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

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52 views

Dissolve Polygons by attribute leaves empty spaces

I am trying to dissolve polygons based on the same attribute using QGIS 2.8.2 (Wien). I use Vector, Geo Processing Tools, Dissolve and then I select the attribute. The data is Postal Sector in Uk and ...
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0answers
13 views

combining spatial and numerical queries in an expression

I would like to build an expression to return the largest value of a field within a source layer where it is contained within a polygon of the open layer. I want this expression to write the result to ...
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1answer
43 views

Generate maps from different columns of shapefile with QGIS

I have a shapefile with N columns describing different attributes of some features. I would like to generate a grid of maps, where each map is a different column. Visually, I'm thinking of something ...
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0answers
27 views

QGIS 'Save As' Reprojection Produces Different Results from ogr2ogr command line

Another 3857 vs 4326 question. When I reproject from EPSG:3857 to EPSG:4326 (and from .shp to .geojson) via the QGIS 'Save As' dialog, I get results that display in the expected place on Google Maps. ...
2
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1answer
40 views

How do I edit multiple features at one time?

In my case, there are about 30 overlaid features. How do I select all and edit them at one time? I want to reshape the features, mainly using the node tool to reshape a straight line into a (fake) ...
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1answer
51 views

How can I eliminate leftover border/boundary in QGIS?

I am trying to generate a shapefile which contains the unincorporated areas of St. Louis County, Missouri. I'm using two shapefiles: St. Louis County from the 2012 census, followed by St. Louis ...
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0answers
23 views

How to get QGIS to display grayscale of an SRTM geotiff?

I cannot get QGIS to recognise my SRTM geotiff as having any grayscale elevation data. In the screenshots below, opening the geotiff file in MicroDEM by default hillshades and pseudocolors the ...
2
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1answer
44 views

How to conduct an inner join with QGIS?

My QGIS (2.8.2) joins always result in an outer join. How do I create an inner join with QGIS?
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1answer
21 views

Importing Edge List into QGIS?

I have a CSV edge list such as follows: Lat1,Lon1,Lat2,Lon2 93.41823,-104.324324,93.41828,-104.324320 93.40110,-104.310552,93.40108,-104.310557 ... Is there a way to import such a CSV file into ...
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0answers
44 views

Convert manual colored maps to vector

Is there a way to colorimetrically and automatically vectorize georeferenced rasters that came from manually colored, scanned maps? Currently we Print the topography maps 20k scale --> hand-coloring ...
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0answers
33 views

Spatial join with multiple intersecting features

I have a polygon dataset representing pavement areas broken up by year of construction and a roads centerline dataset that contains values for remaining service life (RSL). I want to spatially join ...
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0answers
19 views

How to remove lines made with a PostGIS query automatically if origin is not in the map window?

I have a PostGIS point layer with labels. I moved these points because they were too close. To connect label and point, I created a line vector layer which was made with a query in the DB-Manager ...
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0answers
6 views

Problems with rasterization through QGIS Modeler

My goal is to rasterize a vector polygon-based shapefile. Whenever I run in the modeler or even from the Processing Toolbox the Rasterize tool of GDAL, I receive a raster layer that's not good for ...
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0answers
20 views

Hex grid from layer bounds issue

I'm trying to use the 'Hex grid from layer bounds" script to reproduce the simple "Mapping density with hexagonal grids" from the Learning GIS book. When I run the script "as is" I get the error: ...
2
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1answer
38 views

How can I apply a color ramp to a shape file layer in QGIS 2.8?

How can I apply a color ramp to a shape file layer to show something simple like population variance? If this was ArcGIS, I would do it by using the Quantities tab in Symbology but I have been unable ...
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0answers
21 views

Finding how many points are in polygon of layer in specific time using QGIS?

I have the layer that I created with the number of earthquakes in each region in the last 400 years. I want to know the number of earthquakes that occurred in one specific region prior to 1900. How ...
1
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1answer
38 views

Field calculater in Python console from QGIS

I have some doubts in syntax of processing.runalg(qgis:fieldcalculator) in python console of QGIS. I want to create a new field in a shapefile and calculate this formula: [D_PATRICIA]*1000. ...
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1answer
41 views

mosaic raster image non georeferenced

I have several jpeg2000 tiles non georeferenced and covering a certain area. I know in qgis you can mosaic image using the merge tool but I have done it only using georeferenced images, which is quite ...
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3answers
48 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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0answers
21 views

Translate old QGIS (2.2) Sextante model to newer version

Hey there (I guess Victor :-)) I really like the processing toolbox and have realized several models. I also developed some bigger models in QGIS 2.2 / with the former processing toolbox. Since the ...
2
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2answers
74 views

Projecting shapefile with unknown CRS to WGS84 using QGIS?

I've tried setting QGIS to on the fly, changing the layer settings, nothing. I'm at a lost cause. Although I am not a GIS professional. ...
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2answers
42 views

Getting attribute table from WFS data source

I am attempting to get some WFS 2.0 INSPIRE data from the Finnish meteorological institute into a table format of some kind. Is there any software which can easily grab the attribute data for the WFS ...
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0answers
15 views

Creating ROIS in Semi Automatic Classification pluggin Qgis

I am trying to classify a Landsat 8 image using the semi-automatic classification plugin in QGIS 2.6. When trying to define ROIS, I select a pixel of of interest, but the polygon is created ...
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1answer
22 views

Labeling only line vertices in QGIS?

I want to only put labels on the vertices of the polylines. I can use the data defined features to place a label at specific points, but not at multiple specific points. Is it possible to label only ...
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1answer
13 views

WMS Server scale problem?

I'm new to the environment QGIS, and my question and problem is when changing a layer coming from http://ide.cime.es/menorca/wms/base_referencia/ I want to load the 1-> 86 layer and at first ...
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1answer
25 views

Render or display only the boundary of a vector layer containing thousands of polygons

This might be a very basic question but my lack of experience makes it really hard to answer. To have a cleaner map to print I want to display only the boundary of a layer composed of more than ...
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0answers
82 views

Connecting Problem: ODBC versus ESRI Personal Geodatabase (*.mdb)

I try over 2 days to connect an ESRI Personal Geodatabase with QGIS 2.8.1 Here is my testing report. Testing environment: Windows 7 64-bit; MS Office 32-bit; QGIS 32-Bit 1. Step: Creating an ...
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0answers
24 views

C++ QGIS Conditional Label Colouring

I am using QGIS and C++. When I create a layer of polygons with labels in the center I am able to use a RuleBasedRenderer to control the background colour of the polygon. How do I similarly control ...
2
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0answers
23 views

Calculating area with Europe Albers Equal Area in QGIS [closed]

I am trying to calculate the area for a number of polygons in EPSG:102013, having changed it from EPSG:3857. When using the field calculator $area, the entire column was returned as nan. Has the ...
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1answer
35 views

QGIS - some edit feature options disabled in vector layer [closed]

I created a new vector layer in QGIS, saving as I went along and then I saved the project and logged out. When I went back into the project, I wanted to add some more features to the same layer, so ...
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0answers
26 views

GRASS in QGIS: Problem with creating isolines from points

I'm quite new with GIS and hope, anybody can help me here: I try to create isolines from service points by using GRASS in QGIS 2.8.2. After connecting the road network (based on OSM data) with 45 ...
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1answer
44 views

QGIS WGS84 issues

I potentially have a problem with my QGIS project, where I am attempting to digitise a relatively small map, and part of the project requires a calculation of the area of each of the parcels of land ...
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0answers
19 views

QGIS interface very slow on OSX

I'm running QGIS version 2.8.1-Wien QGIS code revision Compiled against Qt 4.8.6 Running against Qt 4.8.6 Compiled against GDAL/OGR 1.11.2 Running against GDAL/OGR 1.11.2 Compiled against ...
2
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1answer
80 views

How to create a plugin GUI for QGIS 2.8.2?

I create a pluging with the pluging builder in Qgis 2.8.2. I went to the folder of my pluging : C:\OSGeo4W64\apps\qgis\python\plugins\yu in order to visualize al the files that the pluging builder ...
1
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1answer
50 views

How to calculate raster statistics for each band in qgis

i need to calculate raster statistics for RGBN (4 channels, multiband image) rasters in QGIS. In Arcgis if you use "calculate statistics" in Arcatalog, statistics are calculated for every image band. ...
0
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1answer
34 views

Import georeferenced dwg-files to SketchUP

I have a georeferenced dwg-file in a national projection and want to import it into SketchUp pro 2015 without loosing the georeference. My workflow so far was to import it into QGIS, check it's ...
1
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1answer
32 views

How to delete char in table attribute in QGIS 2.6.1

I need to label many items but in the table attribute field there are some char (#F) for every item that I have to delete. The length of the description are not always the same. I create a new field ...
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0answers
36 views

Installing Orfeo toolbox for QGIS?

I installed QGIS through OSGeo4W 64 bit version in Windows 8. QGIS installed correctly, but I cannot add the Orfeo Toolbox. Any suggestions?
1
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1answer
36 views

How to extract and save polygons by attribute in QGIS?

I have a shapefile layer from a vegetation mapping project with 417 polygons that represent 21 different vegetation classes. These are stored in a single column called 'type'. I want to break the ...
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0answers
37 views

How to clip a big shapefile from another shapefile's extent

I am working on mangroves in Sundarbans (Bangladesh / India), using Landsat pictures. I need to equalize them in reflectance, before classification, for the evolution of the biomass in this region. I ...
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2answers
23 views

Pacific NW Projection Issues

The basic issue is that I have shapefiles saved in WGS84/Pseudo Mercator (EPSG: 3857) and some DEM data saved in NAD83/UTM Zone 10N (ESPG: 26910), but can't get them to line up. I'm using QGIS and ...
1
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1answer
50 views

Is there a way to export the style, along with a shapefile, to a kml in QGIS?

I see there were plugins in the past that may have done this such as qgis2kml and qgis2google, but they no longer exist.
1
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1answer
21 views

Displaying trailing zeros to right of decimal in label using QGIS?

is there a way I can get zeros to show up in my label when they come to the right of a decimal in a number such a s 270.00? I'm trying to display two decimals in all my numerical labels, but QGIS ...
3
votes
1answer
43 views

Add comma to number labels, multiple records in attribute table

A QGIS question: How can I insert commas in 4 digit numbers in an attribute table that has multiple records, with some numbers that are only in the hundreds? It's for an animation so multiple labels ...
0
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0answers
18 views

Python Error when I start Qgis

Thank you for the comment for this post: QGIS 2.8 starts with an error and I am not able to run Python console I have run yum search yum search qtwebkit and I got it that is installed. ...
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0answers
16 views

QGIS and QT library- code compilation problem [closed]

So, I am trying to workout an GIS standalone application using QGIS and QT C++ Libraries on linux(ubuntu 15.04). I am following this tutorial: https://github.com/qgis/QGIS-Code-Examples Taking the ...
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1answer
116 views

Connect to an ESRI Personal Geodatabase (*.mdb)

My environment: Windows 7 Professional: Service Pack 1 64-Bit QGIS: QGIS-Version: 2.8.2-Wien 32-Bit Microsoft Office 2010 Professional: 32-bit I want to connect an ESRI Personal Geodatabase ...
2
votes
3answers
68 views

An Overpass query for OSM ways; both part of a relation and also a specific tag?

How do I construct an Overpass query to find data on Openstreetmap which is both part of a relation and has itself a specific attribute? Specifically: I'm wanting to find sections of cycle route (in ...
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0answers
30 views

Merge multiple buffers [duplicate]

Is there a possibility to merge multiple buffers into one single buffer? Illustration: I would like the green buffer to be of one single piece.
1
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1answer
26 views

Different values after clipping

I have a satellite image from Landsat TM. I want to clip my area so i created a polygon and thru Qgis --> raster clipper I am trying to clip my area of interest. I noticed that the results have ...