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

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3
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116 views

Performance difference between focal statistics (ArcGIS) and neighbor (GRAS or QGIS)

I tested minimum, maximum, and average neighbor (circle radius = 161 pixel) using ArcGIS, GRASS and QGIS: ArcGIS (10.1): it takes only one minute GRASS (6.4.3): it takes 123 minutes for every output ...
3
votes
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60 views

QGIS atlas generation - batch process for many atlases

I have many different QGIS projects, each one is designed to create one particular atlas or map book in pdf format (one different book per every QGIS project). Month by month I must actualize each ...
3
votes
0answers
164 views

qgis 2.8.1 - processing gdal 1.11.2 error (mac, 10.10.2)

i've just recently installed qgis 2.8.1 on my mac. including all relevant packages from kyngchaos - i.e. GDAL Complete 1.11 framework package, Matplotlib Python module, numpy - and updated python to ...
3
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103 views

QGIS 2.8 PrintComposer, no coordinates shown

I tested under MacOS 10.10.3 and 10.9.5 now: In the QGIS v2.8 Print Composer I don´t get coordinates shown when I want to create a map sheet and activate "Draw coordinates". I can do all settings ...
3
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0answers
32 views

Saving a calibrated route in QGIS for “future” use

Can a Calibrated Vector (after using LRS) be saved with M values, so that the file does not have to be calibrated every time is used? We're currently working on State road data, and it has many ...
3
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259 views

Why are OGR (MySQL / PostGIS) connections extremely slow in QGIS 2.0 - 2.8 (when compared to QGIS 1.8)?

In our project we have been using QGIS 1.8 Lisboa with a MySQL database placed on a server accessed via local network since two years. Everything is working fine and quick. The vector layers can be ...
3
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140 views

Why does field calculator compute area in square meters?

I am using EPSG:102748, and have set my Settings/Option preferred measurement units to ft. My CRS is NAD_1983_StatePlane_Washington_North_FIPS_4601_Feet, and when I use the measure tool, it returns ...
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35 views

How to display features only if labels are displayed?

In my maps there are several point layers, and each layer has a different labelling rule and priority. Sometime the point density is too high and the labelling engine is not displaying some labels, ...
3
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0answers
71 views

QGIS algorithms do not work on copies of shapefiles?

I'm using QGIS 2.6.0. I'm trying to run various algorithms such as "SAGA/Shapes-points/remove duplicates" & "SAGA/Shapes-Grid/Add grid values to points" through the sextant toolbox. When I run ...
3
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374 views

Connect to QGIS 2.6 Python Plugin function via button on custom feature form

I am trying to connect to a QGIS 2.6 Python plugin function via a custom feature form button. On my feature form, I'm attempting to do a few things : enable the updateButton only if the ...
3
votes
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111 views

How to calculate areas in raster files

I got three files. The first is a shape file for country boundaries and the second and third are two raster files with the global land covers for 2005 and 2009. I'm thus encharged to calculate the ...
3
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72 views

Create buffer based on polyline without line end caps and without dissolving the created polygons in QGis

I have a projected line layer (Shapefile) in QGIS. For every line segment I want to create a polygon without line end caps. The resulting polygone should not be dissolved to a single one. I tried ...
3
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0answers
208 views

SAGA is not working within sextante (QGIS processing installed in Ubuntu)

Recently i decided to start working in Ubuntu (version 14.04). My first step was to add the ubuntugis-unestable repository, and then proceed to install SAGA, GRASS, OTB, QGIS and the bindings between ...
3
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270 views

why in my processing of qgis not exist the module Catchment area (Parallel)?

I have qgis 2.4.0 chugiak and have install processing but in the box of tools not exist the module catchment area (parallel), how to install this module? thank you !!!!
3
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0answers
88 views

Merge Raster Layer Specific Order in Graphic Modeler

I'm using the Graphic Modeler/Processing Modeler to automate a process. The last step in this process is Merging three different Raster Layers. I'm using the "Merge Raster Layers" from Saga 2.0.8. ...
3
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79 views

Frontal Detection of sst & Chlorophyll image

I am working on sea surface temperature satellite images and looking for delineating gradients in open source on the basis of temperature. Is there any tool like Cayula and Cornillon front detection ...
3
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0answers
653 views

How to install QGIS with ECW support on Mac?

I bought a imac recently and I tried to install qgis: without success! It is not possible to read the raster files. I installed GDAL ECW plugin, but it is necessary to copy and paste another file ...
3
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115 views

Preserve datatypes when using SQLite and QGIS

Following Nathan's SpatiaLite/DBManager solution in this answer, I find that once the layer is loaded from DB Manager into QGIS (2.6.1), any calculated fields are appearing as text values instead of ...
3
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391 views

How to save geopackage gpkg file with QGIS

I read about the new geopackage file which shall have the potential to be the shapefile of the future. But i can't find a way to save a file in QGIS as gpkg. In ArcGIS it might be possible. I would ...
3
votes
0answers
81 views

Why do each of my buffer-polygons have different areas

I`m using Qgis 2.2 and 2.4 and loaded a wms-map using the coordinate system ERTS89 UTM 32N. I set 8 points (all in on shp-fileand in UTM 32N) on various locations on the map. After that i created a ...
3
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328 views

QGIS 2.6 Brighton - Graduated Symbols

I can't get graduated symbols to show in QGIS 2.6. This is what I have done. I have two fields of type integer, saved as a shape file which I have tried to import as a shape file and as a secondary ...
3
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35 views

QGIS isn't displaying dates in the attribute table

I have a QGIS project that links to data in a Postgres database. For some reason, QGIS is not displaying any data in date fields. The date fields appear to be fine in Postgres and I have performed ...
3
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85 views

How to export two related layers to KML with multigeometry using QGIS?

From QGIS, I would like to create a KML file, for GoogleEarth, which contains multigeometry in that KML file. By example: consider two layers in QGIS -- the first layer contains polygons, and the ...
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52 views

QGIS Cross Section Profile Distance using Ellipsoid?

I am working with QGIS 1.8 and 2.6 and can't get any of the Cross Section Profile tools to provide the ellipsoid ("proper") distances. All the distances use geographic coordinates which are too ...
3
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22 views

Action: Move pointfeature to other layer - Point becomes Multipoint

I'm trying to write an action that moves a pointfeature from one layer to another. It works fine until i try to save the layer with the new feature on. He says he can't save a MULTIPOINT to a ...
3
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54 views

Editing Cursor for GPS live tracking in QGIS 2.4

I am interested in using QGIS 2.4 for vessel navigation due to its ability to display NOAA vector charts or BSB's as well as user created shapefiles. I currently oversee a project that requires ...
3
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50 views

Generate a series of ellipses on a line

I am trying to create a series of ellipses (mocked up in green below) of defined dimensions along a line. I have got as far as generating regularly spaced points along the line that are attributed ...
3
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293 views

How to convert length in Decimal degrees to meters programmatically?

I'm new to qgis and I want to find the length of some roads in a map. So I used the following code, from shapely.wkb import loads def getLength(): layer = ...
3
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0answers
189 views

Does QGIS work with Anaconda?

I am trying to get QGIS to work with the Anaconda distribution of Python but I do not know how to get this to work. In one of the answers it was mentioned that QGIS does not work with Anaconda and I ...
3
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0answers
152 views

How complete are the Fusion tools in QGIS?

How complete are the Fusion tools in QGIS? I have them installed and (vaguely) working, but there are only about ten of them. Is the idea of having just a few tools available, that one can use ...
3
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178 views

Command line tools to generate elevation profile from DEM + GPX/GeoJSON

I'm looking to generate elevation profiles from a number of GPX traces (which I also have GeoJSON conversions of). I have 20m resolution DEMs of the area, in GeoTIFF format. Ultimately I want to ...
3
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252 views

Problem with print composer when exporting a map with Google Maps Plugin in the background

Whenever I try to export a map with the Google Maps plugin in the background, it exports but just exports to a blank document. When I turn the Plugin off so it is not in the background, it prints ...
3
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0answers
156 views

Unable to add shapefiles via drag and drop - QGIS 2.4 OSx

I have a clean install of OSx Yosemite Beta 5, with homebrew install of QGIS 2.4 and all its basic dependencies. -QGIS version 2.4.0-Chugiak -QGIS code revision exported -Compiled against ...
3
votes
0answers
158 views

How to snap and move circles by the center?

I have a point layer, and a polygon layer with buffers of a given radius around each point. I need to move points, and check that each buffer is not above forbidden land/plots. In autocad, you can ...
3
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217 views

Batch export to shapefile by attribute field in QGIS

I have a project in QGIS where I am creating a map of plants over a large area. I want to take the "Genus" field (of which there are 100 hundred values) and essentially create 100 shapefiles based on ...
3
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44 views

QGIS “Fill Ring” tool error on SpatiaLite DB?

I´m try Fill Ring tool on a SpatiaLite DB and I get a error on the Primary Key. The Primary Key is integer auto increment. When I insert the ring and try to save editing I receive error message ...
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502 views

Can I export the RGB values from an ArcGIS layer symbology?

I've got a point layer in ArcGIS that has 100 specific color codes based on the name of the store. I'm trying to export the RGB values for these colors (along with the name value it's tied to) so I ...
3
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0answers
81 views

Resampling air temperature gridded data to sub-grid resolution

I'd like to obtain a 30-m resolution gridded dataset of air temperature from the ~1km gridded data of WorldClim, of Hijmans et al., 2005) for a mountainous region. The easiest procedure (I thought ...
3
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0answers
80 views

Automatic generation of equidistant points inside a polygon in QGIS?

I'm trying to find a way to generate a layer of points inside a given polygon of, for instance, 100 m x 600 m. Every points must be distant from the others and from the polygon borders of (e.g.) at ...
3
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0answers
68 views

Overriding the QGIS Feature Dialog

We are developing a QGIS plugin and would like to override the QGIS Feature Edit Form with our own Dialog. Have explored using setEditForm and setEditFormInit, but the init process appears to want to ...
3
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0answers
58 views

QGIS - Auto-Update Color-Ramp to Current Display Extent

When displaying raster files in Qgis with the color-ramp stretched to the min/max values of the current display extent, the min/max values don't update automatically when zooming or panning to a new ...
3
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0answers
83 views

Is there a limitation on the numbers of layers that can be displayed in QGIS?

I have been looking for an answer to this question for the last several weeks, so hope that someone here has encountered the same issue and has a viable solution to my problem. I am currently using ...
3
votes
0answers
146 views

Create vector grid from canvas using script

I've modified "Hex grid from layer bounds" script to my need. Just added cellsizex and cellsizey. Changed the hexagonal - 3 to "1" to make it as a square grid. Is it possible to include an option to ...
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0answers
205 views

ISOdata classifier in QGIS?

Is there a function that produces an ISODATA unsupervised classification in QGIS? The only unsupervised classification function I can find is a KMeans.
3
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0answers
106 views

Connecting QGIS 2.x to Firebird Database via ODBC?

I tried to connect a Firebird Database in QGIS 2.2 and 2.4 via ODBC to a database and get following error message: Unable to initialize ODBC connection to DSN for SYSDBA/masterkey@Akdees ...
3
votes
0answers
780 views

QGIS 2.4.0 Mac Yosemite compatibility

I just upgraded to the Beta 2 version of MacOS 10.10 ("Yosemite"). I'm getting an error when I try to "drag and drop" shape files into QGIS. I'm running QGIS 2.4.0, GDAL 1.11, and MATPLOTLIB 1.3.1. ...
3
votes
0answers
255 views

How to calculate percentages using QGIS field calculator expression?

I am new to QGIS. I am wanting to calculate a field using other fields and some operators. Here is my expression: case When "RVM_CAT" = 'B' OR "RVM_CAT" = 'C' Then ("PC1" /100) * "RE_ha" When ...
3
votes
0answers
194 views

Startup python script to re-join layers

In QGIS 2.2, there is a bug which involves using the JOINS properties on a vector layer (that is already being joined with several other vector layers) whereby the attributes are not fully loaded. ...
3
votes
0answers
316 views

Creating one DEM from multiple ASC files

I am struggling with this several days and now its time to ask how to do it in QGIS. I have very detailed 27 ASC grid files with overall size of 9 GB created from 1m contours of large area (600 m2). ...
3
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76 views

Option for 360 degree movie embedded in Open Source GIS software?

Is there any Open Source GIS software available to embed 360 degree movies with the map? For a COTS example, there is the Active Link Vision (ALV) extension for ArcGIS from IWANE.