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

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29 views

How can I allocate a $rownum in reverse order in QGIS?

How can I allocate the $rownum value in reverse order in QGIS? I have a created a grid layer to use in an atlas and the ID allocated is from top left to bottom right - which is what I want if I want ...
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2answers
42 views

qgis: how to use 'max()' in an expression

I wanna make a rule-based style on the maximum value from a field. I set my expression like: max("fieldname") It returns every value instead of only the maximum one. Can anyone tell me the richt ...
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31 views

Making centeroids for vector grid

I need to add polygon centeroids to vector grid but I cant... i have output grid like polygon, but i cant choose layer to make centeroids I need it for R studio and pollution model of city, thx for ...
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55 views

QGIS tool for aggregating population data in fishnet

I'm looking for a tool or method to aggregate a vector fishnet based on a minimum value. Specifically, I have a fishnet containing a population value and I would like to join together cells that ...
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1answer
50 views

Use raster memory layer from QGIS processing result

I want to apply subsequent QGIS raster processing algorithms in a python script. I want to use memory layers for intermediate calculation results since I am only interested in the end result. As ...
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1answer
32 views

How to select from selection with PyQGIS?

The expression box has a handy "select from selection" button. Is there a way to emulate this with python? I have the basic expressions down, but can't find a way to do this.
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671 views

QGIS and Ubuntu 14.04 unmet dependency

I posted this on digitalocean, but it's imperative I resolve this problem. Freshly updated 14.04 and I went from trying qgis.org debian to the ubuntugis repo. Results: xx@XX:~$ sudo apt-get install ...
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1answer
37 views

Current field of view specific legends in QGIS

Is it possible to make QGIS generate a legend that is based only on the field visible in composer? There was a ticket marked as resolved 5months ago with this question but it doesnt divulge the ...
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49 views

How to get a layer by name in PyQGIS?

I have a plugin which finds buffer for list of cities, provided the distance. The state and city names are taken from the attribute table and gets filtered accordingly. What I want is My plugin should ...
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1answer
92 views

Qgis 2.8 problem with font size

I'm using Debian 7 and yesterday i had an update of Qgis 2.8. Since then I can't change font size and type, at labeling and print composer, whatever i pick it returns to the default "Free sans" size ...
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2answers
48 views

Transform from artificial coordinate system to a real one

I have spatial data generated in an Archaeological excavation which is in an artificial coordinate system and I want to convert it to a "real" coordinate system. To do this I took real coordinates ...
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1answer
58 views

How to add label to QgsVectorLayer by Python

my goal is to define label programmaticly for the case similar for the figure below: But didn't find any guidance how to do so using Python. I have a feeling it could be done using QgsLabel but ...
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2answers
24 views

QGIS - seem to have killed my 'Items Properties' panel

QGIS 2.6.1 Microsoft Windows 7 Relative Newbie to QGIS; old hand at drawing software Think I have corrupted this on my actual file that I'm working on. Yes, I know that I can right click and get ...
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25 views

Is there an out-of-the-box way to manage 1:n data in QGIS?

I think an image explains the question best: What I basically want to do is select the object, view its attributes and from there call the second table to view/edit/add status entries. Since I ...
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1answer
33 views

How to check the value of a single pixel in QGIS?

I was wondering how to check the value of a pixel at a mouse click in QGIS (as of 2.4). In ArcGIS, the "Identify" tool does the job for both rasters and vectors. However, in QGIS, the "Identify" tool ...
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2answers
29 views

QGIS dividing a raster by a polygons layer

I've got a raster image and I want to divide that raster by a polygon layer. There are just 7 polygons in the layer so i need to obtain 7 raster images as output. How can this done in QGIS?
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1answer
100 views

print composer and atlas feature on large dataset

this question could be very complicated, so I'll try to be as clear as I can. I have a polygon (hundreds of cells) that has a quite rich attribute table (more than 30 fields). Each field contains ...
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1answer
26 views

How to display symbols on a Raster in QGIS?

I have a raster file in which each cell has a numeric code which indicates that the cell is directed towards one of its eight neighbours. I am using QGIS to display each of the eight possible codes ...
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1answer
52 views

How to exclude a certain attribute from being added to the Processing script output layer?

I have a working script to split a layer by field attributes and save the single features as files: ##[User scripts]=group ##input=vector ##class_field=field input ##output=output file from ...
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2answers
86 views

How to batch process .txt files with X,Y data (in Arc or QGIS)?

I have a long list of .txt files that I need to convert to feature class. I can bring the table into ArcMap, right-click, Display X,Y Data, and it converts to a feature no problem. Is anyone aware ...
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1answer
40 views

Getting a number from QLineEdit and passing it to the buffer function

I am developing a plugin which finds buffer. In that i am using lineedit for getting distance from the user and pass it to the buffer function. My current code throws an error "'QLineEdit' object has ...
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1answer
25 views

if condition is false but output is true . what is the exact expression of greater than to bands value ('mjune@1'> 99.6:)

from qgis.core import * from qgis.gui import * from qgis.analysis import QgsRasterCalculator, QgsRasterCalculatorEntry from math import * from PyQt4.QtCore import QFileInfo import os from osgeo ...
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1answer
34 views

Loading multiple SpatiaLite layers into a single database

I have many SpatiaLite layers, each in a separate database. I want to load all these SpatiaLite layers into a single database. How can this be done?
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1answer
42 views

QGIS Composer Big Red X

I am working with QGIS version 2.01. I created a print composer to export the map with legend, scale bar and title to an image or pdf. When I opened my QGIS project again and went to my print ...
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1answer
33 views

Multiply whole column with the field calculator in QGIS

I have a layer with the field size. I did some mistake with the value and now I need the values multiplied by 16. But instead of going through 500 lines and recalculating them I would like QGIS to do ...
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1answer
25 views

What's the letter and word spacing unit in QGIS labeling?

I just want to know if letter and word spacing, in qgis labeling, are expressed in points, and if the value its absolute or relative to the font. I have searched a lot, but I can't find any ...
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56 views

How to delete a shapefile from a directory using QGIS?

I am using the following code to clip a shape file using processing tools via Python and would like to delete the clipped file from the directory. Here is my code. from PyQt4.QtCore import * from ...
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2answers
85 views

MultiLine field-name label referencing

A labeling routing (which is updated often) is being implemented via pyqgis and a QComboBox. The attached code below worked great, that is until needs for narrowed column headers spawned the use of ...
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1answer
62 views

Load PostGIS or Oracle Spatial Raster Layer using PyQGIS

How do we load Rasters stored in PostgreSQL-PostGIS or Oracle Spatial 11g into QGIS using PyQGIS? I am able to load vector layers from Oracle 11g with below code. What changes are necessary to add ...
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2answers
385 views

QGIS Photo2Shape plugin - error

I had Photo2Shape plugin installed on QGIS 2.4 (Windows 64 bit), following installation of 2.6.1 and an upgrade of the plugin itself Photo2Shape is now broken. Error message on install is "No module ...
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3answers
92 views

Using QGIS2Leaf plugin to export into leaflet but output results into browser crash?

Amateur GIS technician here, Just tried to export my converted cad cities pipelines into a shape files and then export it into leaflet using QGIS2Leaf but the browser crashes before the displaying the ...
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1answer
27 views

Adjust Fill style behavior QGIS

Does anyone know how one can change the Fill style option in QGIS? I need to use a diagonal pattern that does exist, but I need to adjust it. I have a cartography specification that defines the ...
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1answer
47 views

How to create a text file containing layer names in QGIS?

My QGIS ToC contains layer groups and some layers that do not belong to any group. I would like to create a text file containing the name of those layers that do not belong to any group. Is there an ...
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2answers
88 views

How to add 2 layers in qgis and display them at the same time

I added 2 layers in qgis using python but only one layer is shown on canvas. After clicking (anywhere on the canvas) both layers are displayed. layer = ...
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1answer
42 views

How to select features using an expression with pyqgis?

How can I select features with pyqgis using an expression? I tried to use an QgsExpression but the select method doesn't take it: exp = QgsExpression("'ogc_fid' = 482") cLayer = ...
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1answer
52 views

How to zoom to selected feature with QGIS Python Console

I want to select a feature by ID and zoom to it. I tried the following but the canvas doesn't change. Any ideas? canvas = qgis.utils.iface.mapCanvas() cLayer = canvas.currentLayer() cLayer.select(51) ...
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89 views

How to Add Oracle Spatial Tables to QGIS?

I've been playing qith QGIS Chugiak (2.4.0). I've been attempting to try to add Oracle Spatial tables (point, line and polygon feature classes) to desktop. The same tables I use in ArcGIS. I've ...
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2answers
58 views

QGIS2.6 postgis relation between tables

I have three tables in Postgis: points called location(gid (pkey),name) example (1,Paris) temperatures named Temp(idTemp(pkey),TempValue,date) example (1,12,2015-01-01) relation between the two: ...
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1answer
44 views

How to change the raster format using QGIS translate?

I tried to change a raster format from .tiff to .asc using Qgis's 'translate'. As a result, I get 3 files: a PRJ, XML and a file without extension just a plain file... What could it be happening? I ...
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1answer
16 views

Eliminating pixels of a Merged image

I need to change the value of pixels that where created in an image as a result of merging 2 rasters, this new pixels have a value of 0. The problem is, that there are pixels with 0 in the original ...
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1answer
76 views

How to Set SRID in Spatialite

How do you update the SRID in a SpatiaLite table? I am using the QspatiaLite plugin or the SpatiaLite_Gui program to send this SQL to the table: UPDATE myTable SET geom = SETSRID(geom,26910) ...but ...
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3answers
91 views

Can't use Raster Calculator with two different rasters

So, I have several maps like this one: And with the proximity tool and a coastline shapefile I made this output, representing the distance to shoreline: Now, I want to combine both using the ...
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2answers
121 views

Vector -> Geometry Tools -> Extract Nodes equivalent in PyQGIS API

My question is fairly straight-forward. Would anyone know the PyQGIS equivalent of the Extract Nodes tool in QGIS? I don't seem to find it in the API documentation. If you do, kindly share the ...
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2answers
50 views

How do I get UTM projected areas from a shape file created in QGIS?

I create a polygon (or point or line) .shp file in QGIS and it is automatically saved as WGS (as I understand, correct me if I'm wrong). That is fine by me despite being a bit inconvenient. Then I ...
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2answers
86 views

Issue in the popdown box (QComboBox) in QGIS 2.6 Python plugin

I had developed a plugin that counts the number of features for a layer in Qgis2.6. When i load a layer say 'Airport' for first time and click the pop-down box in the plugin,it lists the airport ...
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2answers
79 views

handling QgsVectorLayer (pyQGis begginer question)

I have a simple question. I am trying to start with pyQgis, but I have found it really hard to get a GOOD api Documentation, simple but yet useful. The one of you who did programming in the old ...
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1answer
74 views

Finding a vertical kilometer between 2 points with specified distance in QGIS

I'm new to GIS software. I want to find 2 points in selected area (lets say Czech Republic) with distance 5km or less and altitude difference 1000m or more. I know that I can use GMTED datasheet with ...
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1answer
40 views

How to use field calculator in QGIS to calculate new coordinates, and use that new columm to geolocate a layer's points

In a separate question, at How to shift a CRS by an observed offset, I asked about shifting a CRS to align the problems aligning data points with a satellite image obtained from OpenLayers. (They ...
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74 views

What is a memory vector layer in QGIS?

What is a memory vector layer and how does it relate to the vector layer? Background info: I have a volunteer working with my organization, because of financial reasons we have him using QGIS. He ...
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1answer
31 views

creating a new vector layer from a part of the current one [duplicate]

I am using qgis 2.6 for the first time. As I was using 2.2 previously, it was easy for me to create a new vector layer from a part of the current layer with the help of option "save selection as a new ...