679 views

Collecting multipolygons into a single multipolygon with ST_Collect() in PostGIS

I would like to collect 50,000 individual multipolygons into one big multipolygon. Unfortunately when I perform ST_Collect(geom) it bundles them into a geometry collection and cannot be cast as ::...
11
votes
1answer
3k views

How to use ST_DelaunayTriangles to construct a Voronoi diagram?

With PostGIS 2.1+ we can use ST_DelaunayTriangles() to generate a Delaunay triangulation, that is a dual graph of its Voronoi diagram, and, in theory, they have an exact and reversible conversion. ...
2
votes
1answer
98 views

PostGIS query losing geometry column information

Using PostGIS I want to collect all attributes into one polygon. The old table looks like this: Column | Type ---------+------ xyz_cols | `xyz` geometry | geometry(MultipolgyonZ, 2193) Performing ...
1
vote
2answers
502 views

How to validate OpenLayers area calculation using PostGIS?

I am working on a GIS API that work on top of OpenLayers. I have a feature that calculates the area of a drawn polygon. I have tested it on the browser and the areas I got, appear to be correct. For ...
2
votes
2answers
180 views

Did I set up Tiger Geocoder incorrectly?

I set up Tiger Geocoder in PostGIS on my local box (PostGIS 2.1.3, PostgreSQL 9.3.5, Tiger 2013 data). The problem I'm running into is that on almost every street most of the points are clustered, ...
0
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0answers
160 views

R PostGIS convert SpatialPolygon to PostGIS table

I've been having some success in scraping some webdata and converting it from HTML to spatial data as originally asked here: Parse PHP/HTML to shapefile or similar I've been using R to both fetch the ...
5
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1answer
1k views

Extracting centerline of a Complex-Polygon in PostGIS/Python

Any idea how to extract the centerline of the following polygon (Fig1) using PostGIS functions or Python modules? I was trying Voronoi Function but thats not helpful for this kind of shape. I want ...
2
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0answers
323 views

N Nearest Neighbours efficiently PostGIS/Python

The data is worldwide about a million points, lat/lons, with an id and an importance value (0.0 to 1.0), and it's limited to being on land. Ideally I need to cluster all 1 million points into 100,000 ...
3
votes
1answer
385 views

PostGIS: Get closest point between geometry and Multipoint

I think my question is not that difficult for GIS professionals, but i didn't found an answer to my problem (even not in other questions). Problem: I have given two tables (table1,table2) with Points ...
2
votes
1answer
234 views

PostGIS - How do I create a line that directly connects two earth points without travelling over a geodesic?

In PostGIS 2.1.1, I've noticed that if I create two distant earth points with equal altitude and then create a line connecting them, as I gather interpolated Z coordinate data along the line my Z (...
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0answers
140 views

Convert multiline to polygon

perfect result Shapefiles How I can convert this closed line to polygon with PostGIS? I tried many functions like ST_Polygonize, ST_MakePolygon, ST_BuildArea. I got some results, but not a perfect ...
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0answers
285 views

Finding areas with high POINT density from PostGIS table using Python

I have a PostGIS table with thousands of POINT objects and I want to find areas that have a high density of points. I have the DBSCAN clustering algorithm implemented in Python which does exactly that....
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0answers
77 views

Why does the postGIS file lose geometry?

I am loading shapefile data from a GPS into PostGIS via Leica ZenoOffice. This apparently imports fine with it's geometry in the attribute table. However, when I add a postGIS layer in QGIS the file ...
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54 views

GDAL_Translate not compressing when NoData value is set

I am trying to compress a .TIF file using GDAL_Translate or GDAL_Warp. My Raster is 32mb to start with. When I use GDAL_Translate with the COMPRESS=PACKBITS option, it compresses to 1.9mb. However ...
4
votes
1answer
264 views

Should geometries be drawn using rhumb-line or great-circle paths?

I work with WGS-84 coordinates and, most of the time, my map display (luciadmap) is in Mercator projection. My client is surprised to see that, for a rectangular geometry: the line between the 2 ...
1
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0answers
61 views

Create “grid” of polygons with the same 3D area based on an underlying raster variable (e.g. DTM height)

This could apply to point or raster values but imagine a raster of a continuous variable such as height (DTM). Is there a way to create a complete coverage of polygons that will have an equal area, ...
2
votes
1answer
119 views

Error in installing PostGIS 1.5?

I am installing PostGIS 1.5. After giving the command ./configure, it is showing that: pQserverversion in -lpq not found. configure: error: could not find libpq. What does it mean? I am ...
1
vote
1answer
53 views

How to calculate the intersection between WFS layer and a PostGIS table

I need to calculate the intersections betweek a WFS layer and the geometries stored in PostGIS table. Then I should save the geometries of the intersections in a separate PostGIS table. Do you have ...
1
vote
1answer
204 views

Error when trying to visualize geography data with QGIS

I use PostGis, and want to use QGIS to visualize data. But I get error message when trying to show the points in the table. I create a table: CREATE TABLE poi ( id text NOT NULL, coord geography(...
2
votes
1answer
306 views

PostGIS - How to do ST_UNION on each feature of a geojson FeatureCollection

I have a simple geoJSON featureCollection composed of 2 features: featureCollection = {u'type': u'FeatureCollection', u'features': [{u'geometry': {u'type': `u'MultiPolygon', u'coordinates': [[[[-...
1
vote
2answers
1k views

Export polygon in geojson as multipolygon

Anyone knows if is there any way to export a polygon layer in geojson, as multipolygon? I have a multipolygon shapefile. But there are single and multi polygons. When I export it to geojson, I got ...
1
vote
1answer
45 views

Error while installing PostGIS 1.5

After giving the command ./configure, it is showing that: pQserverversion in -lpq not found. configure: error: could not find libpq. What does it mean? I am using Red hat Linux (32 bit) version ...
0
votes
0answers
229 views

WFS with authentication to PostGis (or to shape)

Is there a way to import data from a WFS layer to a Postgis table (or to a shape)? there are blogs explaining how to do it in 3 steps (http://anitagraser.com/2012/09/26/wfs-to-postgis-in-3-steps/) or ...
2
votes
2answers
322 views

PHP examples to replicate FeatureServer capabilities

I used FeatureServer before and I liked it. The only thing I didn't like, though, is that it needs some other dependencies to work. That's why I want to try PHP instead. I know that there are already ...
4
votes
2answers
449 views

How to get the regional maximum or minimum of raster data by using PostGIS?

If I have Mean sea surface pressure data in raster format, is it possible for PostGIS to look for regional maximum or minimum? So that I can locate the L or H as the chart shown below? (image source: ...
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0answers
85 views

Which type in entities for PostGIS/Hibernate Spatial

I already manage to store, read and update PostGIS rows with Hibernate Spatial with a Point and a MLineString in a very simple case : a MLineString defining a road, display a point along this road ...
2
votes
3answers
206 views

Find point close to points from postgis table

I have a postgis point table with a large list of cities. I need to find duplicates in it, but only if they are 10km close each other, which means that is the same city. For example, I have 5 points ...
1
vote
1answer
100 views

Geometry error in roadnetwork

I have a road network table. When I check st_isValid(the_geom)='f', I am getting an error: NOTICE: IllegalArgumentException: point array must contain 0 or >1 elements ERROR: Exception in ...
1
vote
2answers
641 views

How to process GeoJSON data and create hive table for spatial analysis

I am using the ESRI-GIS tool for hadoop for analyzing json data generated through ESRI products like ArcGIS. But I wanted to analyze spatial data from a PostGIS table for which I made geojson ...
1
vote
1answer
416 views

Passing options to ogr2ogr using python subprocess.Popen

I'm trying to programmatically import some shapefiles to PostGIS, since I need to catch the exit code of the process I decided to use subprocess.Popen. I've managed to import the files using: cmd = ["...
2
votes
1answer
495 views

Migrating data from Python to PostGIS

I have pandas DataFrame with these columns: point datetime value 1 Point(-24.6064453125 26.3683280945) 2014-09-11 19:00:00 24.885258 2 Point(-...
2
votes
1answer
919 views

Get a single cluster from cloud of points with specified maximum diameter in postgis

I have on the order of 2M Geometry Collections with N (median: 2, stddev: 6.6, 75th: 6, 95th: 21) Point objects (repeated points allowed and important) in a PostGIS table. I want to identify clusters ...