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

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Exporting only certain fields from a PostGIS table using QGIS Python

I'm trying to export tables from a PostGIS database into MapInfo TAB files, but only certain rows and columns. I have my rows exporting right, using a query, but I'm stuck on just getting the columns ...
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2 views

No export dialog on QGIS 2.8 and 2.10 with Mac OS X Yosemite?

I'm trying to work out the map making tutorial here: http://www.qgistutorials.com/en/docs/making_a_map.html When I try to export an image or pdf or even print the map I built in the composer, I ...
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0answers
3 views

2.10 program group option to open QGIS with GRASS

I have installed QGIS 2.10 on Windows 8. I cannot find the 'option' to start QGIS with GRASS - as has been previously answered. Have I possibly missed something in the install? Is this 'missing' ...
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0answers
9 views

Display or export gdal_translate exponential scaling equation

I have an GeoTiff raster that contains elevation information at each pixel. As OpenLayers 2 can't display GeoTiff, I convert it to a PNG image and have to apply an exponential scale so the resulting ...
2
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1answer
25 views

Plotting points on a map based on address text string of location

This may be a naive question, but I'll try anyway. I am working in QGIS, and I have a shape file with more than 2000 rows containing information about specific trees in a botanical garden; their ...
1
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0answers
15 views

Project do not open anymore because of a minidump [duplicate]

I have closed my project two days ago and this message appeared : minidump déposé dans C:\Users\wwf-adm\AppData\Local\Temp\qgis-20150903-171144-3780-1392-8fdd08a.dmp When I try to open my project, I ...
1
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0answers
13 views

Problem creating polygon in a layer

I am working in c++ qt4.8.5 and api qgis 2.8.2 c++. In my application I had to put polygon to define attractive zone. I found a great post in stackexchange (86812). I have based my on this post and on ...
2
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1answer
42 views

How to fix QGIS Plugins crashing with “NameError: name 'pyplugin_installer' is not defined”?

I recently switched to Windows 10 and therefor did a clean Windows and QGIS 2.10.1 Install. QGIS worked fine, I reinstalled all Plugins, that I used to have. No Problems. Today I switched on the PC ...
3
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1answer
41 views

Tilted projection in QGIS

I'm trying to add tpers projection as a custom projection in QGIS 2.10.1 In the Custom crs dialog I'm adding the proj.4 text: +proj=tpers +h=500000000 +lat_0=19 +lon_0=99 +x_0=0 +y_0=0 +a=6371000 ...
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0answers
25 views

How to best populate points within a polygon with a set of rules

I've got a polygon (a Circle) with a certain size. I want to put points inside it, as much as I can, but with a set of rules : Points can't be near each other, up to 500 meters. Points can't be near ...
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1answer
31 views

QGIS Processing Plugin Not Loading “RuntimeError: maximum recursion depth exceeded in cmp”

I am having serious issues with my QGIS program regarding the Processing Plugin. Upon start-up and if I turn on the plugin within the program. I have uninstalled and reinstalled the program. Have ...
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0answers
15 views

Handling features as events [on hold]

I have a question related to handling features dynamically. In the two desktop GIS systems QGIS and ArcGIS we can import CSV files or database tables as XY events. These can be handled as dynamic ...
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0answers
28 views

QGIS Generating a Lat/Long Degree Grid in Composer

I made a map in WGS84, which is positioned and referenced correctly. Now I loaded the map into the Composer and added a grid, with horizontal and vertical lines each 500 world units (m). When I ...
4
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0answers
47 views

How can I average point features spatially in QGIS?

I have a GPX file with track points and I want to average the points spatially to improve accuracy of the point feature. I can't just make a polygon and find its centroid as the number of overlapping ...
1
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1answer
17 views

How to create a specific svg file with data from a feature

I am working in c++/ QT4.8.5, with qgis api c++ 2.8.2 I have to display a dynamic icon for a feature. some of the data change periodically and in order to display the change i need a svg that can get ...
1
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1answer
27 views

QgsExpression using complex sql and python subsitution

I have a sql statement i am running in postgres fine and would like to transfer it to a QgsExpression mainly because I have loaded the layer in Qgis. My sql is: select column a,column b from table1 ...
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0answers
12 views

Tracing a raster layer in QGIS [duplicate]

I have a basic map I would like to trace into vector form in QGIS. The map is just a JPEG and has no coordinate reference data. Whenever I import it into QGIS, it ends up as a tiny speck at 0,0. How ...
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0answers
16 views

Qgis 2.10 unable to add a new feature in spatialite via sql function “GeomFromText”

Using Python code in my plugin the function in sql language "GeomFromText(POINT(X Y))" gives the following error: "OperationalError: no such function: GeomFromText" Plugin functions in previous ...
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2answers
32 views

Syntax error in parameter formula of field calculator funtion

I'm using a QGIS 2.8.1 in windows. Have some doubts with syntax when use string in python console. I want to use the field calculator funtion like: processing.runalg('qgis:fieldcalculator', input, ...
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1answer
34 views

messed up shapefile attribute table text

I have a .shp file from AutoCad imported to QGIS (using _MAPEXPORT > text in AutoCad) and this is what happens to text in attribute table - example: {\Fsimplex|c0;O\Fsimplex|c238;Š\Fsimplex|c0; ...
4
votes
1answer
39 views

Exporting Contours from QGIS into AutoCAD [duplicate]

I'm trying to export contour lines from QGIS into standard AutoCAD but I'm not having much luck. It does not seem to matter what type of file I select as the output during the contour creating (eg. ...
2
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1answer
33 views

How to reduce points by proximity

I got a layer with over 4 million points. The distance between the points are 1 meter. How can i reduce the data so that no points have less than e.g. 10 meters between them?
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0answers
31 views

Polygons within Polygons Spatial Analysis

I have a polygon layer of planning applications and I am wondering if anyone can give any advice and or has seen or written a blog post that might point me in the direction of creating relationships ...
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0answers
27 views

About performance of qgis with big layer or a lot of layer

does anyone has a feedback on the performance of a big layer by exemple : I have a layer with 100 features, each feature contains specifics attributes with dynamic data, the data change each second ...
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0answers
11 views

GeoExplorer not display the associated table to a layer

GeoExplorer shows the table information associated with a layer of 2 ways: Information button: clicking on the map is displayed a tab corresponding to the polygon attributes where you click. Query ...
1
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1answer
18 views

SVG To Shapefile [duplicate]

Is it possible to draw out some SVG shapes in Illustrator or Inkscape and convert them to Shapefile using GDAL or QGIS (or something else perhaps?). I have an image that I can easily georeference, ...
1
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1answer
27 views

Calculating field on insert (real time) using QGIS?

We use QGIS as a field application. We like to calculate with a input value and then also calculate with the result of the calculation Example: Liters: 1000 -> Liter per container: "this has to be ...
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0answers
22 views

How to add coordinates to an image in QGIS? [duplicate]

I use QGIS 2.10. I have a map image without any coordinate or boundary info. I need to convert it to kml file and before this, I need to add specific coordinate info for this map. How can I add ...
2
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2answers
35 views

How to visualize updating lines of bearing from a point

I'm working on a project where I need to visualize a constantly updating line of bearing from a point, based on degree of rotation around that point. My plan is to design a line feature with an ...
2
votes
1answer
35 views

How can I use a DBF layer in an R script in QGIS?

How can I use a DBF layer in an R script in QGIS? For example, I can input a vector by using ##Layer=vector, and a CSV table with ##Table=table, but it will fail if the table is based on a DBF file. ...
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1answer
33 views

Paths with least elevation gain

I have a DEM of a city with numerous hills and a shapefile of the city streets. I want to find the five paths from a low point A to a high point B on the street network that involve the least ...
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0answers
19 views

32Bit QGIS 2.10 Problems with Gdal WMS TMS google maps layer

I have been using gdal wms layers to view various basemaps in QGIS. I am using this technique rather than open layers because this I can reproject gdal WMS layers as needed. When I get close to the ...
0
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1answer
42 views

How can i calculate the distance to the nearest five neighbors for a polygon layer?

Data set (shape file) contains polygons. How can I calculate the distance to the nearest 5 polygons in the data set in QGIS?
2
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3answers
59 views

How to host QGIS threejs outputs?

Is there a free simple way to serve / host the .html files the awesome Qgis2threejs plug-in produces? I have tried using Google Drive as shown here and here without success. Also had same results ...
2
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0answers
21 views

How to show only some layers in the QGIS legend

I hope this is still kind of a QGIS related question. My QGIS 2.8.2 standalone app provides several decorating layers (e.g. cartographic grid, background layers, reference points) which should be not ...
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0answers
12 views

Zonal statistics shifted

I am working with QGIS (newbie). I have a raster map with 0.5degrees resolution. I created a 0.5degrees width grid layer and I compute zonal statistics from the raster. My problem is that it seems to ...
2
votes
1answer
52 views

Why I see a gap between ESRI Robinson WGS84 (EPSG 54030) VS QGIS Robinson WGS84 (EPSG 54030)?

Does anybody know why there a gap appearing between two point layers create with ESRI and QGIS when I a reproject, from the same source file, to Robinson ? The source coordinate system and ...
2
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0answers
75 views
+50

Deciding variables for image classification?

The results of an image classification may vary A LOT depending on the variables you use from the beginning. Number of classes, minimum class size, sample interval, atmospheric corrections, ...
1
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2answers
37 views

is it possible programmatically to rotate a svg of the feature without rotate all feature

I am working on a project that need to move and update the shape of the feature of the layer. I am working in c++/ QT4.8.5 and qgis api c++ 2.8.2. In my Layer I have a lot of features, each feature ...
2
votes
1answer
28 views

Recast data from one geographic standard to another

I'm working right now a project looking at medical labour supply in rural areas in Australia. I aim to use STATA for most of this analysis, but a change in geographic standards by the Australian ...
2
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0answers
20 views

QGIS Set Composer Legend to shrink the font size to fit

QGIS 2.10.1. I have read that it is "impossible to make the legend smaller then its contents". Is there a way to set the legend to shrink the font size when re-sizing the bounding box? Or when you ...
3
votes
1answer
67 views

What projection to use to get a game map into QGIS?

I have built and maintain a SWTOR game map atlas. At the moment, it's all static jpg maps, but I would like to get the info into an actual GIS software to get more functionality and make my website ...
3
votes
0answers
20 views

How to randomly select three points in each polygon?

I have two layers: first layer includes polygons of districts, second layer containts points (phytocoenological relevées). The goal is to create a new layer that will contain max 3 randomly selected ...
2
votes
1answer
29 views

qgis 2.8.2 always produces minidump on exit

QGIS 2.8.2 on windows 8.1 produces the below error every time it is closed. Anyone have any ideas as to why or possible fixes ?
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0answers
16 views

Text box with automated coordinate reference system in use on Qgis

Using an expression, is it possible to automatically fill a text box placed on the map (in the composer) showing the reference coordinate system of the project? If possible, how would that expression ...
0
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1answer
24 views

Creating an intersecting linestring layer from two polygon layers using some tolerance

I have two postgis layers: The first layer contains the sidewalks of my town (polygons in blue). The second one contains the pavements (roads) of my town (polygons in brown). The map looks like ...
1
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1answer
43 views

How to find the intersection length between two polygons using python

I have two polygons and i want to find the intersection line length between these polygons. for geom1,geom2 in itertools.permutations(selection,r=2): intersection ...
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0answers
22 views

qgis python: select on screen and change (pre-set) properties accordingly

I have a map with different zones where I have drawn isochrones -where I will arrive within 15 min, within 30 min and so on. The picture attached shows the 15-120 min isochrones. This is set as a ...
4
votes
2answers
87 views

How to create a consecutive alphanumeric column in a QGIS attribute table?

I am trying to create a column in the attribute table such that each cell lable is a prefix (M) follwed by a unique number ie M1, M2,.. etc
4
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2answers
126 views

Way to find minimum value from a group of values - QGIS?

I'm wondering if there is a way to find the minimum value of a group within QGIS? Basically I need to find the minimum distance of each unique value in a table of about 5000 records. I can do the ...