Questions tagged [qgis-2]

Version 2.x of QGIS (previously Quantum GIS)

346 questions with no upvoted or accepted answers
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11
votes
0answers
342 views

Multithreaded DB connection for QGIS plugin

I am using QGIS 2.18.21 and PostgreSQL 9.6. on a Windows 8 machine. I am trying to do processing of a certain database task in the background, and I want the user to be able to continue to work in ...
6
votes
1answer
959 views

Postgis sequence in QGIS not working

I have a Multipolygon-Layer stored in a PostgreSQL/PostGIS database. The primary key field 'gid' is SERIAL. When trying to add a new polygon in QGIS (LYON 2.12.1 on OSX El Capitan), the attributes ...
5
votes
0answers
209 views

Speeding up execution of PyQGIS algorithms

I don't understand why if I do "manually" some algorithms I get results much faster than when I insert the same in a PyQGIS code (with the same input). This happens, for example, with the ...
5
votes
0answers
839 views

Creating text buffer in legend QGIS 2.18?

I work with this polygon layer and this is my map composer: I used the labels with Text Buffer (yellow and red), and I try to find how I can make the same text buffer in the layer name in the legend. ...
5
votes
0answers
660 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 ...
5
votes
0answers
5k views

K-Means clustering in QGIS (Attribute based clustering)

In the 2.18.4 and 2.18.5 version of QGIS K-means clustering was moved to a plugin called 'Attribute based clustering'. However, I am working with a virtual raster dataset (vrt.) and the current ...
5
votes
0answers
8k views

Is there an "undo" button in QGIS 2.18?

In ArcGIS there an option of "undo" button I seek this option in order to return my steps if it necessary. I try to find such option in the menu and didn't found any like it. What can I do?
5
votes
0answers
568 views

QGIS Align Rasters how to retain pixel values?

I am attempting to align and then merge a number of rasters of the same resolution and extent, but where the pixels are slightly misaligned (creating small gaps when merged). This works fine using the ...
5
votes
0answers
855 views

Programmatically removing layer from QGIS composer legend without removing it from map canvas?

I am working on a QGIS Python plugin which includes automated map production. I use a series of map templates, each of which has a main map, an overview map (with a layer set different to the main ...
4
votes
0answers
36 views

How to eradicate excess lines in a singly recorded polygonal line (road) network? QGIS 2.8

I'm a beginner in GIS software. I'm trying to create a road network shapefile within the reserve I work at. To do this, I've driven each and every road inside the property with my GPS app set to ...
4
votes
0answers
62 views

Topology checker - whole polygon highlighted rather than polygon segment

When I check for overlaps, topology checker is only identifying errors at the polygon level but not the polygon segment where the errors exist (the whole polygon is highlighted in blue). I believe ...
4
votes
0answers
1k views

Merging asc files in QGIS?

I am trying to merge 8 .asc files using merge option in QGIS 2.4 but when I do that it makes like contour of the file when I want to merge the files together. .ASC Files: Result after merging:
4
votes
0answers
412 views

QGIS (Python) crashing when trying to iterate through layers in a thread

Version: 2.18, and I cannot upgrade to 3. I am adapting a script I found elsewhere on stackexchange which is supposed to indefinitely refresh all layers in the TOC at one-second intervals. This is ...
4
votes
1answer
401 views

Getting error when trying to use IPyConsole Plugin in QGIS 2.18.16

I am trying to use the IPyConsole Plugin and the error I receive tells me I have to install IPython 3.1.0 or Jupyter 1.0.0. So I followed the link they gave me and installed Anaconda 2.17 and then 3 ...
4
votes
0answers
251 views

Get signal on delete group on QGIS 2.18.16

I tried : QgsProject.instance().layerTreeRoot().willRemoveChildren.connect(self.onWillRemoveChildren) It works if I delete a group within in the root node. But if I delete a layer within a group ...
4
votes
0answers
190 views

QGIS 2.18.14 vector Clip analysis producing erroneous result

I am trying to perform a vector clip analysis (vector-->geoprocessing tools pull-down menu) using two complicated vector layers and am getting erroneous results. The clip 'Input layer' is shown here: ...
4
votes
0answers
229 views

QGIS Custom Qt Widgets on OSX

When I install QGIS on windows I get a bunch of custom widgets in Qt Designer On OSX I can't figure out how to get those same widgets to appear in Qt Designer. I have set my environment variables ...
4
votes
0answers
64 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 ...
4
votes
0answers
839 views

Qgis 2.8.9-Wien Attribute table Update Fields Error

I can't update fields in the Attribute table. I get an error when I select Update All and Update Selected: An error occurred while evaluating the calculation string: No root node! Parsing failed? ...
4
votes
0answers
354 views

Can I change the precedence when combining "Control feature rendering order" with QGIS symbol levels?

I'm trying to produce a QGIS map style / symbology for processed openstreetmap data. For roads, I'd like to mimic how the OpenStreetMap web tile map "Standard" rendering style (produced with mapnik ...
4
votes
0answers
306 views

Specify position of curved label in QGIS?

From this answer in 2012 underdark stated: BUT you won't be able to have curved labels anymore if you move/rotate the labels manually, as far as I know. It's now 2016, and I noticed that I can ...
4
votes
0answers
833 views

Zonal Statistics tool not working with QGIS?

I wanted to try the QGIS 2.14 zonal statistic tool but it doesn't work.The system says: not a sequence See log for more details The SAGA Zonal Statistic tool works fine. It also doesn't work with ...
4
votes
0answers
383 views

Rule-based labeling and the Data defined placement options are not working together (QGIS 2.12, 2.14)

After setting "Rule-based labeling" to my layer (new feature since QGIS 2.12), my data defined labeling is not working any more (see labeling tools on the right side): Going back to "Show labels for ...
4
votes
0answers
261 views

SAGA Tool in QGIS Error: Load table: Proj.4-WKT Dictionary... failed

I have some problems with running SAGA tools in QGIS. I've downloaded and installed the software via the OSGeo4W Installer. It downloaded QGIS 2.12 and Saga 2.1.2. I wanted to use the Tool "Shapes To ...
4
votes
0answers
212 views

How can I see the 'Custom Options' metadata following Save As in QGIS?

In QGIS 2.10 Pisa, I've right-clicked a layer in the TOC and used Saved As ... to save a shapefile with a new name. During this process, I used the Custom Options (Data Source and Layer) to include ...
4
votes
0answers
529 views

Different scale of basemap after exporting to PDF/Image

After creating and exporting my map to pdf/tif obviously there are different scales of the basemap in the exported file compared to the map I created in the printcomposer. See pictures... I am using ...
4
votes
0answers
397 views

PyQGIS: standard and advanced linear referencing possibilities

I'm aware of the existence of the following QGIS plugins: QChainage Event layer linear referencing LRS Although, all of these tools offer some linear referencing capabilities, I find that they lack ...
4
votes
0answers
926 views

How to export data from sql server into shapefile in the decimal format in QGIS 2.4?

The last couple of days, I have been working on exporting data from SQL to a shapefile in QGIS 2.4. While converting into a shapefile, the data type changes automatically from Float to Integer in the ...
4
votes
0answers
1k views

How can I label the pie charts in QGIS so the labels are written under the diagrams?

How can I label the pie charts in QGIS so the labels are written under the diagrams? My pie-charts are representing localities: such as villages, towns, cities. So, I want that their names appear ...
4
votes
0answers
2k views

WMTS from MapProxy in QGIS and/or ArcGIS

My company wants to use imagery from a another company internally for a contract. That company's WMS has a 5+ second latency. Which I'm told is unacceptably slow. So I set up MapProxy and seeded the ...
4
votes
1answer
254 views

QGIS how to handle circular but non-closed lines

I use QGIS 2.18.3 and I have a shapefile with around 30,000 lines and a lot of invalid geometries. It is imported from a CAD project. I managed to solve most of the invalidities with the break ...
4
votes
1answer
1k views

Rotating symbols in QGIS

I have a vector symbol that I am using rule based style with. In the Rule properties tab I click on the SVG marker and change the "rotation" which is a field I have made to handle to the ...
3
votes
0answers
79 views

How to make buttons work from second window in my QGIS plugin?

I'm trying to develop a QGIS plugin. I already created a second window. In that second window, there are several buttons that I need them to work. I can't say I'm a programmer that's why I don't ...
3
votes
0answers
85 views

Calculating direction of polygon using other features? (QGIS)

In QGIS 2 or 3 I have some DEM rasters, on top of that vector layers with plots and buildings + pin (blue one) with coordinates of building. How to calculate position of garden? Is it n, ne, e, se, s,...
3
votes
0answers
756 views

QGIS tile cache not working

I'm new to QGIS and work on an air-gapped system where I have access only to QGIS 2.14.9-Essen. I create a WMS layer, which "works" but performance is abysmal. So I enable caching (Settings > Network) ...
3
votes
0answers
347 views

Unable to compute intersection between two polygons using PyQGIS?

I have two polygons in different layers. I am trying to find the intersect between the two polygons. Below a figure showing my test case. I initially wanted to find the intersect between the green ...
3
votes
0answers
113 views

Standalone Application QgsCoordinateReferenceSystem fails without OSGeo environment

I am writing a simple standalone QGis application. My code is like this: class MainForm(QtGui.QMainWindow, Ui_MainWindow): def __init__(self): super(MainForm, self).__init__() ...
3
votes
0answers
288 views

QGIS: Cropland Data Layer - how to add class names to .tif file?

I'm working with a clip of the Cropland Data Layer (raster), which has a number for each value coded to a crop type. I want to add these crop type / class names to the .tif file (and have them show up ...
3
votes
0answers
179 views

OSM Tools Plugin is broken for QGIS 2.8.6-Wien

When installing OSM Tools for QGIS Wien 2.8.6 I get an error: the plugin is broken python said no module named YAML. YAML is on my Linux Mint box 18 and I can't find documentation with Google or on ...
3
votes
0answers
184 views

How to transfer QGIS configurations to latest version?

I have QGIS 2.18.11 on my machine. There are saved wms, wfs and DB connections. After installing QGIS 3.0 I can see saved wms connections but no DB connection is listed in 3.0. Collegue's problem is ...
3
votes
0answers
1k views

Installing plugins for QGIS 2.18 on mac

I can't install any plugins on QGIS since updating to 2.18 (I am running High Sierra). I am connected to the QGIS Plugin Repository yet receive the error message: Plugin installation failed:Failed ...
3
votes
0answers
331 views

Why does Contours plugin crash QGIS 2.18?

I am running QGIS 2.18 on a mac and trying to use the Contours plugin. I've never had problems with it before but then I updated QGIS using Kyngchaos. Now Contours crashes QGIS when I choice "Filled ...
3
votes
0answers
308 views

Linking "value maps" together in PostGIS/QGIS where the values are user editable?

This is related to Limiting available values in dropdown field of QGIS form according to value selected in previous field?. Even though this has been marked as resolved the answer is not what I am ...
3
votes
0answers
420 views

minidump written to C: in QGIS PLUGIN

I have created a simple QGIS script using QGIS 2.18.3 and windows 10 and it works fine without errors.But I want to move that script to another PC where I have QGIS 2.6 and windows 7. I first copy-...
3
votes
0answers
186 views

Adding field to shp subset layer using PyQGIS?

This is an independent followup from my previous question: QGIS Python generate index field I have two files (points.shp, polylines.shp), each with a variable amount of sublayers of the given ...
3
votes
0answers
890 views

Plugins incorrectly being disabled due to "causing QGIS crash"

I have QGIS 2.14.0 installed on my machine (W7 x64, AMD FX-8150 3.6GHz, 8GB RAM, SSD) and I'm having issues with plugins not opening by default when I open QGIS. The message I get (for each plugin ...
3
votes
0answers
72 views

Is it possible to make a multiple line coordinates in QGIS 2.12.1 map comsposer?

I'm trying to display a 2 line coordinates, where the thousands are on the top row, and the units are on the lower row. I've tried to custom coordinates using the following expression: left(@...
3
votes
0answers
1k 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
0answers
368 views

QGIS 2.14 Processing plugin crashes - TypeError: must be string, not None

I've recently installed 2.14, and it worked fine for the first couple of days (Appart from Grass tools), including several program and computer reboots. Today I had this error show up Couldn't load ...

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