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

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How to read landsat images from Amazon S3 using python?

I would like to read and process landsat images from Amazon using pyton thanks,
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162 views

Extract Elevation of Points from DEM using Python QGIS or GRASS

I am utterly new to GIS, so please bear with me if I am providing incomplete information here. I have a DEM file (.dt2). What I am looking to do is as follows: take a series of points specified as ...
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120 views

QGIS: How to add a second polygon that is exactly 5km larger in all directions?

Given is a map with an airport. Within a distance of 5km around the runway there is a so called no fly zone for drones (in Switzerland). I want to show this zone in a map. What I would like to do is ...
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2answers
158 views

changing pixel values using raster calculator Qgis

How could I convert a value of 32767 to a 0 using raster calculator in QGIS?
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252 views

How to draw a perfect circle with a set radius in meters on map?

Following this istructions on how to draw a circle I can make buffer layer on each point I need. I am not able to draw perfects circle because the buffer will be elliptic? The CSR is EPSG:4326 - WGS ...
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2k views

how to generate a NDVI in QGIS [closed]

i have tried using raster calculator to generate NDVI and tried searching for but couldn't find it. is there any other way to extract NDVI and what are the procedures to generate NDVI in QGIS.
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465 views

How to add polygon height in QGIS or PostGIS?

Is there an easy way to set the height of polygons in QGIS or PostGIS? I am trying to visualize polygons by turning them into volumes (same shape at the base and roof, but with walls). I would then ...
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246 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 ...
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1answer
146 views

Changing $id in a shapefile in QGIS

I need to change the id (feature.id() in the python API or $id in the field calculator) of for features in shapefile layers in qgis, and I need to do it in Python. Is there a way? I tried something ...
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321 views

JPEG base map doesn't match shapefile locations

Relative Newbie Question: I have Civil War earthworks tied to the State Plane Coordinate system with a jpeg of the terrain as a 100k scale USGS Quad of the area that is not georeferenced. When I work ...
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35 views

Is possible to create a new column of QGIS?

I want to create a new column according to the column A & column B. Column A 1 2 3 Column B A B C New Column 1:A 2:B 3:C How can I do that in QGIS? Thanks.
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113 views

How to install maps2winbugs for QGIS?

I have got a maps2winbugs.dll file, but what should I do to install it into QGIS, sorry for the first time using this software, doesn't have any experients in C or R.
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95 views

How can i stop rendering Qgis

In my python plugin ,i select features from a vector layer dynamically using a loop and executing : VectorLayer.select(feature.id()) when i start the loop, the selection become very slow because ...
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2answers
1k views

Using OS Mastermap SLDs in QGIS

In an answer to a question asked by @Canningmister, @tjmgis posted an excellent answer Styling OS Vectormap Local in QGIS? about making OS SLD files work in QGIS. As an amateur user who uses QGIS to ...
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1answer
746 views

How to remove shapefile polygon vertex marker points in QGIS 1.8.0

I have created a shapefile layer and drawn a polygon to show the boundary of a woodland. How can I edit the polygon to remove the crosses that denote the intersection of two points on the boundary?
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2answers
527 views

How to create a MultiLineString feature with a postgis layer in QGIS

I have troubles handling with MultiLineStrings in QGIS. I added the table where I defined a column as geometry(MultiLineString, 31468) as a postgis layer in QGIS. Now I want to create features with ...
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1answer
50 views

Is it possible to install qgis plugin in a specific non default directory?

Is it possible to install a plugin to a specific directory e.g. D:\folder instead of the default one .qgis\python\plugin? Furthermore, can QGIS access plugins from different directories and folders?
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2answers
899 views

How to install Shapely, but got stuck into Python language

I have a MAC OSX 10.7.5 and am trying to learn how to use QGIS. Following a couple of tutorials I came to know I have to install shapely. I followed the instructions by the multi-cited ...
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2answers
1k views

Is QGIS suitable to create maps with image popups?

I am a new user of QGIS and was wondering if I came across the right software to achieve my goal. Long story short, I am trying to create a map with markups of various buildings. Once I click on a ...
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58 views

How to find the overlap of three polygons?

I have three polygon areas showing different land types and I want to create a new layer based on where the three layers overlap each other. I thought this was a subtraction query but havent been able ...
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1answer
72 views

pgRouting:routing problems using reverse_cost

I saw this post:Routing issues with pgrouting, and try the ability of reverse_cost. As the result of this post, if there is only one way to go from one node to another, even though the reverse_cost ...
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2answers
133 views

Query for Creating a buffer around a particular point

I am working on a project for ambulance management using GIS. using Qgis,Postgresql,Postgis I am finding it difficult querying using St_dwithin as well as St_buffer. My aim is to find any hospitals ...
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757 views

Python module “shapely.wkb” missing

I am trying to follow a tutorial from here http://qgistips.spatialthoughts.com/2012/12/find-neighbor-polygons-in-layer-in-qgis.html#more I have downloaded the relevant python script and edited it as ...
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1answer
92 views

QGIS exporting shapfile with proper projection

Can someone walk through the proper way to set a projection and export the shapefile so it will properly open up in another GIS program? I'm having trouble.
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1answer
97 views

Set QGIS (on android and/or linux) to use a custom .qgs file by default when opened.

Need to have QGIS open with all my settings/layers/projections etc by default. Created a .qgs file that has all this info in it. Using Android and Ubuntu. Tried a shortcut to the .qgs file in ...
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49 views

QGIS2WEB Error when exporting to Leaflet/OL3

I am having all kinds of problems with the QGIS plugins fr exporting my map to Leaflet or OL3. Whenever I try to preview my project I just get a white screen with nothing. Then when I try to Export to ...
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45 views

How can we export shapfile to svg format using Pyqgis

I am doing a project where i have to export file from shapefile to svg format using Pyqgis. i have read some articles regarding simplesvg plugin but i don't know how can we achieve the same task using ...
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2answers
75 views

QGIS2Leaf Plugin installation error “cannot import name AlgorithmDecorator”

I have been using the qgis2leaf plugin and succeeded in creating interactive maps, adding legend, photos, etc. But suddenly I noticed that the OSM base layer has disappeared and the polygons are not ...
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3answers
69 views

Subtracting polygon from another in same layer using QGIS?

I need to subtract a polygon from another bigger one, in the same layer. How can I do this?
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2answers
93 views

Geoserver WFS-T not saving edits from QGIS to MS SQL layer

I added a MS SQL layer from my Geoserver to QGIS. It will save changes for attributes in the table and it will save the file if I delete features. However, if I add a feature or change a feature, it ...
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2answers
117 views

US map shape distorted in QGIS

I am very new to QGIS and mapping. I am trying to load a US state map shapefile in QGIS. But the problem is it does not look like another US state map available on the internet. The upper part looks ...
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2answers
102 views

How can I generate batch of coordinates from linestring to simulate driving on map?

I have a openlayers map and I want to simulate driving a route on it. I would like to draw a line (using GPX tool) and create gps coordinates (preferred with advancing time stamp) so I can query them ...
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1answer
56 views

What's the PostGIS equivalent to Extract Nodes in fTools / QGIS? [duplicate]

I'm looking to convert Park polygons from OSM into points. The QGIS fTools Extract Nodes tool will convert a polygon to points at the vertices. What is the equivalent function or work-flow in ...
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1answer
85 views

Tools for map animations

I am preparing some visualizations of data (mainly animated choropleths), and I am looking for suitable tools. Ideally, I am looking for something similar to this kind of animated infographics. So, I ...
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1answer
64 views

Reading .csv file in QGIS [duplicate]

I am trying to join a .csv file with a .shp file in QGIS but QGIS is unable to read the data in my .csv file as it indicated that the variables are string of length and precision 0. As a result, I am ...
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1answer
40 views

osm2pgsql doesn't run in a QGis plugin

I have a problem with osm2pgsql when it runs in a qgis plugin. The function i use looks like this: osm2pgsql = "osm2pgsql -s -d {databaseName} -U {databaseUser} -H {databaseHost} -E ...
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1answer
885 views

QGIS Processing error with SAGA, “output layer could not be open”

QGIS 2.4.0 SAGA GIS 2.0.8 DESCRIPTION ERROR when processing with SAGA. I used the "Shapes to Grid" function. The error given: "Oooops! The following output layers could not be open". This error ...
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1answer
233 views

How do I pin all labels in QGIS?

How can I pin all my labels in QGIS 2.2/2.4 (Data Defined Labels) without clicking every single label?
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1answer
48 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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2answers
236 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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2answers
61 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" ...
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1answer
58 views

style creation in QGIS

I want to create a line style in QGIS (model is attached here with), Any body can help me?, please help me.
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1answer
165 views

cut square from geotiff

i want to make a 3d modell out of the mount everest and some other mountains. what i need therefore is a 14km² square around the peak from the mountain. so basically i use qgis to extract the area ...
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1answer
129 views

Mac QGIS files to Windows Arc GIS compatibility

If I download QGIS on to Mac will the shapefiles and layers I create be compatible with ESRI ArcGIS 10.1 on windows?
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2answers
223 views

Have I created a valid Spatialite database?

I didn't manage to find the better way to populate the exisiting Spatialite database with new computed data than just creating new columns and filling them in the Python script. You can see that the ...
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1answer
125 views

How to join information from an excel table to a road feature in QGIS?

I'm working with GQIS 2.2.0 Valmiera. I've made a shapefile of a road that consists in a single line. Now I want to add information that I have in an excel table about several point in the road. How ...
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436 views

How to remove black box around georeferenced grayscale image in QGIS?

i'am trying to georeference a grayscale image (*.tif) in QGIS 2.2.0 Valmeria. It is working but QGIS draws a black box around the georeferenced raster image. If i use the option set 0 transparent, not ...
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1answer
428 views

Link Google Earth with QGis

I was wondering if it was possible to link Google Earth files (KML, KMZ) to a QGIS project. The main idea would be that if you'd add a point with coordinates in Google Earth, this point would be added ...
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2answers
1k views

How to install PostGIS and OpenLayers plugins?

I am new to QGIS and have installed the QGIS v 2.2.0. For adding google map as a base layer I need to install OpenLayers plugin. I also need to add the PostGIS plugin for DB management purpose. Can ...
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2answers
451 views

Best way to create/draw a map (especially indoor)

I'm currently developing an indoor map/room plan for an university project. I've already searched through stackexchange to figure it out but I couldn't find anything similar. So what I currently do ...