Questions tagged [qgis-2]

Version 2.x of QGIS (previously Quantum GIS)

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4
votes
2answers
15k views

How to snap lines to nearest point?

Is there an easy way to snap lines to nearest point of either a line or a polygon? I don't see any snapping options for line layers as suggested on How to merge lines with slightly different endpoints ...
4
votes
0answers
61 views

Is there a way to customize the Options dialog in QGIS 2.14.6?

I'm creating a deployment package to update QGIS from V2.8 (wien) to V2.14 (essen (LTR)). In QGIS 2.14 there is a new "Advanced" section under "Settings > Options", see screenshot: Can this menu ...
3
votes
2answers
2k views

QGIS 2.0 Plugins missing [duplicate]

At the risk of a series of down votes but I have just installed QGIS 2.0 after using 1.7.4 and 1.8 previous. It looks great but there are a lot of plugins missing. I understand from the install that ...
3
votes
4answers
187 views

Selecting features with same geometry in one shapefile

@TeddyTedTed's answer is nice, however, I am looking for something more efficient. I am working on a public transport network in one shapefile (polyline type) in QGIS 2.18. Certain bus routes ...
3
votes
1answer
7k views

Intersection error QGIS - invalid geometries that are actually valid

I'm trying to intersect two vector layers (having the same CRS EPSG:4326 WGS 84, in QGIS 2.18.10) but I get this error in the log: Input layer A contains invalid geometries (feature 52). Unable to ...
3
votes
0answers
980 views

QGIS 2.14 fails to install on Ubuntu 14.04

My previously working installation of QGIS 2.14 on Ubuntu 14.04 suddenly failed to start QGIS. I have been trying to reinstall QGIS without success. I have tried several ways to completely uninstall ...
3
votes
2answers
431 views

QGIS Editing: move - both - nodes after Cut has been performed

I just ran into unexpected behavior while editing a polygon shapefile in QGIS 2.8.2. Scenario: A polygon: Then I cut that polygon into two seperate poygons: Then I use the Node Tool to move a ...
3
votes
1answer
1k views

GRASS plugin missing from QGIS 2.14.3 Essen in Ubuntu 14.04

I had installed QGIS 2.14.0 (or .1 not sure) and I did some work with the GRASS plugin a couple of months ago, so it was there. I upgraded a couple of weeks ago to QGIS 2.14.3 and I was planning in ...
3
votes
3answers
2k views

Why is SAGA from the Processing Plugin not recognised?

Similar to SAGA algorithms don't work in QGIS 2.8 except that SAGA does not appear at all in the Processing Toolbox: As a check, I used the Python Console with the following code to see if any ...
3
votes
2answers
5k views

Changing precision on a column in the attribute table without losing data?

I have data in an Excel file that I want to join with a shapefile in my project. The Excel file contains values like volumes. The Excel file and the shapefile I want to join it with both contain the ...
3
votes
1answer
259 views

QGIS 2.6 summarizing area (m²) for current atributes

If I have a code for each polygon and I have counted the area in m² for each of them (all this information is in single columns). How can I summarize these areas by codes (for example summarize all ...
3
votes
1answer
1k views

QGIS 2.0.1 Runtime error and crash at Add Delimited Text Layer plugin

I just installed Dufour on my Windows 7 Lenovo ThinkCentre desktop. When I open 2.0.1 I get this error window: And when I try to add the 'Add Delimited Text Layer' plugin I get this message: When I ...
3
votes
1answer
194 views

Piping output of one processing algorithm as input into another algorithm in QGIS Processing script?

I created a processing script in QGIS 2.18 that connects two processing algorithms (first clip and than dissolve). The output vector from the clip is supposed to be an input into the dissolve. The ...
2
votes
2answers
84 views

Deleting vector lines beyond image extents using QGIS?

I am using QGIS 2.2 I have one vector line layer (roads) that stretches beyond my base image (see below). I wish to have the roads "clipped/trimmed or deleted" right at the edge of the image's ...
2
votes
1answer
946 views

PostgreSQL default values in QGIS 2.8.1

I have a problem with default values the are set in a PostgreSQL table. When I work on them in QGIS 2.8.1 and I save the layer, the default values were not computed, so the constraints block me. With ...
2
votes
2answers
735 views

How to fix corrupted QGIS project file that causes Windows to freeze?

I'm running QGIS 2.14.9 on Windows 7 SP1. I have a project that contains PostGIS layers from a remote server, as well as some (local) shapefiles that I've been doing some development on in the Python ...
2
votes
1answer
415 views

Shattered, rough WMTS image in QGIS 2.18.12

After updating QGIS i found that wmts layers are being rendered in way that makes them useless. It look's like tiles are downloaded in greater resolution and then scaled down what makes them rough and ...
2
votes
2answers
2k views

Is there a way to quickly paste multiple columns of data into an attribute table in QGIS?

So I have a shapefile with 133 rows of data, and I want to add 4 extra fields to it. My problem is that after I have created the new fields in the attribute table, I have no way to quickly paste the ...
1
vote
1answer
551 views

SHP file Left / Right Label Alignment issue in QGIS 2.0.1-Dufour

cld anyone let me know how it works to get the desired label placement for the opened SHP file into QGIS 2.0.1- Dufo
1
vote
2answers
329 views

QGIS 2.10.1 (64bit) rotation field setting missing

I cannot find the the rotation field setting under the properties-layer settings-advanced (for styles) menu in the new release of QGIS (2.10.1 64bit). The only setting what is available there is the "...
1
vote
1answer
766 views

Connecting vector label size with map-units?

I have a working application of labels to a point array - but the size of the text is not relative to the map scale. This decreases the readability of labels when panning and zooming. To resolve~ ...
1
vote
0answers
372 views

Viewshed analysis plugin on QGIS keeps resulting in errors

I've been trying to test the Viewshed analysis plugin on QGIS 2.10, but it keeps giving back error messages. I've tried to reduce the radius area and have also reprojected both my DEM and my point ...
1
vote
1answer
809 views

Projecting vector data in QGIS?

I'm running QGIS 2.2 on Ubuntu 14.04. Trying to project data gives me a hard time right now. The last time I did that was in 2.0 and I basically changed the projection by saving the data as a new ...
1
vote
1answer
640 views

QGIS Buffer Not Recognizing All Features in Layer

I'm completing online course GST 101 for QGIS (my version is 2.18.3) and I'm stuck on the Buffer tool. All of my layers are set to CRS "NAD83(HARN)/New Mexico Central (ftUS) (EPSG:2903)" as ...
1
vote
1answer
981 views

QGIS: SQL query within python console to sum a column based on values of other two columns

We have 100's of shapefiles for which we have to generate excel reports based on few (combination of) parameters in the attribute table. I am using SQL query to achieve this and when i run the query ...
1
vote
1answer
2k views

QGIS Error when clipping a raster with a shape layer

I am trying to clip a .tif file using the extent of a polygon (.shp). I am using the conventional Raster/Extraction/Clipper tool in QGIS 2.18.10. After choosing the appropriate settings, I get the ...
0
votes
1answer
2k views

QGIS 2.0 - can't select items in Print Composer

I am having an issue where I can create a print Layout in Print Composer, but once I have clicked away from an item (like map, legend, arrow, etc) I cannot select it again.
0
votes
1answer
607 views

Qgis map composer shows a huge red cross

I can show this best by a picture: This cross also shows when I export it as raster or pdf. What is it and how can I get rid of it? I am using Qgis 2.4 and the map was done with the help of the ...
0
votes
2answers
685 views

GRASS algorithm r.los does not produce raster

After running the r.los algorithm through QGIS 2.0, I'm getting a 'Problem loading output layers' box which gives the following message: Oooops! The following output layers could not be open Output ...
0
votes
1answer
1k views

get wkt from geometry in lat lon format

Using the plane geometry editor plugin in qgis 2.0, WKT representation of a feature is shown. The result is in the lon1 lat1,lon2 lat2 format. e.g. POLYGON((85.43523762804622379 27.69592296476042037,...
8
votes
1answer
8k views

How to find the watershed area for each point in the river network using DEM?

Update#1: Thanks, Micha, I have followed your instruction and successfully use the modules in GRASS. I use r.watershed to get the basin raster and the drainage line: and I use r.water.outlet to get ...
11
votes
3answers
2k views

Getting points-touching-a-line attributes back to lines layer using QGIS?

I'm using QGIS 2.14.4-Essen. I have two layers: points.shp that contains points with a YEAR column lines.shp that contains lines that exactly connect the points from points.shp I would like to get ...
6
votes
2answers
5k views

Activating layer by its name in PyQGIS?

I'm writing a script that requires the attributes of different layers to work, and I would like to know how to call a layer that is not the currently active one and get its features. For example, I ...
8
votes
4answers
13k views

Resizing the map item in QGIS print composer without changing scale?

Is it possible to lock the scale in the QGIS 2.0.1 print composer? Every time I resize the map, the scale is adjusted. This makes trying out different map layouts really annoying.
7
votes
1answer
2k views

How to fix polygon with ring self intersection in QGIS?

When I polygonize a raster, I very often have 'pixels' holes/interior ring that touche exterior ring. Example : POLYGON((5 0, 10 0, 10 10, 0 10, 0 0, 5 0, 3 3, 5 6, 7 3, 5 0)) It's defined as an ...
4
votes
0answers
486 views

Computing the slope of a road using DEM

I work with QGIS 2.14 and I want to create a map of road network showing the slope of each road with at least this scale: <3%; 3-5%; 5-7%; 7-9%; >9%. I already have a vector layer of roads and the ...
3
votes
1answer
283 views

Upright/Horizontal labels when labeling circular polygons at perimeter?

I have several polygons (circles) I want to label with their ID number. The label should be outside the circles so I use the positioning options "Use perimeter" and the tickbox "Next to the line (or ...
8
votes
1answer
4k views

What's the QGIS Legend Format Syntax to label percentage values?

I asked a question about formatting legend text a while back and I'm happy to see the issue has been solved in QGIS 2.6: How to remove trailing zeros from QGIS Graduated Style Class labels? But I'm ...
7
votes
1answer
2k views

Displaying azimuth of line in QGIS? [closed]

I have drawn a series of straight lines on a map joining different locations. The lines have a single vertex at each end. I am using the Ordnance Survey of Great Britain 1936 projection. I now ...
5
votes
2answers
2k views

How to enable UI Theme Support in QGIS 2.12?

According to the 2.12 Changelog QGIS now ships with a light and a dark UI Theme. A longer description of the UI themes can be found at Nathan Woodrows blog on QGIS UI themes. However, when I install ...
5
votes
2answers
2k views

Key for a Heat Map

I have a question about heat maps and the correct way to describe the results. I have a dataset of small historic territorial units which vary greatly in size in different parts of a country. I want ...
5
votes
2answers
2k views

Best Landsat-5 TM band combination for detecting fire scars [closed]

I am looking for the best band combination with Landsat 5 imagery to detect fire scars.
4
votes
0answers
1k views

How do I export a 16-bit image from QGIS?

Could someone explain how to export from QGIS a 16bit image. I have imported data and coloured it as I want, but need to export it as a 16bit image, as 8bit is giving a terracing effect.I believe I ...
3
votes
2answers
1k views

Project file read error: Unexpected end of file at line 9957 column 1

On reading the answers from a similar question earlier i still cannot retrieve my project. I last used this project in June and obviously something went wrong when saving or creating the new layer ...
3
votes
1answer
459 views

How can I use relative paths in print composer for images?

I'm sharing an entire map project with a client so they can eventually print off an atlas. I've managed to get all the layers and icons to work correctly with relative paths, but the atlas contains ...
1
vote
1answer
2k views

Set Relative Hyperlink to open windows explorer using Actions in QGIS

I am wondering how to solve this problem I am having. I am trying to make an action in QGIS when I click on my feature, windows explorer will display the folder for that feature. I have the folder ...
19
votes
0answers
201 views

Output formats for QGIS Heatmap plugin not appearing in drop-drown in Ubuntu [duplicate]

I've been trying to use the heatmap plugin on QGIS (2.8.2) on Ubuntu(14.04) but the drop down for the output formats doesn't get populated. Selecting the drop-down allows me to press OK on the ...
9
votes
2answers
1k views

Starting QGIS with virtualenv Python?

is there any means of telling QGIS to use a different Python installation than the default, system-wide one? E.g. use some virtualenv Python /myvirtualenv/bin/python instead of /usr/bin/python? ...
9
votes
1answer
40k views

How to put North Arrow and Scale on map in COMPOSER in QGIS 2.2.0

I am new to QGIS and the questions asked and answered here about the North Arrow do not seem to help me solve my problem below. In the main mapping pane of QGIS 2.2.0 Valmiera, I can add the scale ...
8
votes
1answer
211 views

The longest straight line (L) within a polygon and the longest perpendicular line (T) to L

I'm mapping elongated glaciological features within QGIS 2.18.22 and I need to measure the longest straight line (L) and the longest perpendicular line (T) to L (as illustrated in the picture) within ...