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

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osgeo4w not installing processing tools in QGIS toobox.

I have uninstalled and reinstalled QGIS several times from the OSGeo4W application. I have done this with no problem on several other times, but now I cannot get the tools to load. Most of the help ...
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9 views

Defining and exporting a path from discrete points in QGIS

I'm working with elevation data (NED, SRTM, etc.) in QGIS and I'm wondering how I might be able to pick a set of points from my map and export the coordinates to something like CSV. For example, I'd ...
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1answer
13 views

How to prompt for layer selection from python console in QGIS?

During script development it's useful to use the QGIS python console to test the same script on different layers. Currently I've been hardcoding layer strings and just swapping out but it isn't ...
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1answer
12 views

QGIS Treat null as zero in raster calculator

In QGIS - I have an irregularly shaped raster - I wish to clip an irregular area out of it (call it raster A) with that area set to null. I masked the area (vector polygon) I want to remove and used ...
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0answers
4 views

SegFault on create an EmptyDataSource From a typedef

I had to create a specific type of point, in order to do that I create a function that create a layer from shp file and data extract of the Code : typedef bool ( *createEmptyDataSourceProc ) ...
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1answer
17 views

Install QGIS on ubuntu using the compressed format qgis-2.8.3.tar.bz2

I just cant use apt install becuase slower internet connection and size of QGIS can you show me how to do insall using qgis-2.8.3.tar.bz2 file. I have tried decompressing and use the command ...
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0answers
12 views

How to remove temporary layer source files in QGIS

I am new to QGIS and python. Titles says it all. I'm modifying a plugin that creates some temporary files (layers) during it's run and I need to loop it a couple times. The algorithm works fine for ...
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2answers
17 views

Avoid intersection is missing QGIS 2.10, 2.8.2

I need to digitize a lot of polygons and I want to ease my work with the 'avoid intersection' button so that the new polygons do not overlap. In the manual I found (for version 2.6) that the button is ...
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1answer
23 views

pass custom command line arguments?

Is there a way to start QGIS with custom command line arguments and to access those arguments at runtime in a plugin? Background: I'm trying to start QGIS using a third party application(click on a ...
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1answer
32 views

Is it possible to remove small transparent outline effects between polygons?

after using the vectorizing tool I get the following result (picture). Around the cells you can see a small "boundary". This thin line is transparent and annoying. Is it possible to remove these small ...
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32 views

Coordinate transformation fails in QGIS

I am new to qgis, so this maybe a simple problem, but I don't know how to handle it. I have two layers: One layer is based on WGS84, the other on Gauss-Krueger zone 3 (GK). How can I successful ...
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1answer
23 views

Explanations for attributes QGIS

I have one column in my attribute table with attributes "1", "2" or "3". 1 = normal route 2 = special route because of the event (every year) 3 = special route because of the event and construction ...
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20 views

QGIS Georeference [on hold]

I am trying to georeference a scanned map I was given. I load it into QGIS Georeferencer and set up some control points (10 off in this case). The image seems to transform fine and I can see the ...
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0answers
8 views

Error using gdal IDW in processing script for postgis layer

I am running QGIS 2.10.1 and I am trying to use the processing toolbox to interpolate a point layer. If I use a shape file with all the default settings it works well but if I use a point layer coming ...
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1answer
20 views

QGIS legend without print composer

I'm trying to export a series of images using the TimeManager plugin. I'd like to have a legend on each, to demonstrate why my datapoints are sized the way that they are (i.e. this circle size ...
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21 views

new shape file addition problem

I am using QGIS 2.8.2 version, me unable to add new shape file layer. After drawing the line when I right click the mouse the line was disappearing (fig2). The new layer being shown in layer window ...
-7
votes
1answer
61 views

Why there is no EPSG code in ArcMap? [on hold]

In Arcmap, when you right click on the layer >> go to properties >> select source tab there you see the properties of projection. I cannot understand why ESRI did not managed to add SRID EPSG in ...
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0answers
28 views

How to calculate Areas of NDVI with Qgis? [duplicate]

How to calculate the area occupied by each pixel of a raster NDVI in QGIS? Excuse me, I do not speak English. Ya calcule el NDVI de una imagen Landsat con Qgis, como calcular el área ocupada por ...
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2answers
29 views

Query ShapeFile to get informations from coordinates

I have a shapefile that represents all the Hydrological Basins in the world. You can download the file from here: ...
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2answers
47 views

Google Maps Openlayer plugin not aligned with the OpenStreetMap building layer in QGIS

I am working on an OpenStreeetMap (OSM) building layer (I download the imposm geojson in city Dar Es Salaam, Tanzania from https://mapzen.com/data/metro-extracts and used the building layer) and the ...
1
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1answer
15 views

External Standalone QGIS Application with Default Toolbars

I want to develop a standalone application and add the default digitizing and advanced digitizing tools in QGIS as-is on my application through PyQGIS. Is it similar the way you add the navigation ...
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15 views

How to set QGIS mapCanvas to exact values

My QGIS 2.8.2 standalone app's mapCanvas fills a central widget with a fixed quadratic size x=y=1000 pixels. When I set the mapCanvas extent() to an area defined quadratic as well given by a ...
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26 views

Creating new empty vector layer that has same set of atributes as another layer and then copying subset of features into it

I am new to both Python and QGIS. Here's a sample of my code: unique = layer.uniqueValues(index) attributes = layer..dataProvider().fields().toList() assistant_layer = QgsVectorLayer("Point", ...
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0answers
11 views

Merge raster layers error

Is there an issue with the SAGA-tool "Mosaicking rasters"? I tried it with different rasters. In Sage itself it works fine. Algorithmus Mosaick raster layers startet... io_gdal 0 -TRANSFORM ...
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2answers
59 views

QGIS 2.10.1 on Mac/ Multiple versions on Mac

I have Version 2.8.2 running fine on a recent iMac running Yosemitee. I have tried the install of 2.10.1 from http://www.kyngchaos.com/software/qgis but it doesn't work. I would like to be able to ...
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23 views

Running a custom function on each line of a PostGIS table

I am trying to run a custom function on each parcel in a PostGIS table, (in this case its a function that finds the standard deviation value of the pixels intersecting a raster) Here is the code for ...
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2answers
27 views

Map with just City/Country/River/etc names.

I am looking for a plug in or a map, that only has the names of the countries and cities and other urban and/or geographical features. Does anyone have or know of such a map/plugin. I'v e been ...
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0answers
11 views

64 Bit Win 8.1 grass 7 missing dependency

I searched for an solution but couldn't find it. Problem is: previous i had an working grass 7 within qgis 2.6/2.8 I know that there were more people with the same issue. When executing a grass 7 ...
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0answers
17 views

NDVI Workflow Problems, Red Channel Seems High Causing Low NDVI value?

I did some searching but nothing came up around this. I'm trying to verify a workflow from images to an NDVI to verify I have a basic workflow correct. Process images example dataset through ...
2
votes
1answer
43 views

How to apply a radial fill to a voronoi polygon centred on its original home point in QGIS?

I'm working with a point layer (airports from OpenFlights), and I want to create a map of distance to the nearest airport. I thought I might be able to do this by using radial fill on the voronoi ...
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11 views

Using Lastile in Qgis

I want to tile one large las tile into few minor. But i just cant get it done. My original LAS file have around 30mil points and i want to get 5 smaller LAS files with 5mil points in it. What is ...
2
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2answers
86 views

How do I make equidistant circles covering the whole globe in QGIS?

What's the simplest way to make equidistant circles in PostGIS/QGIS? (my software versions are Postgres 9.3, PostGIS is 2.1, QGIS 2.10) I tried this in PostGIS, but the circles that come near or ...
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1answer
69 views

Sorting points based on Northing and Easting

I have around 1320 point/centroid features in a shapefile for my research plots. Each point/centroid has X and Y coordinate associated with them which were calculated using Field Calculator > Geometry ...
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25 views

Displaying heatmap with large number of dense points of interest in QGIS?

I am currently trying to make heatmaps of bird observations in an area. I have had a lot of success making the actual heatmaps for most birds, except the ones that are extremely abundant. I use the ...
2
votes
1answer
19 views

OTF reprojection and reprojecting layer not working in QGIS

more troubles in QGIS. I georeferenced this raster in Corrego Alegre UTM23S and loaded up, so project CRS automatically changed to that. So far so good. I need it to be however in WGS84 UTM 23S. None ...
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1answer
58 views

Qgis network analysis why find vertex return always -1

I'm trying to compute the shortest path between points using the QGIS networkanalysis library. But the graph.findVertex always return -1. Basically what I'm trying to do is : 1/ Given a set of ...
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1answer
25 views

Loop to check multiple polygons overlap in r

I have a set of polygons (available here: http://ulozto.cz/x39ELbFt/polygons-zip) created in QGis and processed in R. I would like to know if they are overlapping or not, and if yes, where is the ...
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1answer
37 views

Can't get my QGIS external map to display on Ubuntu trusty: QObject::connect: Cannot connect (null) error

I've been following along the examples from the book "Building Mapping Applications with QGIS and for the life of me I can't figure out why my shape files aren't loading and displaying in the app ...
1
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1answer
45 views

My QGIS plugin shows GUI but not Works. How to get Error log?

I am new to PyQgis. I made a simple calculator with PyQt4, now I am trying to run it under QGIS. I connected calculator as plugin, and tested it, its GUI works without error but it does not calculates ...
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0answers
16 views

Prevent Overlapping Features in QGIS from Being Faded

I have multiple layers in QGIS that I've set as transparent so I can see their respective features. However, I would like one layer (showing proportionally sized points) to NOT fade when it overlaps ...
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0answers
11 views

How can I extract the latitude and longitude from a s57 File [duplicate]

I had to extract the longitude and latitude from a s57 file, in order to superpose a satelite view from the same point. These coordinate will allow me to get the exact position on google map by ...
2
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2answers
55 views

How can I import shapefile in python?

How can I import a shapefile in python? from PyQt4.QtCore import QSettings, QTranslator, qVersion, QCoreApplication from PyQt4.QtGui import QAction, QIcon, QFileDialog # Initialize Qt resources from ...
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0answers
18 views

What solutions to use QGIS as insert tool for a Postgres relationnal database?

I have a Postgres/PostGIS relational database and I would like to use QGIS as an interface for inserting data. The thing is that my database is quite complex and I need my tool to handle the following ...
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0answers
15 views

QGIS measure growth in special directions

I want to measure the growth of different areas in special directions. The same as in this article of M.S.Moeller on page 5 (Figure 5 and 6). But I don't know how to build such a Wind Rose in Qgis. Do ...
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1answer
17 views

automated selection by attributes and location within another Layer

I have two Polygon Layers. Layer A are Districts of a City and Layer B are Blocks of a City. Currently i'm working with QGIS 2.6.1 and i don't have access to any other GIS. What i'm trying to do is: ...
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0answers
30 views

Merge layers (SAGA) ERROR

with QGIS 2.10 it is not possible to merge vector layers with the "Processing-Saga" tool (merge layers). The following error log comes up: Algorithmus Merge layers startet... shapes_tools "Merge ...
2
votes
1answer
30 views

Calculating distances across land only

I am trying to do point to point distances in QGIS but I have points to point distances that are being calculated across oceans. Given people don't generally fly around cities does anyone know a way ...
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0answers
17 views

unsupervised classification in qgis (Orfeo toolbox)

I want to run an unsupervised classification of two landsat images in qgis. Therefor I want to compute a kMeans and a SOM (self organizing maps classification). Unfortunately it doesnt work. I tried ...
2
votes
1answer
33 views

How to calculate the 3D length of line segment in QGIS?

I've been looking through all of the GRASS commands in the QGIS 2.10 processing toolbox and it seems like one of these must be able to do this but I haven't found one yet. There is 'v.sample' which ...
2
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0answers
33 views

How do you merge overlapping .asc files in QGIS with topography and bathymetry?

Firstly, apologies for any incorrect terminology - this is my first time trying to manipulate GIS data. I have two files. The first is higher resolution (SRTM) topography data for a region of islands ...