PostGIS is an extension for the PostgreSQL object-relational database that adds support for geographic objects.
5
votes
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72 views
How to sample a 3D raster along a 3D path (or 4D raster along 4D path)?
I have a 3d raster dataset of atmospheric variables (lat x lon x altitude). I would like to sample this raster dataset along a 3d path.
Any idea how I can achieve this, preferable with qgis or ...
4
votes
0answers
69 views
Assigning costs to a road network : use raster or vector?
I have a road network in a PostGis database (db_routing). In another database (db_environment), I have some spatial features of the surrounding environment (trees as points and water bodies as ...
4
votes
0answers
683 views
Union, Dissolve, Buffer — multiple layers, all in one step?
I'm a new user of Quantum GIS (1.7.3) and I need to repeat a task multiple times, so I'm wondering if there is a quicker way to do the following (with three or more polygon layers - each layer has a ...
4
votes
0answers
483 views
How to create a routable road network from Ordnance Survey data?
I've been following the "Beginners Guide to pgRouting" in an attempt to create an in-house application that provides drive-time isochrones.
I have a server, postgreSQL and PostGIS and pgRouting - no ...
3
votes
0answers
57 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: ...
3
votes
0answers
48 views
Where can I find PostGIS error codes?
Using ST_Contains in where clause sometimes gives me error messages like
ERROR: GEOSContains: TopologyException: side location conflict at 37.3706 55.7882
For now I can't guarantee validity for ...
3
votes
0answers
69 views
building larger polygons from smaller ones *without* a common id in PostGIS
I am looking for a means, using PostGIS, of reconstituting a set of polygons from tens of thousands of smaller polygon 'pieces'.
This is a simplified example, with the pieces shaded:
Unfortunately ...
3
votes
0answers
172 views
How to make working with Postgis vector layers in Qgis faster?
I have just imported a Spatialite database into Postgresql/Postgis. The problem is: using Qgis to work with them is much slower in Postgis (spatial indexes created) than doing the same in Spatialite.
...
3
votes
0answers
126 views
Geoserver WMS-T backend problems
I've been trying to set up a few timed WMS layers in GeoServer. They're simple enough, of the form
ID(PRIMARY KEY) REGION DATE VALUE
so for every region and date you have some value, e.g. the ...
3
votes
0answers
116 views
Exporting 3D geometry from PostGIS 2.0
I have a table containing 3D geometry in a PostGIS 2.0 database (the geometry is of type LINESTRING Z).
I need to get the geometry out and into a DXF, DGN or 3D Shapefile. What is the easiest way to ...
3
votes
0answers
133 views
Shortest distance from pgrouting with cost not being length: optimal solution
I'm using pgrouting shortest_path_astar with a complicated cost function. It gives back the edges, vertices and costs.
I would like to get the total distance of this shortest path (i.e., the sum of ...
3
votes
0answers
178 views
How to save table from PostgreSQL to MapInfo File?
I have two tables:
1 with geometry in WGS
2 with geometry in Local System
I tried this:
ogr2ogr -f "MapInfo File" output2.tab PG:"host=localhost user=postgres password=123456 dbname=postgis" -sql ...
3
votes
0answers
263 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:
...
2
votes
0answers
28 views
How to create a topologically correct dataset in PostGIS (with GRASS)?
I have shapefiles which I have loaded in postgis and now i am trying to use geometric function in postgis like ST_intersect and they fail because the data is not topological correct.
I have tried to ...
2
votes
0answers
21 views
Clustering table on geohash index and geohash ordered table
I wonder if there could be a performance gain to re organize the rows in a table by Geohash and then CLUSTER this table on the Geohash index of the geometries.
CREATE TEMPORARY TABLE tmptbl AS
SELECT ...
2
votes
0answers
50 views
Problem in importing raster data from PostGIS to Geoserver
I am using Opengeo Suite 3.0.2, PostGIS 2.0.3 and PostgreSQl 9.2.
I am trying to import raster data from PostGIS to Geoserver but facing an error.
I follow this tutorial link to import the raster ...
2
votes
0answers
47 views
Installing knn on PostgreSQL for windows
I am trying to install the extension KNN for clustering as an extension on my PostgreSQL database.
I have downloaded the file
http://www.pgxn.org/tag/analysis
I found instructions on how to ...
2
votes
0answers
16 views
Spatial overlay data from many lines into a single line
Hello I have joined lines in my data set into longer lines (based on similar attributes) to reduce the number of rows in my data set. Now I want to take the information from the original smaller lines ...
2
votes
0answers
50 views
assign_vertex_id：problems when creating the node ids
Before using pgrouting, I have to create the node ids.
I loaded my polyline layer into PostGIS Manager：
I type this in SQL query：
select assign_vertex_id('split_4', 800, 'geom', 'gid')
But as ...
2
votes
0answers
48 views
Get Multiple Shortest Path using PgRouting in One Query
I am trying to get multiple shortest path using A* Algorithm available in PgRouting.
I referred Solution given by UnderDark ( Link of the Stakoverflow Post ) . But it is not giving me proper Output.
...
2
votes
0answers
76 views
Extracting x,y,z values from a postgis linestring to python using ogr
I am trying to load a postgis linestring into python (using ST_DumpPoints) and extracting x,y,z coordinates, which is working but extremely slow..and if i mean slow, i really mean it (yes, it takes ...
2
votes
0answers
68 views
Storing features in PostGIS and then creating layers using queries
I have a whole set of line segments or tracks that represent real tracks or, in some case, boundaries between areas.
These segments form a network of lines on the map.
I have a number of GIS layers, ...
2
votes
0answers
51 views
How to Create database using OGC compliant geometries and Custom type Geometries?
I am interested in storing geometry attributes in a PostGis database, so that it would be OGC compliant, along with OGC compliant geometry types like point,line, linestring, etc. I also wanted to ...
2
votes
0answers
115 views
Geoserver, PostGIS and KML: Creating clickable nodes from OSM data
I have a PostGIS database that has OSM data imported into it using osm2pgsql and I'm using GeoServer to plot the points into a networked KML file for Google Earth.
What I'd like to do is make the ...
2
votes
0answers
28 views
Automatic insert of project name into database
For every layer I've a field in my postGIS database that should be filled with the name of the current project and today I do this manually.
Is there a way to do this with the Commands that can be ...
2
votes
0answers
82 views
Adding polygon to existing database column
I've built a database with postgreSQL with a few geometry columns.
When I add some data to my non-geometry columns, I can see them in QGIS when I connect to my DB using postgis. Now, I want to add ...
2
votes
0answers
56 views
Which is better for storage? Geometry column or varchar?
Objective:
Need to store and retrieve a list of geometries from the database. Basically these are drawn by the user using OpenLayers which I would like to save and present again as a list (kind of ...
2
votes
0answers
234 views
Hibernate Spatial 4 and Postgis 2.0
I'm having some issues integratings this technologies:
Hibernate Spatial 4.0-M1
Postgis 2.0.2 (with compiled jdbc 2.0.2)
Hibernate 4.1.1
The specific error is:
Caused by: ...
2
votes
0answers
93 views
How to import PostGIS layer with geography type to QGIS?
I tried to import in QGIS a layer from a PostgreSQL table with a geography type column created through the extension PostGIS.
I noticed that QGIS doesn't seem to like the geography column...
Here ...
2
votes
0answers
92 views
Creating Ellipse in WGS84, but with metric parameters
I have the function
--Ellipse(x,y,rx,ry,rotation,#of segments in 1/4 of ellipse)
SELECT ST_Translate( ST_Rotate( ST_Scale( ST_Buffer(ST_Point(0,0), 0.5, $6), $3, $4), $5), $1, $2)
I have points in ...
2
votes
0answers
141 views
Different results given by PostGIS and MySQL?
I'm developing a spatial database of administrative areas. I started out with PostGIS, but as MySQL is being used in our other projects, I thought I would at least try to create a spatial-enabled ...
2
votes
0answers
66 views
Problem with SPIT (error while importing layers to POSTGIS)
I was attempting to import a polyline roads layer into postgis, using both SPIT in QGIS 1.7 and postGIS GUI for this purpose. I have received errors through both processes as described here:
SPIT
...
2
votes
0answers
123 views
Projecting PostGIS in Openlayers
I have a layer(base layer) with MultiLineString Geometries and now I need to project the layers(overlays) in the base layer from PostGIS using OpenLayers.
However, I got an idea how to project table ...
2
votes
0answers
111 views
From pgRouting shortest_path back to osm node id
I'm successfully performing path finding queries like shortest_path on data imported with osm2pgrouting.
The tables I have inside my pgrouting DB are the following:
List of relations
...
2
votes
0answers
108 views
Is there a way to start the route on pgrouting from a coordinate that is not a node?
After execute all steps from this pgRouting tutorial, now I have a map that creates and displays routes, but as the routing methods rely on parameters representing vertex Ids that was created using ...
2
votes
0answers
91 views
Create a consistent topology using pgrouting
I'm developing an application that needs routing information for certain cities. First, I downloaded a openstreetmap datafile (*.osm) and then I imported it into a postgreSQL database using ...
2
votes
0answers
126 views
Postgresql Query Plugins Not Returning Results in QGIS
I'm using the Fishnet function as described here to create a grid.
If I use the following SQL to call the function to position a grid where I want it (I'm using NZGD2000 SRID = 2193) the query ...
2
votes
0answers
98 views
Displaying text from dxf in Openlayers
I managed to import .dxf into Postgis table, and now have, among others, rows with Point geometries and values in text column (which corespodent with Label values from ACAD .dxf).
What is the best ...
2
votes
0answers
66 views
MultiPolygon from database
I would like to know how to create an instance of a Multipoint from a PostGIS database..
I do the query , then got the ResultSet named "area" , the column with MultiPolygon attributes is named "geom"
...
2
votes
0answers
225 views
PostGIS: ST_Transform function conversion problem
I'm inserting map data from a GML file with srid EPSG:27700 into a PostGIS database table with srid EPSG:4326. I'm using the ST_Transform function as in this snippet:
...
2
votes
0answers
199 views
Parcel ID Mapping (brainstorming)
In my project I have a table full of residential properties by Parcel_ID. Table 2 is a TIGER streets shapefile. I would like to build a query in MS Access displaying all properties within a mile ...
2
votes
0answers
68 views
network related issues arising when running an arcpy script
Essentially I wrote an arcpy script that is within a toolbox that I ported over to a different machine to test out after the script worked locally.
The script essentially utilizes the psycopg module ...
2
votes
0answers
87 views
Symbolizing Layers from a PostGIS Database to many Client Computers
I was hoping someone could help with a symbolizing issue. I have a PostGIS database on a server with a number of layers. The layers of a series of polygons, lines and points that all share the same ...
2
votes
0answers
299 views
line segments using points
Is there a way to get line segments from a linestring using points with lat/lng coordinates?
ST_Line_Substring is taking float8 start/end points. Is there a way to replace the float8 with lat/lng? I ...
2
votes
0answers
253 views
Arc by center point in PostGIS does not fit the circle
I'd like to store a GML ArcByCenterPoint in PostGIS. I can work out the start, middle and end points required by the CIRCULARSTRING type and all seems to be OK, except that when I visualise the arc it ...
1
vote
0answers
31 views
An algorithm for locating candidate labelling boxes within a polygon
Has anyone implemented this algorithm In PostGIS? Quoting from the paper:
Vector-based geographic information systems usually require annotation, such as a polygon number or attribute data, in a ...
1
vote
0answers
29 views
Dynamic SLD styling based on min / max value in a PostGIS column
I have a PostGIS table that contains the GDP of countries together with their polygon boundaries. I am using GeoServer to display this data via OpenLayers.
When styling the data, I want to avoid ...
1
vote
0answers
27 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, ...
1
vote
0answers
55 views
How to get Lon/Lat values from the postgis raster type column
I have a tiff raster in my PostGIS 2.0 database. I want to get the value lat/lon and extra data like temperature from the raster type column in postgis table.
I want the table with columns ...
1
vote
0answers
61 views
How to add legend in WFS openlayers
How i can publish WFS openlayer with legend, have tried different examples such as http://api.geoext.org/1.0/examples/vector-legend.js. But when i used tried this fire-bug shows an error=> ...
