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

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1answer
437 views

Python geoJSON module create a FeatureCollection with CRS, QGIS doesn't recognize CRS

I am curious if my geoJSON created with the geoJSON python module has a valid CRS. The manual on github specifies a feature collection like so: from geojson import Feature, Point, FeatureCollection ...
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1answer
43 views

Is it possible to run actions directly from the map canvas?

Is it possible to run actions directly from the map canvas in Qgis? If yes how can I do that?
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0answers
307 views

How to calculate a population weighted centroid using a raster and shape file in QGIS?

I am very new to QGIS so please help me with a step by step answer. I have a raster file with population count and a shape file based on a large population and shape file. I have successfully created ...
0
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1answer
124 views

How to access the map coordinates show in QGIS status bar?

Is there a way to access the map coordinates show in qgis status bar? I found only this, iface.mainWindow().statusBar().currentMessage() But I know it's not the way. Or is there any way to capture ...
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1answer
138 views

QGIS still not rendering WMS layers

Similar to Neil's question of March 8th 2013: QGIS not rendering WMS layers I can down load the BGS 1:50K bedrock and superficial deposits maps OK, but they don't render except at scales greater ...
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0answers
79 views

How to export the legend (Layers Panel) as an image in QGIS using the Python console?

I want to export the Legend (the Layers Panel) as an image using the python console.
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1answer
172 views

How to calculate highway lengths using QGIS? [closed]

I need to create a network of highways in 8 states of the USA. Eventually, I need their length, the speed and if possible average daily traffic volume, I don't know how to extract this information. ...
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2answers
86 views

How to bring all “tourism:attraction” from points table and polygon table together?

Im using OSM data as osm2pgsql-import (from extract.bbbike.org). And I want to draw all attractions ("tourism" = 'attraction'). The most of the attractions I found in the planet_osm_point table. But ...
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1answer
125 views

How to convert boundaries in image to polygons in QGIS

I have an image from a cities districts and their boundaries and I need them as polygons in QGIS. I tried "Raster -> Conversion -> Polygonize (Raster to vector)" as described here, but that ...
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1answer
292 views

Using gdal merge correctly?

Currently trying to use gdal_merge within qgis to stack three raster bands, the command it's showing is like this: gdal_merge.bat -separate -of GTiff -o out.tif "LC80190302014126LGN00_B4.TIF" ...
3
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2answers
297 views

How to select all files in a directory for merging in Processing?

I'm writing a generic script which involves writing shapefiles to a directory which are then merged together. After writing the files out to the Output folder, I'm trying to get the ...
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1answer
209 views

How to colour contour lines in .shp file when the lines are not meeting in QGIS?

I am doing bathymetry analysis, where I would like to color the contours one by one in the case land is rising (or sea level going down). There is a comprehensive explanation about coloring contours ...
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0answers
78 views

How to calculate the area of overlapping buffers within a single layer

I am very new to GIS, so don't know if this is EXTREMELY easy or impossible. I have GPS coordinates for stores (about 15000) for which I have created a buffer zone around each store location ...
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1answer
75 views

Is it possible to set symbol layers always on top?

Is it possible to set symbols always on top, also if the layer with the symbol is drawn under another layer? Example: My layer order is like that: Streets (top) Buildings Landuse (bottom) The ...
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0answers
48 views

Why does the “calculate” button remain gray in Group Stats Plugin?

I'm trying to use the Group Stats Plugin. I found your tutorial and I wanted to post a comment but I have seen that it is not possible then I thought to write here. Unfortunately I can not use the ...
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2answers
354 views

How to resample a raster to higher resolution in QGIS?

I'm fitting a SDM using R. A requirement is that all environmental predictor layers have the same extent, origin and resolution. I have high resolution bathymetry data (25m) that I will resample to ...
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1answer
65 views

How can I convert SRTEXT to PROJ4TEXT with QGIS

I have a SRTEXT like this: GEOGCS["My Data",DATUM["Not specified (..... I want to get PROJ4TEXT of this STREXT. Can I get it from QGIS. Because I want to insert it in Postgresql SPATIAL_REF_SYS ...
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1answer
50 views

Attribute table in map composer is limited to 99 rows. How to change it?

I am using Qgis 2.2. I am about to create a cadastral index map, which are showing the parcels in specific gridcells, also there is an attribute table connected controlled by an atlas function. So by ...
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2answers
497 views

Using ST_split to split a line feature using nearby points

I have a line shapefile and a point shapefile, and the line has just one segment and its attribute table, the point shapefile has points near the line above, not on it and the close ...
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1answer
48 views

Why are some QGIS 2.2 bar graphs not displayed?

I created a vector layer containing all European countries and some double information about them. I'd like to show this information for every object in a bar graph. My problem is that the bar graphs ...
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1answer
966 views

TIFF to MBTILES conversion on a mac

I have a large number of tiff files (map tiles) along with tab and tfw file types as part of an Ordnance Survey download. This is for an offline iOS app. I managed to get the tiffs into QGIS with ...
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2answers
256 views

Where to find Metropolitan Statistical Area (MSA) KML data? [duplicate]

Hello GIS stackexchange, GIS is not my field, so I apologize if my question is very basic. I need this data for a odd job at work. I have been unsuccessful in finding the data from Google ...
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1answer
32 views

QGIS Custom CRS has some glitches

I am georectifying scanned versions of Survey of India maps, which are in Everest spheroid and india_nepal datum. The exact parameters are: +proj=longlat +a=6377301.243 +b=6356100.2284 ...
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0answers
59 views

Converting/clipping KML to shapefile in QGIS without truncating field information (data)?

While I am clipping KML file by using polygon shapefile in QGIS, filed information (data) are truncating .Anybody can suggest a solution for this one.The same data losing issue occurring, at the time ...
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2answers
310 views

Exporting to 2D (Arcview 3.0 compatible) shapefile in QGIS?

I need to run my shapefiles through a web mapping application which is incompatible with 3D shapefiles. At present I run them through the FME Universal Translator in Mapinfo, which enables you to ...
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0answers
22 views

Update joined tables fields when the mysql database is updated

Using Qgis i joined feature tables with tables from my mysql database. I imported the database 's tables as new vector layers. Is there any way to update the joined tables fields each time mysql ...
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0answers
422 views

QGIS GRASS plugin missing!

I just installed QGIS version 2.2.0-Valmiera on my mac with OS X. First I installed all required frameworks. QGIS is running, but the Grass plugin is not existing. In the toolbox the grass tools are ...
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1answer
48 views

Why does Points in polygon create empty PNTCNT column from OSM points?

I tried to use the Points in polygon tool in qgis 2.2.0 and it worked fine as long as I used my own points. When I tried to 'count' the points generated from OSM layers both from dowloaded ...
4
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1answer
148 views

Can I use a QGIS geometry in a Python PostGIS query?

I have a "Python Init function" for the attribute form in QGIS, which is called when I add a new geometry. I can access the geometry of the newly created feature like this geom = feature.geometry() ...
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1answer
244 views

Labels appear and disappear for no apparent reason using QGIS?

I'm going through the Alaska sample data tutorial for QGIS 2.2.0. Some of the lake labels appear and disappear at different scales when zooming. At 1:314,460 Becharof is visible, but Lower Ugashik ...
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1answer
62 views

How to put marker on vector layer with lat/lon on QGIS [duplicate]

I have a vector layer, and bunch of lat/lon values. I want to put markers on the vector layer for each lat/lon pair. I have never used QGis, would you help with it. thanks.
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1answer
205 views

Convert Road layer shapefile into a graph

I'm going to use Astar algorithm to find a path between two selected points.And I used the following code for that.Is there any way I could convert my Road Layer shapefile into a graph, which can be ...
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0answers
151 views

QGIS 2.2.0 GRASS not worked

I use QGIS 2.2.0 on Windows 8 64 bit. I try to install use Standalone installer and OSGeo4W and still get the error And then i start GRASS C:\Program Files (x86)\GRASS 6.4.2>grass64 ╬╪╚┴╩└: ...
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0answers
146 views

How to add a large inset svg or pdf in QGIS 2.3 print composer?

I have a 48x36 wall map that will include 5 large inset maps, the largest of which is almost 11x17. Due to a bug with html annotations, I need to export each inset individually then include them as ...
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1answer
282 views

QGIS Slope Classification Issues

I am very new to QGIS for the primary purpose of creating a slopes layer so we know where slopes are above 15% or 20% or whatever we finally decide. I have used our DEM to create a slope geotif and ...
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1answer
118 views

How to filter data by category, then map only maximum-value row for each?

I'm building a consolidated map of all transit systems in my area in QGIS. I have a GTFS dataset of bus lines, and it includes shapes for every trip on every route in the system (as it should), but ...
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1answer
730 views

QGIS contours smoothing and cleaning

Trying to utilize the contour extraction QGIS tool but having trouble creating smoothed contours. The smooth, generalize, and dissolve tools have not worked for me. Also the plugin for contours ...
2
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1answer
88 views

Is it possible to create Rule-Based Styling with $geometry intersecting a second layer?

I am trying to create a rule-based style based on geometries from another layer. I have found an example that does exactly what I want, except that it uses a geometry from WKT: intersects( ...
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4answers
251 views

How to make an editable City Map from OSM data?

I want to make a map of Cardiff, Wales, showing features useful to tourists, e.g. roads with road names, parks, museums, other POIs, etc. I want the final map to be clear to read - simple roads and ...
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1answer
83 views

shp2pgsql data appent without gid

I have a shape file, I opened it in QGIS that has columns in attribute table named CITY_NAME, POPULATION and I have a database table in Posqgresql that has columns named gid (primary key), ...
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1answer
348 views

Convert shape file to kml without losing symbols

I am using QGIS 2.2 and want to convert a shape file containing point coordinates with userdefined svg-symbols to a kml file. Everything seems to work. The orginal file is in WGS 84 / UTM zone 32N ...
3
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2answers
116 views

Method for automatic aggregation of polys with sparse data

I am part of a project on presenting health related data on maps. In order to maximize the analytical usefulness of the data, we wish to divide them into as small areas as possible. However, to ...
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3answers
2k views

Calculating slope in percentage

I'm working with qgis, v. 2.0.1. I have several soil types. They are (amongst others) described with slope indications. I already calculated the slope from the dtm in degrees, but as de description of ...
2
votes
1answer
192 views

How to add an interpolation raster from the python console in QGIS?

I'm trying to add an interpolation layer based on an existing vector layer by using the Python Console (initially in the menu Raster/Interpolation), but can't find anything related in the ...
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1answer
199 views

How to open QGIS using VBA?

Using VBA, I want to open QGIS (the actual GUI) and execute a simple script through the Python console or the editor.
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2answers
505 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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2answers
190 views

How to split a (road) buffer using the centerline?

I have a road centreline dataset which I have buffered using the road width. I used the standard QGIS buffer tool. I realise for my analysis I actually need to split the road buffer in half and ...
2
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1answer
413 views

How to undo misclicks while drawing a polygon?

I'm trying to draw some polygons in QGIS 2.2 and I lose it, because everytime I misclick, I don't find a way to undo that point and start drawing again. I'm sure there's a way. Does anyone know it?
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3answers
43 views

Adding combined footage to points from the beginning of a line

I'm trying to add the footage of each point from the beginning of the line to the end. There are around 4k vertexes between the two ends that I need to put the footage from the beginning of the line ...
1
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1answer
390 views

Reprojecting a raster DEM from meters to feet using QGIS?

Is there a tool in QGIS that does the same as reprojecting a raster DEM from meters to feet as in ArcGIS's 3D Analyst > Raster Math > Times ?