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

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251 views

How to make a routable graph from a Point and a Line shapefile, using Networkx?

I have one shapefile which consists of all the streets in the study area, and another shapefile which has points representing origins and destinations. I would like to know if it's possible to find ...
1
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0answers
14 views

QGIS DBmanager import file append not working [duplicate]

I am using QGIS and connecting to Postgresql database. I want to import shapefile data into database table via DBmanager tool. But Append data to table selection is inactive like following image. I ...
2
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1answer
73 views

Is there a way to clip a polygon layer according to DEM elevation?

I have a polygon layer on top of a DEM. Is there a way to clip the polygon layer according to elevation, ie the clipped result being only those areas of the polygon layer between x and y altitude? ...
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1answer
50 views

QGIS GRASS plugin: r.composite quality loss

When using the r.composite tool within the GRASS plugin in QGIS, the result raster has a cell size of 150x150 while the input rasters have a cellsize of 30x30. Can this be overcome somehow or is this ...
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0answers
48 views

QGIS Fill Ring tool problem

Using the new (in 2.2) 'Fill Ring' tool and it doesn't seem to work correctly in all cases. It seems that if I try and digitise the new ring close to the polygon boundary, TWO (or more) geometries ...
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0answers
31 views

what is the math behind rasterization? Doubt [duplicate]

In Figure 4 you can see how the overlap is not complete (marked with circles). What I would like to know which algorithm that QGIS uses the rasterization? What is your standard? Is there a percentage ...
3
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1answer
378 views

How to make a Python script that does a task in QGIS?

When I run this code in QGIS Python console it works fine, but I want want to run it from an external Python script. What I want the script to do is: 1- Open QGIS 2- Run this code 3- Close QGIS from ...
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1answer
107 views

qgis's georeferencer renders my white map with a translucent blue tint, can I prevent this?

I'm running QGIS 2.0.1-Dufour on MacOSX and when loading a PNG or TIFF into qgis as a raster its always getting rendered with a blue tint. Here's what it looks like before being loaded into QGis's ...
2
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0answers
186 views

PyQGIS: Programmatically Adding Point Features via QgsMapToolEmitPoint

I've created a map tool for QGIS 2.0 Python plugin that emits a point with the click of the mouse. I'm trying to create an edit tool, adding a point feature at the emitted point while selecting ...
3
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2answers
631 views

How to automatically draw lines with a given angle from one single point in qgis 1.8?

I'm new to qgis so please be patient. I need to draw a bundle of lines all originating from the same point and with a 10° angle between each line (e.g. lines bearing at 0,10,20 ..90..110..220..350). I ...
1
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2answers
53 views

error using the QGIS “terrain profile” plug in

I have searched the home page for the "terrain profile" tool but have not found why I am getting error when trying to utilize it. Any ideas? I have a polyline and 4 dems ready to run the tool. Would ...
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3answers
220 views

What is the math behind rasterization?

I'm taking the first steps in QGIS (version 2.2 Valmiera) and I am having some difficulties in knowing what mathematical criterion that QGIS uses when converting polygons (shapefile) to raster. I'm ...
2
votes
1answer
291 views

Label all features of shapefile with PyQGIS

I have a problem when trying to label all features of a shapefile with a Python routine. If I open my shapefile in QGIS "by hand", and select a .qml with pre-defined label selection, the labels are ...
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0answers
100 views

Digitizing with OpenLayers Plugin seems incorrect

I am attempting to digitize some buildings based on floor plans using QGIS. To do this, I have taken the blueprints, georeferenced them against openlayers bing aerial plugin. I then digitized the ...
1
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1answer
506 views

Is there a SWAT model integration for QGIS?

I am trying to use SWAT (Soil and Water Assessment Tool) for watershed management activities. It is a set of commandline tools and needs a complex set of input data some of which can be generated from ...
0
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1answer
56 views

QGIS Python - Executing functions for multiple directories

I would like the user to select 2 directories, each directory having their own defined algorithms. For example: First_Directory will add a column to all shapefiles in the chosen directory; ...
5
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2answers
594 views

Calculating the average / MEAN of an attribute field in a QGIS model

I need to know how to calculate the average / mean of an attribute field in my point shape file. Is this possible to do with the field calculator? I just found the options min or max but not mean. The ...
1
vote
1answer
192 views

What does “PostgreSQL layer has no primary key.” when loading layer from database manager mean?

I have a complex join that I have working in the database manager but when I try and load it nothing appears and I found this in the logs: PostgreSQL layer has no primary key. What is actually ...
2
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1answer
197 views

Route to cover entire network

I have a road network where I have to cover every road for visual inspection. I need to design a route map for this task. What tools are available to a QGIS user? How would you describe the workflow ...
1
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1answer
213 views

Get Coordinates of Voronoi Polygon Vertices [duplicate]

Is there any chance to get the exact coordinatas of the voronoi polygons? I am using Qgis software and I have the "center" (redpoint) of the polygons and I would like to export the polygons corners ...
0
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0answers
94 views

QGISCloud in mobile QGIS

I’m new with QGIS mobile, I can’t open shapefile on QGISCloud using samsung note 8. Does anyone know how to do that? I haven’t found qgis plugin for mobile yet. Thank you
1
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1answer
272 views

Problem with CadTools plugin in QGIS 2.2

I've just downloaded the CadTools plugin from QGIS Plugins page (can't do this through QGIS itself as I'm behind a proxy) and after installation I keep getting an error saying that it "Couldn't load ...
0
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1answer
49 views

How to adjust spacing and alignment between legend symbol and text in Qgis

I'm getting some weird and seemingly random spaces between the symbol and text labels in the legend for the Qgis print composer. How can I set the symbols and text to align left/right or divide the ...
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0answers
93 views

Translate data from MapServer to Qgis server

Might you help me in this question: I've got operational Mapserver with shape- and map-files on it (*.shp *.map). How can I show them on Qgis server using Qgis web-client or Lizmap? This is my ...
2
votes
1answer
235 views

Why is the QGIS 2.2 database tab missing?

I have recently installed QGIS-2.2.0 but the Database tab in the top-menu bar is missing. It looks the main reason is missing libgdal1h library. But when I am installing it, it's removing ...
2
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1answer
201 views

Why does the file size increase after I clipped the polygons to be smaller?

I have a polygon layer that shows properties along a road. I want to create a kml-file of the polygons, and to downsize the file, I tried clipping the properties with a buffer. But, the filesize of ...
3
votes
1answer
51 views

Why are Google Mercator and UTM rotated towards each other?

Being a self-taught GIS user, I struggled a while before getting the grips on map projections. But now this: because I like to use OpenStreetMap as a background layer for orientation, I have saved my ...
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2answers
166 views

How do I mask a raster in TileMill?

I've tried just about every single TileMill compositing operation on the vector and raster layers in question, and I have to admit that I can't figure it out: How the heck can I mask a raster with a ...
0
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1answer
88 views

How to integrate pascal code into a QGIS model or plugin?

I have a console program that is written in pascal (lazarus) that reads in some raster files and parameter values as input. The code use dynamic 2D arrays to represent the rasters. I would like to ...
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2answers
239 views

TatukGIS SQLite Spatial vs. Spatialite

I must apologize in advance, I'm just getting into GIS and trying to figure things out. I have an SQLite spatial database that I'm pretty sure was created in TatukGIS. I've tried to open it in QGIS ...
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1answer
213 views

Is there a way to access the GeoProcessing tools in QGIS, in code

Is there a way to access the GeoProcessing tools in QGIS, in code? I want to find the Difference between two layers and make a new shapefile with the result.It can be manually done by selecting ...
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2answers
269 views

How to join data in postgis tables to form layer with subset of attributes

In QGIS I am trying to join data from two postgis tables. I can not figure out how to do this at sql because add layer tools seem to allow one to select just one table to filter on. Instead I ...
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1answer
196 views

label vector line with multiple attributes in QGIS

I have a line with two 2 attributes. I would like to display both information along with the line in frequent interval, one info above the line and the other is below the line. I am working in QGIS ...
2
votes
3answers
625 views

convert a shapefile into graph with nodes and edges

Is there a way to convert a shapefile into graph with nodes and edges(except networkx). I'm using qgis and I want to convert a road vector layer into a graph, so that I can use it to apply shortest ...
2
votes
2answers
378 views

QGIS/PostGIS: Select Counties within Region via Spatial Query

I'm using GQIS 2.2 and PostGIS on Postgresql 9.3. I have 5 regions in the contiguous United States. Each region has states, and each state has counties. I would like to think that the data I'm given ...
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2answers
62 views

shapefile terminology for key-value pair

In an .osm file, there are <TAG ... /> elements like <way visible="true" id="-4409" timestamp="1970-01-01T00:00:00Z" version="1"> <nd ref="-21845"/> <tag k="fcc" ...
5
votes
1answer
169 views

Is there a “Disperse Markers” tool for QGIS?

I am using ArcGIS, but either I would like to use QGIS and maybe want to switch completely later. A have a point overlapping problem, as a result of geocoding of addresses. I have not found any ...
2
votes
1answer
301 views

Does not show shortest path in networkx (in QGIS)

I used the following commands (in qgis console) to get the shortest path with astar algorithm. But the result shows 'NetworkXNoPath' every time. Why was that? Please help me to find a solution to this ...
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0answers
50 views

Is is possible to run the QGIS python module server side?

I'm pretty new to programming but I want to use the QGIS python module on a server. Basically I am trying to create a JPEG map programatically on a server. I already have a python script to create ...
3
votes
1answer
799 views

QGIS says “osgeo [python-gdal]” isn't installed on Mac

I know similar questions have been asked (like this one) -- but I'm encountering a unique problem. I installed GDAL complete 1.11 from KyngChaos, but when I open QGIS, I get the following error ...
0
votes
1answer
201 views

Issue loading layer from OpenLayers plugin in QGIS

I installed the OpenLayers plugin in QGIS and tried to load one of the layers. Regardless of which layer I try to load, I am getting an error message. See example: Does anyone know how to resolve ...
0
votes
1answer
1k views

Missing QGIS raster menu tools - '“osgeo [python-gdal]” module is missing'

I recently had to reinstall QGIS (version 2.2.0-9) and the raster menu is missing its tools. I understand that the GdalTools plugin must be installed and enabled. I have already installed the GDal ...
0
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2answers
293 views

Identifying clusters of points within a given distance

So I have a database of lats/longs representing incidents occurring on or near roadways. My goal is to identify the street block areas with the highest number of incidents in the database. I don't ...
0
votes
1answer
235 views

Why do I get these bands on my Height/Dem/Raster

I can't seem to get rid of them, and I've no idea (ok scrap that, I have a vauge idea) whats causing them. First an apology, yes this is quite a large pic apologies, but here goes: How to ...
0
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1answer
148 views

Issue clipping vector file with QGIS (geoprocessing tools)

I am trying to clip wind speed data (.shp format) to Canada's provincial boundaries (also .shp format). I am using the clip feature in vector > geoprocessing tools. For some reason the function always ...
2
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2answers
1k views

Qgis installation fails on Ubuntu 14.04 [closed]

I am having problems installing Qgis on Ubuntu 14.04 (Trusty). I tried several approaches: installing from the Ubuntu standard repos, installing from http://qgis.org/debian and installing from ...
0
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1answer
187 views

Searching closest region from Google Maps coordinates

Here is my problem. I'm mapping a region in google maps after that I'm saving the coordinates in PostGIS databse as geographic Polygon type. ST_GeographyFromText('SRID=4326;POLYGON((..))') The goal ...
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0answers
42 views

Rasterizing vector contour data: Python error message

would anyone know why qgis kicks up this error message (image attached) when using v.to.rast.attribute? the rasterise related to a contour set. i duplicated it twice to create 3 copies. the first ...
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2answers
106 views

Create Shapefile of all overlapping features from single Shapefile

I need to create a Shapefile out of another Spahefile that consists all overlaps of features within the initial Shapefile. I'm sure there is a simple solution using ArcMap or QGIS, but at the moment ...
2
votes
0answers
205 views

Create a non spatial index on an attribute in QGIS before joining two layers

I’m using QGIS 2.0.1 on Windows 7. I’m trying to join a .dbf which contains no spatial data to a shape file containing spatial data. Ideally I’d like to create an attribute index on the join field in ...