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

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2
votes
2answers
112 views

How to label one point bigger than all others in a layer?

I have a point dataset in one layer. I labelled all points but I would like to label one point larger size than other point labels. How can I do it? Merzifon and Bahçecik are in the same point ...
0
votes
1answer
52 views

QGIS loop/iterator with python in function editor (field calculator)

I am trying to create a loop to rename the fields of my attribute table. The fields should start at 1 and increment by one until the end of the table (e.g. 1,2,3,4,5,...,n) my code on the python ...
4
votes
2answers
68 views

How to merge and dissolve adjacent polygons and sum up their attributes in QGIS?

I have many polygons that are adjacent to each other, and others overlap slightly. I need to merge them and sum up their attribute (Area per class). I attach an image of my problem (Screenshot of my ...
4
votes
0answers
53 views

Calculating angle using three WGS 84 points

I am looking for a way to calculate an angle between two points at a specific third point. My coordinate system is WGS 84. I can measure the angle with QGIS clicken on those three points, but I want ...
0
votes
0answers
27 views

GDB for offline viewer

I'm newbie for geographic information systems, I want to build Mapping offline. I have data with GDB file, before i use map source to open that file and we can view online in google earth, but now i ...
2
votes
0answers
24 views

Problem with adding non spatial view from MSSQL to QGIS

I have QGIS 2.12.3 app installed on one server (servername1) and MSSQL server database installed on servername2. The database is password protected and I have made connection successfully using QGIS ...
3
votes
1answer
34 views

Spatial join of raster data in QGIS

How do I perform spatial join of raster data in QGIS? I have raster soil data (tiff), I'd like to join this to an attribute table in excel? I'm not able to view the attribute table either? Is this ...
2
votes
0answers
18 views

How to create concave polygon with constraint angles in qgis?

I'm having point data. By using that I wanna create concave polygon with some constraint angles (i.e., >45 and <225 degree). Is it possible to do in QGIS?
0
votes
0answers
17 views

Unable to load Arc Binary Grids in QGIS

I have a single band 32-bit integer Arc Binary Grid. Using QGIS 2.12.3, when I try to add this Grid, it is listed in the table of contents, but nothing shows in the map window. To add the Grid, I ...
3
votes
1answer
32 views

Distance matrix tool, how to include distances at 0 metres?

I have used the Vector -> Analysis Tools -> Distance matrix to merge two datasets by the closest points. But in my output csv file, the points that match exactly, or that has 0 metres between them ...
1
vote
2answers
21 views

One CSV with field that delineates CRS for QGIS?

I have a CSV with points with X,y coordinates. One of the fields is "Horizontal Datum," which says what the projection is. Here is a sample of the sheet: QGIS lets me import this csv file, but when ...
2
votes
0answers
50 views

Why azimuth result is wrong for this pyqgis code?

In this code I want to obtain azimuth from a single point to each pixel center, but when run it, in raster created azimuth result for each pixel is wrong, what is correct code? from osgeo import ...
3
votes
0answers
28 views

How to assign polygon attributes to grid cells using centroids in QGIS?

I am relatively new usign QGIS but have realized it is a great tool. Unfortunately I can´t figure out the following yet. I have two polygon shapefiles, one is a grid I have created using QGIS ...
1
vote
0answers
19 views

Preparing CliMond data for Maxent

I had been working with BioClim data and that was working in Maxent. I could clip files and realign them etc. Now I have some data from CliMond which is in two formats: Either as text files ...
3
votes
0answers
27 views

zonal statistics / join with two vector layers [duplicate]

I have a shapefile containing three polygons of river basins with different values. I want to know the average values per country. The country thus contains three river basins. When I use join in ...
1
vote
0answers
19 views

Georeferencing an NDVI (JPEG) image in QGIS

I am struggling to georeference a NDVI image. The image is a JPEG, how would I go about this? I am using QGIS
3
votes
1answer
67 views

python script for opening webpage directly in qgis

I have a shapefile with points reffering to a webpage with a photograph. Untill now I define an action to open the corresponding webpage in firefox. Eg. I have to share my project. Because I don't ...
2
votes
0answers
83 views

QGIS: Snapshot command not producing high-res image

I'm trying to export an image of my project with a size of several hundred megapixels (32768x16384) via the snapshot command and all I get is an output file with 0 KB and no error message. I can ...
1
vote
1answer
25 views

QGIS: Distance Matrix tool omitting some points in output table. (qGIS 2.10.1-Pisa)

I have used the Analysis Tools -> Distance matrix to merge two datasets by the closest points. But in my output csv file, some of my points are left out. In the original datasets, none of these points ...
1
vote
1answer
39 views

How can I prevent the scale bar in print composer from bunching up in QGIS?

I'm creating a series of maps in print composer from the same basemap (from the quickmapservices plugin) in QGIS 2.12.2. Sometimes this works, though it only allows the scale to be in metres, feet or ...
7
votes
1answer
126 views

Join by attribute / spatialite with SQL / left outer join in QGIS

I have a layer with polygons (let's call it "woods") that is intersected by "n" line-objects ("roads"). Every road has an unique attribute roadid. I need to add ALL the roadid's (not only the first ...
3
votes
1answer
102 views

Update area column after changes in QGIS

I'am using QGIS and POSTGIS, for example to automatically calculate the area of a new created polygon. I do that with following code: CREATE OR REPLACE FUNCTION calc_area() RETURNS trigger AS $BODY$ ...
2
votes
2answers
53 views

Generate multiple contour lines at specific elevations

Can anyone suggest a method by which I can produce several user-defined contour lines (from a DEM) within a single shapefile using QGIS/GRASS (2.12.x) and its plugins. Each approach I have tried has ...
1
vote
0answers
41 views

Cannot import name QtTest running unittests for QGIS plugin

I have the following imports in my unittest code: from PyQt4.QtCore import * from PyQt4.QtGui import * from PyQt4 import QtCore, QtGui, QtTest When I run my unit test from the command line I get ...
1
vote
1answer
32 views

print polygon from “the_geom” field in postGIS database

I have a postGIS database with plots and features (owner, area, address, etc) and I would like to print any selection of that like a card. I mean I would like to show each record in a page with the ...
1
vote
0answers
92 views

QGIS OpenLayers not working

I am an extreme neophyte with QGIS, so I maybe doing this all wrong. I have loaded the OpenLayers plugin as described in several online posts (and youtube video), and it is shown as listed in my ...
1
vote
0answers
13 views

Mosaic with LISS-III RESOURCESAT-1 images

I'm having problems with dark edges in normal or virtual catalog (.vrt) with LISIII LISS-III RESOURCESAT-1 mosaic. If I put no data value 0 in properties, change border by white (see figure) and I ...
3
votes
1answer
42 views

Looking for spatial analyst tool between raster and vector layers in QGIS

I'm aiming to do a similarity analysis between a raster layer and a vector layer. The raster layer is a 5-class ice map and the vector layer (points) contains ice jam events data. The goal here is to ...
2
votes
0answers
34 views

Finding and using mean and standard deviation value in field calculator

I am creating a field for a z-score of a particular attribute. This requires calculating the mean and the standard deviation for the attribute across all features. I've been using the statistics ...
1
vote
0answers
40 views

Viewshed Analysis for total beginner [closed]

I am totally new to doing this using QGIS. Can anyone help me to produce the following, which I believe is commonly known as a ZTV analysis. I am running Wein and have the Viewshed Analysis plugin ...
3
votes
1answer
46 views

Automating Interpolation in QGIS

I have a project in QGIS which involves interpolating several different variables on several different maps, then using the raster calculator to multiply some of the resulting interpolations together. ...
3
votes
1answer
32 views

How to replace a directory using QGIS Field calculator?

I have a column called Hotlink full of incorrect directories and I need to edit them. They currently read C:/ABCD/filename.pdf and I want them to read C:/Maps/ABCD/ABCD/filename.pdf The script I'm ...
7
votes
1answer
139 views

How to speed up QGIS project opening with large point datasets?

I recently loaded a big point set (in terms of memory usage) in the QGIS project i'm working on. This layer is necessary for the project but it is not used often. Most of the time is turned off. The ...
3
votes
0answers
24 views

r.sun from QGIS toolbox doesn't give realistic value about the hours of insolation

I have a problem with the GRASS module r.sun when I run it in QGIS. I would calculate the hours of insolation in a specific site during a specific day. When I ran the algorithm "r.sun" from GRASS, it ...
1
vote
1answer
21 views

Basic instructions for loading OS Terrain 50 data

Are there any basic instructions for using the OS Terrain data available online? I do not have an issue extracting - it is all sat in a folder ready to go. What I cannot work out how to do is to ...
0
votes
0answers
25 views

Spatial weight matrix QGIS - export to stata

I'm looking to estimate a spatial panel model in STATA, however, I'm running into difficulties creating a spatial weight matrix. For note my N=66 while my T=25. I'm a novice when it comes to ...
2
votes
0answers
19 views

Grid buffer in QGIS

I do have a raster file (grid) which I have processed before with the SAGA kriging tool. Is it possible to buffer this raster file a little bit (expanding the interpolated result) of 1 or 2 grids? I ...
3
votes
0answers
31 views

How to calculate average value of a raster, that is clipped by multiple polygons?

I am using QGIS 2.12.0. I have a raster of coherence value (SAR interferometry) and a land use shape. I wish to calculate mean coherence value for those areas with a specific land use. I split land ...
3
votes
3answers
47 views

Patching a large number of Landsat 8 scenes together

I need to extract land cover information (vegetation, water bodies, etc.) using Landsat 8 scenes. I have to extract the information on a country scale which means that I have about 15 scenes ...
1
vote
1answer
39 views

QGIS Zonal Stats Plugin - Python Console - compute one specific statistic

I think this is more of a syntax problem that I have here. But I am absolutely not able to figure it out. On a different Linux machine I got the following working: zoneStat = QgsZonalStatistics ...
1
vote
0answers
10 views

pinchZoom with qgis 2.82 and qt

I am working with qgis 2.8.2 c++ api and qt4.8.5 in my project i had to implement the pinchzoom because i use a 27" touch screen i am looking for information on how to use the qgis lib with the qt ...
2
votes
2answers
52 views

Copy geometry from one layer onto attributes of another?

I have two polygon layers, A and B, that have the same features but totally different attributes. I want to use the attributes from layer A, but I want them to have the more accurate geometry from ...
0
votes
1answer
54 views

QGIS - what is the core database system? [closed]

What is the core database system used by QGIS? When you launch an existing project that has multiple .shp files (with associated .dbf tables), is the core db system used to convert that data to its ...
1
vote
0answers
30 views

Why is GDAL/QGIS creating Geospatial PDF's with erroneous spatial data?

I have a GeoTiff that I wish to convert into a geospatial PDF for use in Avenza. I attempted to use gdal_translate, and also used the QGIS's Raster->Conversion->Translate which apparently just builds ...
1
vote
2answers
41 views

Importing OSM data into PostGIS and display into QGIS

I am new to all the GIS thing but I need to set up a full GIS infrastructure for a project. I have installed a Postgres server with PostGIS. That is on ancient hardware for now, 32bits processor with ...
4
votes
2answers
57 views

performance problem with PyQGIS: manipulating attributes

I have selected a vector layer with attributes slope and area. I want to combine all the features with slope 0 to 5, 5 to 10, ... , 85 to 90. The original features are to be discarded, and new ...
3
votes
1answer
69 views

QGIS Field Calculator functions

Using QGIS 2.12.3, within the Field Calculator "Geometry" section, there are certain functions, such as "area", that also have a corresponding term beginning with a dollar sign, i.e. "$area". I don't ...
3
votes
2answers
62 views

QGIS: Updating labels based on delimited text layer

I have a csv file that I am joining to a layer, then creating labels based on the joined layer. When creating the delimited text layer, I include the option to watch the layer. At the time of ...
4
votes
0answers
26 views

QGIS Atlas: Filter maps based on attributes (more than one)?

I have a series of maps with the same geographic boundaries but with different set of points (from the same layer). I would like to create an Atlas where the change is based on the attributes. A ...
1
vote
1answer
31 views

QGIS symbology: where are simple markers located in the system?

I would like to know, where are simple svg-markers (for example the one that is defined as "regular_star" in .qml file) are physically located in the system? I searched the system and looked inside ...