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

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33 views

QGIS feature subsets are incompatible with table joins. Bug?

When using QGIS 2.8.2, I am unable join a table to a layer that has a feature subset (Layer Properties > General > Feature Subset). For example, creating a feature subset on a layer prior to joining ...
2
votes
2answers
90 views

QGIS/Python script to generate random points many times

Good day. Can anybody provide a simple code to be run in the Python Console of QGIS (I am using 1.8 Lisboa) to generate X number of random points (say e.g. 5000) over a certain global shape of ...
3
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0answers
64 views

Which projection can I use to see alignments on great circles?

I want to put on a QGIS map some historical sites to check if they are aligned. If an alignement exists, the points should stay on a great circle (is this correct?). I want to visually verify this ...
3
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2answers
76 views

How can I move the toolbar if its holder is out of screen?

While I was editing the toolbar, the holder stayed out of the screen. so I can't move it. How can I fix it?
2
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2answers
35 views

Map canvas overlay layers QGIS

I built my own map canvas inside a plugin in QGIS and I want to add two layers (one by one) in order to overlay the two. I have this code: fileCI = "....\plugins\teste\test.shp" fileInfo = ...
3
votes
1answer
90 views

Speed of people measured by gps

I was tracking tourist's movement patterns in a city with GPS and I would like to know the speed of all participants (60). The data were recorded and saved in gpx files, so in order to open it and ...
1
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1answer
37 views

Why is SAGA from the Processing Plugin not recognised?

Similar to this post: SAGA algorithms don't work in QGIS 2.8 except the fact that SAGA does not appear at all in the Processing Toolbox: As a check, I used the Python Console with the following ...
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0answers
24 views

How to avoid “Handle bad layers” message when opening a QGIS project file?

Most of the time I have to reload all the layers when opening a QGIS project file (.qgs), which is pretty annoying. I didn't change the name of the files and folders and I didn't change the folder ...
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0answers
13 views

Cut polygon with polygon QGIS [duplicate]

I have two polygons. One sits mostly within the other (pink) and I would like to cut this from the other polygon (blue). This is a feature I have used before in MapInfo but struggling to find the ...
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0answers
23 views

migrate an application under 1.6 to 2.8

i would like to know what are the recoomandation if i want to update an application based on a old version of qgis in my case my application was written using the 1.6 qgis, and now we want to use it ...
2
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0answers
34 views

Generate ID for the grid of points from top-left corner down

I have a grid of points extracted from a raster. I need to give them a new ID value to be able to join values from it to another grid in rotated system of coordinates.The automatically generated ID ...
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0answers
39 views

Mean Shift Segmentation Error: The following layers were not correctly generated - QGIs + Orfeo Toobox

I have been trying to do an object based classification using QGis + Orfeo Toolbox. I downloaded the Q Gis 2.8.2 and OTB from OSGeo4W Network Installer. I am using OS Windows 7 enterprise. When I ...
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1answer
36 views

How to remove vector grid cells that don't overlap with features from a certain layer in QGIS?

I am working on displaying a road network with QGIS (2.4). Doing this I have a couple of layers, including a base network of roads, and my modified layer. All in all they become a huge network. ...
1
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1answer
37 views

Compile pluging for qgis 2.8.2 with pb_tool or Makefile, in windows

I created my pluging with pluging builder, after compile the resources file, i test my pluging in Qgis. I modify the ui file in QtDesigner, but i don't know how to compile it in order to see the ...
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0answers
31 views

import qgis geoprocessing tools in python os x 10.9.5

I'd like to use the python bindings from qgis, but in a standalone project. I need the geoprocessing tools for vectors. I updated QGIS (Wien - 2.8), python (3.4.3), etc. However, it always ends with ...
1
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2answers
81 views

NDVI from Landsat8 LandsatLook images

I have downloaded landsat image from this site and now Im wondering if i can get NDVI index from it. In raster calculator I have only 3 ranges, shouldnt be four? Or am I doing something ...
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0answers
46 views

QGIS python originalName() does not return actual original layer name

I am writing a Python QGIS Plugin, using QGIS version 2.6 as the basis for development. When loading data into the canvas programmatically, I am trying to maintain the spatialite table name as the ...
2
votes
1answer
44 views

Error Packaging QGIS 2.9.0

I am attempting to package QGIS from source and the creatensis.pl script is exiting with the error: Running NSIS Can't open script "Master'" running nsis failed [makensis -V1 ...
1
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1answer
17 views

Get page coordinates of QgsComposerMap

How do I get the coordinates in page units (i.e. millimetres) for a QgsComposerMap item? I can get the upper left coordinate using pos, but can't see any method that provides access to the width and ...
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0answers
36 views

problem with header in qgis 2.8

i have an old project based on qgis 1.6 i had to upgrade it to qgis 2.8 but during the make it seems that a lot of header or classes has disapeared by exemple in the 1.6 the classe ...
0
votes
1answer
32 views

How do i match Layers in QGIS

am trying to create a map, which shall show NRW ( a part of Germany) with some extra gimmiks. Those Gimmiks are Coordinate based locations of several Manufacturers. Later on i want to adjust the ...
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0answers
12 views

How to render visualizations for geospatial objects (the way QGIS does it) on web interface for end users, from PostGIS database? [duplicate]

I have existing geospatial objects in PostGIS. I can visualize it using QGIS. But I want to render these visualization on a web-interface for my users as a result of some queries in the database. I ...
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0answers
82 views

How to display missing objects in QGIS 2.8.2 cartogram?

I've just created cartogram using styles/graduated symbol. But there are some missing elements on the map. Objects without data in attribute table are not present on the map (NULL in corresponding ...
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0answers
22 views

'Locking' intervals in interval determination

Working with graduated maps in Qgis 2.8 I'd like to lock a certain interval value while letting Qgis determine the rest - in relation to eg. missing values. I know how to work with queries, but this ...
2
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1answer
63 views

How to extend line features up to their intersection point in QGIS?

Is there a tool or plugin in QGIS to extend line features up to their intersection point?
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0answers
22 views

Polygons in place of points on a grid in QGIS?

In QGIS, how can I create a shapefile with polygons of a known size (ie. rectangle 30m x 40m) placed on a grid with 1km spacing? That is, polygons in place of points on a 1km grid.
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0answers
63 views

extract x-y from a point created from lat/lon coordinate

Using QGIS 2.8.1, how can you create a point in WGS 84 using a lat/lon and extract X and Y value of this same point in CRS UTM34N. For eg, you have been given a lat 20 deg and lon 50 deg. Create a ...
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1answer
50 views

How to set CRS in QGIS using pyQGIS

This question is very similar to these one , but it's doesn't work for me. This is my try: ........ vlayer.setCrs(QgsCoordinateReferenceSystem(25830)) ...
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1answer
34 views

Labeling layers with Python in QGIS. LinePlacementFlags

How could I set LinePlacementFlags with Python in QGIS? My code is something like: palyr = QgsPalLayerSettings() palyr.readFromLayer(layer) palyr.enabled = True palyr.fieldName = "attribute" Then ...
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0answers
27 views

How do focused tests Diggle and Score Lawson-Waller in QGIS?

Is possible do the focal tests Diggle and Lawson and Waller using a add-on in QGIS? If it is, how, please????!!! About the tests: ...
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0answers
39 views

PostgreSQL owner/role administration for QGIS projects

What's the best way to administrate PostgreSQL roles for QGIS projects? I've created a separte schema for each of my QGIS projects. Is it possible to revoke all privileges except "select" for finished ...
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0answers
25 views

Forcing area calculation into miles in QGIS (without changing the PCS) [duplicate]

I'm working on an assignment that requires me to create an area column in miles without changing the projected coordinate system. ArcGIS has a tool that can do this ('Calculate Geometry')-- does QGIS ...
3
votes
1answer
109 views

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

I'm working with windows 8 32 bits OS and qgis 2.8.2. The qgis default installing path for ".qgis2" folder is C:\Users\image95.qgis2. This directory stores several usefull components like qgis ...
1
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1answer
67 views

How to load an (updating) point layer from Access?

I have a database table linked to the QGIS project which contains X,Y & Z coordinate information, which I can display in the Map View window of the project, after having used the “Points Layer ...
1
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0answers
26 views

Executing a QGIS model per feature of a polygon

I have just got into QGIS models and want to run the attached model per feature in a polygon shape file. I have been trying to do this in two ways and neither of them work. I tried find ...
2
votes
1answer
78 views

Get vertice information and apply to line segments using ArcGIS for Desktop (or QGIS)?

I've recently started tracking bike treks using Strava and I thought it would be interesting to do some analysis on my treks. I am able to import the GPX file into ArcMap and convert it to a point ...
1
vote
1answer
27 views

How to display the join field in a QGIS join?

Upon joining tables in QGIS (2.8.2) I am unable to view the join field in the resulting join. Additionally, the join field is not listed in the target table's Layer Properties, even though the other ...
2
votes
1answer
13 views

Joined Attributes not recognized in mean coordinates

I am trying to find mean coordinates of a shapefile to which I have joined a csv file for population attributes, but these will not show. I'm working with county data of each US state based on the ...
4
votes
1answer
55 views

Select a column like Primary Key in a View from PostGIS using PyQGIS in QGIS

Postgresql doesn't support Primary Key in views. When I load a postGIS view in QGIS "manually", I can choose the column that will be the Primary Key, but I would like to know if I can select a column ...
0
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0answers
22 views

Related Spation and non-spatial in QGIS

I am working with QGIS 2.6.1 by adding data from server using PostGIS. Now, I want to see the attribute information. So, how can relate the spatial with the information?
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0answers
45 views

How to relate a Spatial and Non Spatial table in PostGIS to be visualized in QGIS

first of all I'm quiet new in PostGIS. I'm working in pgadminIII with postGIS. I have in one database two tables. See the two tables SQL Pane. CREATE TABLE gw_body_characterisation2 ( ...
1
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1answer
23 views

Create statistics by features in QGIS [duplicate]

I've a polygon layer for parcels in a landscape protection area and a point layer, contains zoological data (e.g species, entities, etc.). How can I make a statics for each polygon, contains the list ...
2
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0answers
33 views

Is there limit on size of GeoJSON files that can be handled by QGIS? [closed]

I'm trying to load a GeoJSON file with about 5K features in QGIS, and it fails, saying Invalid Data Source without further details. If I remove features down to 1K, it works. Is there a limit on the ...
1
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0answers
24 views

Execute GRASS command within qgis phython console

We try to calculate catchments with the r.water.outlet function from python console. To do so we use the following code: import processing rlayer = QgsRasterLayer("/my/path/DrainageDirection.tif", ...
2
votes
2answers
41 views

QGIS joins 2 FIELDS

I. a new to GIS and mapping. Using QGIS. Have an excel with 4 columns (Region; District; village; number of cases) Have a shapefile with dots for villages with many columns including (Region ; ...
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0answers
24 views

Making virtual raster with average values [duplicate]

I'm working with many raster files. Is there a way to make virtual raster with average values in each pixel. (QGIS) It's for an NDVI index of summer months over 5 years.
1
vote
1answer
35 views

Merge lines while adding attributes spatially

What I have: A shapefile with multiple lines. Example: line 1: A -> B -> C with attributeX=5 line 2: A -> B -> D with attributeX=7 What I want Lines between each nodes with added attributes. ...
3
votes
1answer
38 views

Poor performance with storing large rasters in PostGIS and visualising in QGIS

my question concerns the use and performance of several software tools in conjunction, namely PostgreSQL, PostGIS, QGIS, and GDAL. I'm a long-time ArcGIS, Python, and R user who is interested in ...
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0answers
23 views

How to create ROI in Semi-Automatic Classification plugin QGIS

while trying to classify landsat images, I get the following problem: I click on the pixel I want to define a ROI, but the ROI polygon that the plugin creates appears in a different part of the image ...
2
votes
2answers
40 views

Why does QGIS Vector OpenStreetMap import lose features?

I'm attempting to use OSM data in QGIS 2.8.2. I've imported my data into SpatiaLite layers using the following steps: Vector -> OpenStreetMap -> Download Data... Vector -> OpenStreetMap -> Import ...