QGIS is a cross-platform GIS application licensed under the GNU General Public License.

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QGIS freezes using MMQGIS plugin

I have a problem with geocoding addresses (about one thousand). I have a file (.csv) with a large number of addresses: street, house number, ZIP code, city. I used the mmqgis plug, but after geocoding ...
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1answer
42 views

How to simplify a land cover classification in QGIS

I have recently completed a land use classification using over 100 ROIs for 5 different land cover classes and it has developed what looks like a highly specific spectral signature for each class. ...
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33 views

How to access qgis module from my virtualenv

I am running an Ubuntu 14.4 and I have installed a python virtual environment. Then I pip installed several python libraries (gdal, lxml, psycopg2 etc.) Also in my system I have the module for qgis. ...
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1answer
41 views

Load a specific spatial data from a postGIS table

A single postGIS table contains multiple type of spatial data(example: Linestring,Polygon,etc.,). How to load a specific spatial data from PostGIS table into QGIS by using pyqgis?
8
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1answer
113 views

How do I Spatially Partition a whole lot of points?

I have location data of customers, with over 130 million records, spread all across the country. This is a Spatial Table in PostGIS I want to now partition the entire country into 'service areas', ...
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40 views

Local variable 'value' referenced before assignment: qgis function editor

I customized a function to edit my attribute table. It was working well but now when I used it again my qgis crash or I receive bad answer. The answer of Qgis: My code: from qgis.core import * @...
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0answers
19 views

S-52 symbology in QGIS

I can load S-57 ENC vector files in .000 format and view the data. I would like to visualise them as the S-52 standard details. These are nautical charts, some more detail here: https://en.wikipedia....
2
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1answer
52 views

Defining Datum in QGIS?

I got two shapefile of the same coordinate reference system (CGRS93_LTM), one in QGIS and the other in ArcMap. However they got different prj. files QGIS file: PROJCS["Transverse_Mercator", GEOGCS["...
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0answers
44 views

Linux based QGIS File Geodatabase access

I have looked for a "recipe" to get QGIS to read FGDB but cannot find anything. I'm fairly new to Linux and need a step by step procedure or somewhere to find the steps. I'm running QGIS 2.14.3 Essen ...
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2answers
55 views

Get the coordinates of all points having the same given latitude along a line shapefile

I have a shapefile representing a shoreline and I need to extract the coordinates of the points at a certain latitude (or longitude). Is there a tool or plugin that could do that ? Edit: to be ...
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1answer
30 views

Quick way to produce polygons to cover variable precision lat / lon points?

I'm using the Smithsonian Global Volcanism Database and have a .csv lat lon points from it. It seems they are using decimal precision on their lat lon to give a rough idea of the size of the area that ...
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1answer
38 views

How to update a text column of selected features in QGIS?

Let's say I have a bunch of postcodes. After making a selection and having the records highlighted in the attribute table, how to update all of them and give them the same category? In ArcGIS, after ...
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0answers
16 views

How to add a variable to a dataset and make sure it matches up properly?

I have two sets of data that I need to combine. One is a GIS set of points corresponding to the centroids of buildings, the other is a CDV table that has data about what these buildings are used for. ...
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3answers
33 views

Maximum altitude in polygons [closed]

I have a shapefile having 1000s of non overlapping polygons. I have got seamless layer of DEMs which cover the full extend of this polygon shapefile. I want to find out the maximum altitude value in ...
2
votes
1answer
32 views

Most efficient way to select a given layer programmatically in QGIS

this a question about code efficiency, not asking how to loop through layers. I'm getting the 'this question appears subjective...' warning but there must be a tried and tested method by someone more ...
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0answers
19 views

QGIS Show several images for a feature (Image Slider widget)

I have a layer where each feature can have more than one image. Some have 1 photo, some 5 photos, some 15. I would like to be able to show all available photos of a item in QGIS. The available Photo ...
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0answers
35 views

Is there a faster process to update one column for all features?

I have written a python script in QGIS which estimates the amount of residents for each building polygon by using census block data and building polygons (about 500 000 buildings in an area of about ...
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0answers
37 views

How to go around QGIS's same CRS restriction when doing spatial queries?

As someone who used ArcGIS pretty frequently and then moved to QGIS, I find this restriction to be pretty annoying. Normally it would be possible to convert everything to the same coordinate system ...
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0answers
33 views

Create route by hand

Is it possible to create a route placing some waypoints by hand? I mean, I don't want the program (QGIS) to link consecutive points with a simple line... I want it to link the points following the ...
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0answers
73 views

Open Layer Plugin QGIS Essen 2.14.3 defect?

I´m using QGIS Essen 2.14.3 for analysing gpx-routes. After installing the latest Version, it is not possible to install "Open-Layer-Plugin". Python says: "module" object has no attribute "wkbCurve". ...
4
votes
1answer
108 views

QGIS - Topology Checker - Feature id 0

I am running topology check "layer should have no gaps" and the result shows one error with feature id 0. Double clicking on the error shows a large Dodecagon that is not part of my layer. How can I ...
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2answers
71 views

Angle at intersection point from two Lines

I would like to find the angle of two lines at their intersection point. In my opinion it is the azimuth I'm looking for, right? So I'm using Python with shapely for finding the intersection and ...
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0answers
28 views

Enable LSCV kernel density estimation for Animove in QGIS?

I am currently studying primate home range behaviour and I want to create a kernel density utilization distribution based on the least-squares cross validation bandwidth parameter (LSCV), as some GPS-...
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0answers
24 views

QGIS image classification to use maximum likelihood, minimum distance or spectral angle algorithm?

This should be a straight forward one... I have selected over 100 ROIs from ground truthed data. I am using LANDSAT 8 imagery. I want to now perform the classification (which I guess is a supervised ...
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0answers
16 views

Load a pre-defined legend into MapCompser programtically with python

Is there a possibility to load a predefined lendend into the MapCompser with python? I want to use instead of createLegend(...) (..see below) something like def loadLegend(file): .... def ...
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0answers
21 views

Data Point Displays on Map, But Not in Attribute Table

I am doing a project mapping out the stormwater drainage systems in my town. This is only the second point it has happened to, but it will display in the correct spot on my map, but not show up in the ...
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3answers
51 views

QGIS Dissolve: Limit output file format to .shp only

I'm new to QGIS and recently I've been trying to dissolve two large shapefiles together after they have been merged. It's taking an awful lot of time for each operation and I'm trying to speed up the ...
1
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1answer
44 views

PyQgis create labels

I am creating a QgsVectorLayer in a plugin and loading it into the map. I would like to set the labelling parameters while I'm doing that. I've followed several examples found here and here, but my ...
1
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1answer
45 views

How to implement layer.setEditType for custom widgets in QGIS?

How could I use layer.setEditType() method in QGIS for a custom form widget? Cusom form elements are well explained by Matthias Kuhn here. I was able to change the existing default widget types. For ...
3
votes
2answers
132 views

Bulk file convertor QGIS plugin/program

Similar questions have been asked but without I think non "script" solutions Is there a easier to use for non technical users for QGIS plugin/program to bulk export files? Say shp files to .kml files?...
2
votes
1answer
41 views

QGIS Oracle-Spatial-GeoRaster-Plugin not working

I am having trouble with Oracle-Spatial-GeoRaster-Plugin in QGIS (running on Windows 7 Professional N 64bit). The connection to my database on an external Oracle-Server obviously works as it shows the ...
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0answers
19 views

QGIS join attribute data to dxf file using EntityHandle as key field

I would like to joint attribute data (csv table or slt.) to a drawing (dxf file) imported to QGIS. Such imported data have an attribute EntityHandle which seem to me like an AutoCAD specific 'id'. I'...
3
votes
2answers
51 views

Export map composer extent to a layer

In QGIS, I am trying to use the Create Grid for Indexing plugin more efficiently. I would like to know if it is possible to export a map composer extent to a layer (a layer with one rectangle polygon) ...
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1answer
38 views

Geotag shape files

I have several shapefiles that are supposed to be in epgs:4326 but the projection is correct only relative to each other, not absolutely. Is there a way I can geotag shapefiles without having a ...
2
votes
1answer
44 views

QGIS 2.14.3. positioning gap between open layers layer and aerial image

When I add aerial images from a recent survey (delivered in EPSG:31468, DHDN_3_Degree_Gauss_Zone_4) to an empty project together with an openlayers osm layer I'm facing a strange positioning issue. I ...
2
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0answers
35 views

How to keep basemap high res detail when printing large resolution in QGIS?

I need to print a map with a0 resolution and I need it zoomed over a large area. Problem when zooming out is that the basemap also gets zoomed out and loses labels and important details. Basemap is ...
2
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1answer
38 views

Rendering based on layer overlap qgis?

I'm a little new to this, is there a way to have features on a layer render only if they overlap with features on another layer? I have roads of a city, and different areas in the city, and I'd like ...
1
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1answer
23 views

Change project CRS = discard GCPs?

[Using QGIS 2.12 Lyon on Mac with OS X 10.10.5] I am struggling to georeference some old hydrographic survey maps that are in the form of TIFF files (.tif). If I open the georeferencer tool and set ...
0
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0answers
46 views

Read a vector layer from a Postgres/PostGIS database via a SQL query with QGIS and ogr in a python script

I have a treatment table for different aggregation stategies on a geospatial table in a PostgresSQL/PostGIS database. The aggregation strategies addressing temporal and species specific pre-selections ...
2
votes
2answers
49 views

qgis raster palette won't appear

I am trying to style a new single-band raster with a platted style, but when I choose the ‘platted’ no colors or values appear, and I can’t find a way to add them. QGIS Essen, Win 7.
2
votes
2answers
197 views

openlayer-plugin error after installing update

after installing an update for the openlayer-plugin today, this plugin does not work any longer. Reinstalling did not function neither with QGIS 2.12.0-Lyon nor with QGIS 2.14.1 ESSEN. Following error ...
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2answers
36 views

Integrating R in QGIS with Mac OS El Captain: missing dependencies

I have a Mac OS (El Captain) and I'm trying to run R scripts within QGIS 2.14. When I open a script (like one from the online list) I receive the error message: This algorithm cannot be run :-( ...
4
votes
2answers
80 views

How to organise complex styling rules in QGIS?

For example, my "roads" vector layer has the following attributes: road type: primary, secondary, local, track, or path surface: sealed, or unsealed segment type: road, bridge, tunnel, floodway, ...
2
votes
1answer
54 views

pyQGIS merging shapefiles

I've been searching the internet for a while now trying to look for a way to merge all the shape files from a directory (a folder) into a single shape file. I found many solutions but none of them ...
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0answers
57 views

Where does the snapshot command take its pixel samples from?

I'm using the snapshot command in QGIS with a horizontal extent from 0 units to 24 units to create an image with a horizontal resolution of 4 pixels. Are the output pixels located at 3,9,15,21 (...
1
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1answer
46 views

How to get neighbor list and export

I have a shapefile from the Census Bureau on Zip Code Tabulation Areas (http://www.census.gov/cgi-bin/geo/shapefiles/index.php). I wanted to get, for each zip code, the list of neighboring zip codes. ...
2
votes
1answer
60 views

Using 'ogr2ogr' algorithm in QGIS to transform SHP to GPX

So I am trying to convert a LineString shapefile into GPX using the 'gdalogr:ogr2ogr' algorithm in a QGIS python plugin. The problem is that I alway get routes instead of tracks, even if I specify ...
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2answers
47 views

QGIS autoupdate attributes

How to change attributes value when i move(change position) point? I don't found some information about this. Sorry for my english.
3
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2answers
172 views

Generating an image representing inland surface water using QGis and OSM data

I'm trying to generate a raster image representing surface water for a given bounding box. I'm using OpenStreetMaps data as my input for water bodies, and I'm using QGis on Ubuntu to process this data....
3
votes
0answers
45 views

Python QGIS crashes within categorized renderer setup

I'm hassling around with QGIS renderer definitions in python with QGIS 2.8 at debian wheezy. At least I want simply build step by step a categorized renderer to fill a polygon. The script crashes, ...