Questions tagged [qgis-2]

Version 2.x of QGIS (previously Quantum GIS)

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6
votes
1answer
1k views

Points in Polygon missing from QGIS 2.16.x?

Looking to do a basic Hex analyis with some random points within the Gulf of Mexico. I created a hex grid from MMQGIS Under my Vector tool - Analysis tools, I dont have Points in Polygon. Is it ...
5
votes
2answers
17k 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 ...
5
votes
1answer
293 views

Open project made on OSX lion on a windows computer with QGIS

I made a project in my personal computer (mac OS Xlion) and now I would like to modify it on my work computer (windows 7), Is it possible?
4
votes
2answers
7k 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 ...
4
votes
1answer
458 views

Is it possible to save frequently used expressions in QGIS?

Is there any way to save frequently used expressions in the selection or field calculator dialogs? Obviously I can cut and paste them into a file where I might save them, but I mean within the context ...
3
votes
1answer
971 views

Why does “Join attributes by location” fail to compute sums when used in a model?

If I use "Join attributes by location" from the menu it works fine but if I'm using it within the Processing modeler it's not working. I want to sum up previously selected records having a field area ...
3
votes
1answer
2k views

How to style a vector layer in QGIS using hexadecimal color code stored in attribute?

I have a polygon shapefile storing hexadecimal color codes in a specific attribute. gid | label | color ---------+-----------+------------ 1 | Crops | #FF5F2C 2 | Forest ...
2
votes
1answer
224 views

SVG symbol colors differences in QGIS 2.12?

I don't understand why SVG symbols, which are colors changeable in the symbol default installation like this airplane: whereas there symbols like the transport bus station, and lighting symbol (that ...
2
votes
1answer
2k views

How to randomly select from existing points within each polygon?

I have a polygon layer (where each feature has a class attribute), and a point layer, and there are at least 10 points within each feature of the polygon. Is there a way to randomly select only "k" ...
2
votes
2answers
1k views

Predefined Coordinate Systems missing in QGIS 2

in QGis 1.8 were lots of predefined coordinate systems (national projections). Where have they all gone in qgis 2.0? I specifically need the Gauß-Krüger-Projections Zone 1 to 5. Is there any plugin ...
1
vote
1answer
819 views

gdal for reprojection of VSCMO VIIRS data

I downloaded h5 VIIRS file by CLASS NOOA website. In particular I am interested in Snow Cover Binary Maps EDR and I need to reproject them in lat/lon or UTM. I tried to use gdal warp to this aim but,...
1
vote
1answer
158 views

Inherited values between polygons in QGIS? [duplicate]

In this project, I have three polygons, see the image below "Polygons_From", includes input attributes, i.g. "Value_1", "Value_2", "Value_3", and $area for each quadrate (on the image there are two ...
0
votes
1answer
2k views

NameError: name 'QImage' is not defined [closed]

Traceback (most recent call last): File "<input>", line 1, in <module> File "F:/QGIS/bin/test.py", line 6, in <module> img = QImage(QSize(800,600), QImage....
21
votes
1answer
3k 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 ...
9
votes
3answers
3k views

Performing a Spatial Query in a loop in PyQGIS

What I am trying to do: loop through a point shapefile and select each point that falls into a polygon. The following code is inspired by a spatial query example I found in a book: mitte_path = r"D:\...
12
votes
2answers
2k views

Setting a default value in a QGIS field

I would like to add in a layer's field a default value. I mean, every time a new feature is created, that field would be automatically filled with the default value. In my case the default value ...
7
votes
2answers
6k 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 ...
3
votes
3answers
2k views

Measure distances between specific features in QGIS for Desktop

I'm completely new using PyQGIS and developing plugins. Currently I have a layer with the X and Y coordinates of electric distribution poles, where each pole is a feature. What I need to do is ...
16
votes
2answers
1k views

Is it possible to write a label expression in qgis that displays the label at a given coordinate?

I am using the QGIS expression builder for the label properties of my data. Is it possible to put different parts of the label in different coordinates on the map? For instance I have a linestring ...
7
votes
1answer
10k views

QGIS and SQL Server Spatial Tables Performance

I'm trying to get a SQL Server 2008 R2 spatial database up and running to streamline the production of maps using QGIS. Currently I just have a handful of spatial tables (a postcode level point table ...
6
votes
2answers
4k views

How to change default path for “.qgis2” folder on Windows?

I'm working with Windows 8 32Bit OS and QGIS 2.8.2. The QGIS default installing path for ".qgis2" folder is C:\Users\image95\\.qgis2. This directory stores several useful components like QGIS ...
6
votes
1answer
196 views

How to setup default toolbars and menu item?

I need to customize the UI for a group of users at another office. I want to turn off a bunch of toolbars and menus that are not needed. I know how to save my configurations (Settings -> ...
5
votes
1answer
3k views

Relation Reference to simulate filtered drop-down lists

I have a layer of Land Uses that has a 3-tiered classification system (basically so that it can be broken down for different uses by other people). I have managed to create Project Relations and use ...
4
votes
2answers
2k views

PIP no longer works with QGIS 2.18.x Python (TLS version no longer supported)

We've run into a problem installing Python packages (using pip) for use with QGIS 2.18.x (error messages copied below) Our diagnosis is that: Pypi now requires TLSv1.2 support (http using TLSv1.0 ...
8
votes
2answers
1k views

QGIS 2.4: Basemap.at is displayed in poor quality

I have a huge problem displaying the austrian Basemap.at WMTS Service in QGIS 2.4. When I add the service, qgis logs multiple errors on failed tile requests. When I zoom into the map, it is displayed ...
8
votes
3answers
3k views

QGIS equivalent to ArcGIS Aggregate Polygons?

I am looking for a tool in QGIS 2.40 that performs the function ArcGIS refers to as Aggregate Polygons. Basically it takes a group of polygons within a specified distance and creates a concave hull ...
6
votes
3answers
14k views

Cleaning topological errors using QGIS? [closed]

I am a new QGIS 2.0 user. I was so impressed the new default tool, Topology Checker, in this new version. But, hundreds errors are bothering me for cleaning up features. Is it possible to clean ...
5
votes
0answers
488 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 ...
4
votes
1answer
2k views

QGIS Not Importing ExtendedData from Self-Exported KML?

I've been scouring the internet for the past few hours, and I just can't seem to figure it out! I am using QGIS 2.4.0-Chugiak. Here are my simple steps: 1) I create a new ShapeFile (Type: Polygon) ...
4
votes
2answers
641 views

Filling a field in a layer using a spatial relation with another layer/shapefile?

I want to know how I can fill in a column of a layer based on a certain relation criteria to another layer. In my case I want the column "straat" in my "bomen" shapefile filled in with the value's of "...
3
votes
4answers
3k views

System variable PATH overwritten in QGIS?

The system env variable 'PATH' seems to be overwritten in Qgis, replacing it with their own values. Not sure if it was intended or not. Anyway in version 2.2, I could solve it by go into settings and ...
3
votes
1answer
1k views

PyQGIS reload a QGIS plugin

I have a plugin that has a psycopg2 connection to a PostGIS database. When i close GUI with the X-Button and open it again, all the widgets are filled with the data from before. It looks like the X is ...
3
votes
2answers
1k views

Create Intersecting lines and remove dangles [closed]

I have 3 cases shown in the image. In all of them i want to intersect the lines and remove dangles using python in Qgis python console so afterwards i can make a plugin for this work in qgis.In case ...
1
vote
1answer
254 views

Merging isolines into polygons in QGIS, building an isochrone map

There is a set of isolines produced with v.net.iso. It shows distances in meteres [400, 800, 1200, and everything further] from a certain point. My desired output is an Isochrone map. However, I do ...
1
vote
1answer
1k views

Aligning labels with line connecting feature to its label in QGIS?

I have labelled a points layer by defining a line between points and labels, because points were overlapping too much. Using additional columns in the points layer attributes table (LABEL_X and ...
11
votes
2answers
11k views

Is there a way in qgis 2.0 to prevent overlapping labels?

Is there a way in qgis 2.0 to prevent overlapping labels? I have a layer with a large geographical extent, which means a hell of a lot of labels. Many of them collide and it looks really bad. Is ...
7
votes
1answer
3k views

Change NODATA pixel value in raster to arbitrary value

I want to change the value in all pixels that are currently 0 to 800 in QGIS 2.6.1. 0 is listed as the no-data value in Properties > Transparency. I have unchecked the No Data Value box there. Then I ...
7
votes
1answer
2k views

How to use qgis:selectbylocation in PyQGIS?

I am trying to use the processing toolbox to perform a spatial query (points in polygon). I am not sure how to use the tool and I keep getting Error: Wrong number of parameters. Here is my script: ...
7
votes
5answers
3k views

How to place labels under a vector layer? [duplicate]

I want to place the labeling under a layer. In QGIS 2.2 apparently the label appears automatically at the top. Can someone help me. (see attachment) example:
5
votes
1answer
8k views

How to change the type of a column of an attribute table in QGIS? [duplicate]

So I want to change one of the columns in my table from string to real. How am I supposed to do that?
4
votes
2answers
3k views

Access all plugin from QGIS Modeler (Sextante)

I read that it is not possible to access to all of the installed QGIS plugins from the Graphical Modeler (QGIS 2.0.1). It would be great, in defining the model in the Graphical Modeler, if the user ...
4
votes
1answer
975 views

Setting different context menu actions for each layer type with PyQGIS

I want to set different actions(context menu) for vectors,rasters,etc . class MyMenuProvider(QgsLayerTreeViewMenuProvider): def __init__(self, view): QgsLayerTreeViewMenuProvider.__init__(self) ...
4
votes
2answers
662 views

Determining when layer visibility is turned ON or OFF (changed) in QGIS plugin?

I need to update a vector layer's data when the visibility is turned back on. My update does not occur when the visibility is off. To what signal do I need to connect to catch the visibility change?
4
votes
2answers
1k views

PyGIS remove QgisVertexMarker from scene

I am writing a plugin that includes interaction with the map. Therefore I use a QgsMapTool. It is possible for a user to mark a point on the map. When the user clicks a red X is drawn on the mapCanvas ...
3
votes
2answers
750 views

Adding ArcGIS-FeatureServer-Layer to QGIS using PyQGIS?

I have a password protected ArcGIS-FeatureServer Service, the service provides 25 layers. Using "Add Layer --> Add ArcGIS-FeatureServer-Layer" works like it should. Is there any way to add these ...
3
votes
2answers
3k 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 ...
3
votes
1answer
971 views

Change default layer name in QGIS 2.18

In QGIS 2.18, new vector layers resulting from QGIS tools have a default name related to the corresponding tool. For example, when I perform the "Lines to polygons" operation (under QGIS Vector menu), ...
2
votes
3answers
6k views

How to split polygon into equal segments in QGIS?

I try to split polygon layer into equal length segments of 1000m: The attribute table of the layer is: I have read those links but didn't find a solution to my question: How to split a vector in ...
2
votes
0answers
401 views

QGIS 2.4.0-Chugiak: How to produce raster colour map

By carefully deriving the NDVI values from Landsat Band 3 and Band 4 after doing atmospheric correction by applying DOS1 method in semi-automatic classification Plugin QGIS, I was to calculate the ...
1
vote
1answer
2k views

Creating multiple lines label in QGIS?

I try to create a multiple lines label for this this polygon: I red How to create multiline labels in QGIS? QGIS, Multiple lines and wrap on character? and tried to use the "wordwrap" function ...

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