2
votes
1answer
20 views

View with sequence in QGIS 2.4

In postgres, I created a view with a sequence nextval() to have an unique id (called vid). I tried to vizualise this view in QGIS but it failed. It seems that nexval() causes some issue according to a ...
2
votes
0answers
39 views

How to get user and password of a PostGIS layer

I wonder if it is possible to get the user and password for a PostGIS database if they are stored in the PostGis connection information. I get the connection information at the moment from the ...
1
vote
1answer
63 views

How to change the postgresql table to support postGIS?

I have a postgresql database which there is the table have lat & long columns. The postgresql does install the postgis extension. My question is how can I change the table with lat & long ...
0
votes
0answers
45 views

Importing a Raster into PostGIS 2.1 (Windows 7)

I am trying to learn how to import rasters into PostGIS (2.1). I have read through all the material I can find on doing this and know that the recommended tool for this is the raster2pgsql tool. I ...
3
votes
1answer
44 views

How to use ST_HausdorffDistance (PostGIS, QGIS)

I want to snap the GPX-track to the road network as the image below shows. I found out, that "Hausdorff Distance" is exactly what I need and that it is usable with PostGIS. But unfortunately I have no ...
1
vote
1answer
66 views

How to transfer layer data from OpenLayers to PostGIS database or QGIS?

Supposing I have a created some layers in OpenLayers containing only Geometry Points, how do I transfer my data to a postGIS database? Is there a way to turn pure javascript/openlayers to a table in ...
6
votes
1answer
70 views

one label for two-lane roads (osm, qgis, postgis)

I labeled my osm-lines-layer (PostGIS) with symbols for primary roads and motorways. While the symbols for the primary roads are well placed - with enough distance between each - the two-lane motorway ...
1
vote
3answers
43 views

Disconnect QGIS from database without closing the whole program

I'm making PostGIS queries to a GIS database from python and I'm using QGIS to visually check the results of my queries, but every time I want to run a new query I have to close QGIS because it keeps ...
1
vote
3answers
98 views

How to export streets in a certain area from one shapefile to a new shapefile?

I have a shapefile with the roads from Europe and I want to export in a new shapefile only the roads from Greece. I tried to delete the other roads but there are too many and I have no attribute to ...
4
votes
2answers
98 views

Split lines at intersection points

I've got some linestrings covering a road network, and need to split them at the crossroads. Does anybody have any idea on how to do it? I'm using QGIS 2.4, with a Postgis 2.1.3.
2
votes
1answer
50 views

Positons from GPS lanes inside a polygon

i have a lot of lanes like the orange lanes at the below picture (latitude and longitude values). Now i need all values from each lane inside the red polygon. What is the easiest way to realize ...
0
votes
0answers
64 views

QGIS WFS Error - Could not commit changes to layer

I have a PostGIS database being served by Geoserver. I can load the layers I want into QGIS no worries; however whenever I try to edit the layer I get this error message: Could not commit changes to ...
8
votes
1answer
194 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 ...
2
votes
0answers
37 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
votes
1answer
30 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 ...
6
votes
2answers
342 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 ...
0
votes
0answers
23 views

Export qgis vector layer to PostGIS table using python

I've created script, which does bunch of stuff, and in the end, I would like to export it to postGIS table. What is easiest way to do such export using qgis api or sth. I dont want to write SQL ...
1
vote
0answers
37 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 ...
0
votes
0answers
21 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 ...
1
vote
0answers
23 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, ...
1
vote
0answers
44 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 ...
1
vote
2answers
95 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 ...
0
votes
0answers
19 views

Problem with Performance when accessing selected Features from PostGIS layers in QGIS using Python

I have 2 PostGIS layer in my QGIS project. They have about the same amount of data and a similar structure except that layerX has its PK on a single column and layerY has its PK on 4 columns. When I ...
1
vote
1answer
32 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 ...
2
votes
1answer
64 views

Export raster from QGIS 2.4 to PostGIS

How can I export a raster file out of QGIS (version 2.4) into a PostGIS database? I am looking for a module or python script.
3
votes
0answers
57 views

Problem with performance when loading PostGIS layer using pyQGIS

I'm having a question on loading a PostGIS layer into the project from my QGIS plugin. The code is like this: uri1 = qgis.core.QgsDataSourceURI() uri1.setConnection(str(host), str(port), ...
0
votes
1answer
62 views

Cannot load postgis layer from sql string in pyqgis

I'm trying to load a layer using the following code in qgis python console: sql = "(select the_geom, ID from mytable)" uri = QgsDataSourceURI() ...
0
votes
0answers
32 views

insert row into postgis query table in QGIS

I find I am using QGIS (2.4) more and more as a client for PostGIS database tables with geometry, but also for tables without geometry, partly because it's good just to use the one application and ...
1
vote
0answers
31 views

Query PostGIS database without creating primary key [closed]

I'm trying to query PostGIS database from QGIS DB Manager: select row_number() OVER(ORDER BY idx DESC) as id, p.*, * from table_1 join table_2 as p on "name" = "name" where row_number() OVER(ORDER ...
1
vote
0answers
43 views

Join/append multiple, identical polygon layers into a single layer whilst retaining all attributes?

I have run some analysis (zonalstats) on different raster layers using the same analysis polygons. I want to concatenate all these different layers together, i.e. retain a single polygon and have a ...
1
vote
0answers
52 views

Postgis / QGIS Snap Point to Line

I'm trying to snap points to lines in postgis for use in QGIS, but cannot get it to work. I have one line in my line table (although it was created by merging multiple lines together) and about 600 ...
0
votes
1answer
85 views

Conflicts while installing postgresql9.3-postgis2.1,QGIS and gdal-bin

I want to use postgresql9.3-postgis2.1 and gdal-bin parallel . I have refer instruction here for installing postgresql-9.3 on ubuntu 12.04. I have install qgis from here While installing gdal-bin it ...
2
votes
1answer
53 views

Delete duplicate polygon nodes with PostGIS

I'm trying to delete duplicate nodes from a shapefile with QGIS, but after running the tool to delete it, nothing happens and shows the same errors. I thought that maybe importing to postgis could be ...
3
votes
1answer
88 views

Get default values from PostGIS DB in QGIS 2.4 editor

One of my postgis tables tables automatically includes the nextval(xxx) in the edit feature form in qgis(and I think will also update ids of multiple features automatically). The other seems to have ...
1
vote
1answer
121 views

Simplifying Shapefile without risking Spatial Accuracy?

I am building a feature for a web application. Basically would use the ABS (Australian Business Statistics) data to render the regions on the Google Maps. I am able to implement the basic working ...
1
vote
1answer
38 views

I'm not able to save edited layer connected via PostGIS in QGIS

I have project and i was doing editing layers in QGIS. These layers are connected in QGIS via PostGIS. 1 layer of the 4 layers was saved correctly but other layers gave me error message. Error ...
2
votes
3answers
59 views

How to display a table with more than one geometry column in QGIS?

In PostGIS, it is possible to use addgeometrycolumn more than once on the same table. Example: I have one table "scenes" with many attributes, and 2 geometry columns: the_geom1 and the_geom2. select ...
1
vote
1answer
61 views

How to write a (memory) layer from QGIS to PostGIS?

I am looking for an "elegant" solution to write, from a python script, a layer from qgis and into a new table of a PostGIS database. I thougth that this might be solved by QgsWriteVectorLayer, but I ...
1
vote
1answer
59 views

Some items have coordinates switched when loading PostGIS layers in QGIS [closed]

I am having problem with strange coordinates switching when loading PostGIS layers in QGIS. First, I thought, that problem may be cause by the use of GROUP_BY feature in layer query, but later the ...
1
vote
2answers
41 views

How to extract a new linestring vector from a existing multipolygon in QGIS?

What I want to do: create a new line (named linestring in Postgis?) from existing multipolygon layer in Postgis. Purpose: once these lines are created, I'll run some distance calcs from specific ...
0
votes
0answers
63 views

How to create a vector layer from a GeoAlchemy2 query?

I'm currently developing a QGIS plugin where I mapped a PostGIS database via GeoAlchemy2. I wrote a function that returns results from a GeoAlchemy query but have no idea how to create a vector ...
0
votes
0answers
14 views

Why is there greyed dupplicated table in Add PostGIS Layers dialog in QGIS 2.X

Does somebody knows why PostGIS 2.X tables are duplicated and greyed in the "Add PostGIS Layers" dialog in QGIS 2.X.? One is coloured with geometry type recognised the other is greyed with unknown ...
3
votes
1answer
89 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 ...
0
votes
1answer
86 views

Converting a JOSM indoor map to QGIS

I have created an OpenStreeMap layer of the indoor of a bulding by following this tutorial: https://wiki.openstreetmap.org/wiki/IndoorOSM, since that is only a proposed tagging schema for indoor ...
2
votes
0answers
23 views

PostGIS query with input from point layer

I have a table of rivers in PostGIS, each river linking to its outflow. I also have a QGIS layer of some selected sources, and would like to select the entire river downwards from each source (i.e. ...
1
vote
0answers
45 views

Looking for free tools to automatically generate spatial data catalogue

I've recently inherited a whole bunch of spatial data (mostly shapefiles but some .gdbs) which relate to a bunch of different cities. I'm looking for a way to take an inventory of what data I've got ...
0
votes
1answer
76 views

QGIS to solve projection mystery in Postgresql

I downloaded some data from local agency. Per QGIS 2.2, I defined the projection to 'EPSG:3587 - NAD83(NSRS2007) / Michigan Central' in postgresql (maybe ArcMap). Data is in Postgresql 9.3. I am ...
1
vote
3answers
97 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 ...
0
votes
0answers
40 views

PostGIS points to multipoint error

I have a table on PostgreSQL 9.2 ("POSTGIS="2.0.1 r9979" GEOS="3.3.3-CAPI-1.7.4" PROJ="Rel. 4.8.0, 6 March 2012" LIBXML="2.8.0""). This is it: CREATE TABLE nearest_point ( id_nearest_point serial ...
0
votes
1answer
37 views

PostGIS Group By Error [closed]

I am performing a pretty simple query in PostGIS 2.1.1 from within QGIS 2.2 for Windows (using the DB Manager plugin). I have a table with many columns and I am trying to perform a Group By function. ...