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

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14 views

How can I shift raster layer for making cloud-shadow mask?

I want to make cloud shadow mask in QGIS. I have raster cloud mask and I have to shift it by X,Y coordinates. Is there any easy solution? Many thanks, Helena
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1answer
52 views

Why don't all the attributes in the SQL query appear in table?

I have an SQL query that works fine in the DB Manager but when I load the table as a layer one column does not get loaded. The different thing about this column is that it is static -- text generated ...
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2answers
78 views

How to use OS Terrain 50 in QGIS

I am new to GIS and I wish to perform view shed analysis of wind turbines from a DEM. I have downloaded OS Terrain 50 and the data is contained within numerous zipped folders. I am using a Mac with ...
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0answers
29 views

Vector seems to be only a pixel of a raster after reprojection

I have the South America hydro1k data for slopes and I am trying to extract the data using point sampling tool with a grid in Brazil's map. My problem is that, even though vector and raster seem to ...
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0answers
29 views

Retrieve a point coordinates from map canvas using QGIS API

I'm trying to build a plugin that firstly captures the map coordinates. I have tried to adapt the map tool explained in this post: How to programatically check for a mouse click in QGIS The code I ...
2
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1answer
150 views

Wind Farm Viewshed Analysis

I am new to GIS and I want to run several view shed analysis operations for wind turbines located in the North of England I have installed QGIS and have the GRASS r.los plug in installed for line of ...
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2answers
100 views

Qgis server on Ubuntu Server 14.04: Permission denied

I'm trying to install and configure Qgis Server (2.0.1) on a virtual server with ubuntu 14.04, Apache 2.4.7. After trying to install normally, the server gave me 404 error, so I tried to add ...
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0answers
24 views

Memory layer or QgsVectorFileWriter Error?

Currently this excerpt of code will not save to file (as it is supposed to). The memory layer is visable and editable. Yet even when manually saving the layer, any priorly added features ...
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1answer
55 views

Open QGIS project on different computers

I have multiple QGIS projects that need to go to different computers. I put all the files on a USB and loaded it under "Documents" on the other computers like it is saved on my own computer. ...
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0answers
16 views

splitting polygons by semi-automated classified raster and into multipolygons

I am studying glaciers. Most of them in my case are partly covered by debris (i.g rocks) and partly not. So I ran an automatic classification to recognize these two type of coverages and produced a ...
3
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1answer
77 views

QGIS 2.4 Not Importing ExtendedData from Self-Exported KML

I've been scouring the internet for the past few hours, and I just can't seem to figure it out! Is it just me? I am using Quantum GIS 2.4.0-Chugiak. Here are my simple steps: 1) I create a new ...
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1answer
43 views

Memory Vector Layer Corrupted?

I was working with a large data set that had data for roads, rivers, railways, etc. all together so I decided to break the different data out so I could label it differently on the map and check each ...
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0answers
29 views

Joining polygons with same boundaries

Sorry if my question feel stupid but I'm a new QGIS 2.4 user. My shape is composed of 7 polygons which are supposed to be adjacent (ie sharing sharing same nodes). Would like to join the polygons by ...
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0answers
10 views

Proper updating of new memory layer geometry?

Current workflow for a toolbar button: -create memory layer -save memory layer to shapefile Then the user uses the built-in QGIS tools to add geometry and finally saves changes via the auto prompt ...
2
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2answers
40 views

How to color lat/lon points in given RGB data?

I am using QGIS on a Mac. I am working with hydroacoustic data for mapping and interpreting the seafloor. Data are collected, processed and interpreted. The result is a txt file with Lat and Lon in ...
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0answers
21 views

How can I get WPS contour from only giving interval value to geoserver?

In my openlayers example I am giving all the values from where its starting. For example, with values like 540,570,600,630,660,690,720: here 540 is starting and 720 is ending, interval is 30. I got ...
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1answer
27 views

QgsMapCanvas.reresh() does not reload new wfs layer features, but panning does

I have a wfs layer loaded in a standalone QGIS app, which I am updating by running a database query on the view it is based on. The feature is added with no problems and I reload the layer with: # ...
6
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2answers
246 views

Versions of Python & QGIS for new user to both to install?

I have used GIS (very basic functions), but now want to be able to customize to my needs. My initial research leads me to believe that Python + QGIS is the way to go. I understand that there are ...
2
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2answers
55 views

How to change precision on a column in the attribute table without losing data?

I have data in an Excel-file that I want to join with a shapefile in my project. The Excel-file contains values like volumes. The Excel-file and the shapefile I want to join it with both contain the ...
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1answer
109 views

Simplifying Shapefile without risking Spatial Accuracy?

I am building a feature for a web application. Basically would use the ABS (Australian Business Statistics) data to render the regions on the Google Maps. I am able to implement the basic working ...
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1answer
17 views

QGIS, Multiple lines and wrap on character? [duplicate]

How to make wrap on characters in Labeling layer settings. I tried various solutions, but it works. Does anyone know how to do?
2
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1answer
27 views

QGIS - delete polys based on vector line layer - possible?

I have a layer of polygons and a layer of vector lines. I want to delete any poly that is touched/crossed/intersects a vector line. Is this possible? I have tried the Geoprocessing Tools. Looks ...
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1answer
32 views

I'm not able to save edited layer connected via PostGIS in QGIS

I have project and i was doing editing layers in QGIS. These layers are connected in QGIS via PostGIS. 1 layer of the 4 layers was saved correctly but other layers gave me error message. Error ...
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0answers
29 views

Keep leading zeros when importing .csv into QGIS?

I'm having issues getting QGIS to retain leading zeros when I import a .csv file. I have zip codes I am trying to read in and I need the leading zeros. I am not super familiar with GIS, so please ...
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0answers
16 views

QGIS2.4.0: Cannot import qgis module in python “from qgis._core import * \n DLL Load Error”

Having some trouble importing qgis into python. I'm very new to python so it could be a simple mistake. The path seems to be correct. It gets this far: File "<stdin>", line 1, in ...
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0answers
54 views

Copy parts from several attribute tables in shapefiles?

I have several shapefiles from which I wish to take parts from their attributes tables to make a new attributes table. Is this possible without destroying the original attributes table? I have ...
3
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1answer
32 views

QGIS: Plot a layer given with Longitudes [0 360] to [-180 180]

I have a world map in correct Longitudes from -180° to 180°. Additionally, I have a shapefile of data from South America, which shows at 290° instead of -70°. How can I reproject it using QGIS?
3
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1answer
37 views

Changing attribute values in a memory layer

I'm trying to change attribute values in a memory layer. My memory layer is defined in this way: pro.addAttributes([QgsField("nom", QVariant.String), QgsField("valeur", QVariant.Int)]) I made ...
2
votes
1answer
131 views

Highest DEM pixel in polygon

I'm working with QGIS and have a big DEM raster layer with height information and a vector layer with many polygons, representing 1 x 1 degree tiles. Now I want to find for every polygon the highest ...
2
votes
1answer
54 views

Clip in QGIS 2.4.0 resulting in empty output files

I'm seeing the same problem to Clip or Intersection tool - QGIS giving empty files trying to use the Clip tool since upgrading to QGIS 2.4.0, but have not been able to fix the problem based on the ...
2
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1answer
14 views

QGIS raster clip error: Cutline not of polygon type

I have a raster file and want to clip it, but I'm getting this error: "ERROR: Cutline not of polygon type" what does this error mean and how can I resolve it?
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0answers
29 views

Vector layers without geometry in QGIS?

Using QGIS, I have set up a couple of automated layer additions via the toolbar. After adding geometry in each respective layer (point, lineString, polygon) and saving changes to the layers, the added ...
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0answers
60 views

Exporting spatialite view to shapefile from QGIS modifies the original data types

We have a spatialite .sqlite database where we have views which are nicely rendered by QGis, with all the symbols and everything!! There are integer fields on the view which are based on fields of ...
2
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1answer
51 views

Calculate EVI From Landsat 8 in QGIS [closed]

I have calculated atmospherically corrected reflectance values for Landsat 8. From that, I am getting correct values of NDVI in QGIS, but for EVI I am not getting the correct values. For some images ...
2
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0answers
21 views

Align & Sum Grids in Python

I have two grids. One, call it A, is 4320x2160 cells and spans the whole globe. The other, call it B is 8640x3432 and spans the circumference of the globe, but is clipped toward mid-latitudes. Both ...
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2answers
34 views

QGIS Convert Polygon M to polygon

I have been using Argis 10.1 and been able to convert polygon m to polygon shapefiles. I would like to do this with QGIS but I am having difficulty in finding the correct tool to do so. Please Help
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0answers
69 views

I cannot install QGIS 2.4 on my Windows 7, 64 bit machine

I am running Windows 7, 64 bit and cannot install QGIS 2.4 after several days of trying. I have also tried downloading 2.2 with no avail. I keep getting this error: The text of the error is: ...
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0answers
25 views

QGIS crashes when trying to display features form MySQL

I import shapefiles into MySQL using the following command: ogr2ogr -f MySQL MySQL:GIS,host=localhost,user=root,password=root /home/user/Public/myshape.shp -nln Shape_table -update -overwrite -lco ...
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votes
3answers
52 views

How to display a table with more than one geometry column in QGIS?

In PostGIS, it is possible to use addgeometrycolumn more than once on the same table. Example: I have one table "scenes" with many attributes, and 2 geometry columns: the_geom1 and the_geom2. select ...
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1answer
58 views

QGIS Relation Manager

I have a PostgreSQL database with a one-to-many relationship. Here is a reduced example: CREATE TABLE buildings.building ( objectid serial NOT NULL, building_no character varying(40) NOT NULL, ...
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2answers
56 views

QGis 2.4 - Python 2.7 PyQT4.Qtcore.QStringList Import failed

I receive an import error when trying to import QStringList from the Qgis Python console (or when loading a custom plugin). from PyQt4.QtCore import QStringList Traceback (most recent call last): ...
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1answer
19 views

How to set QGIS options in standalone pyqgis application

I have a standalone application which uses the QGS api to view and query map layers. One layer is a WMS-C layer which automatically caches tiles which is great. I want to also activate a setting which ...
2
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0answers
20 views

access point layer representation in qgis with pyqgis

I am exporting the style of a categorized point layer with qgis: unfortunately my code only extract the size of the symbol in the definition of the properties of the layer but not the ...
3
votes
3answers
212 views

How to export polygon coordinates to CSV (not WKT)?

I am new to QGIS, and I am now trying to export polygon coordinates from a shape file to a csv file, but so far all my attempts have failed. I have found numerous questions and answers about this, but ...
3
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0answers
34 views

How to export data from sql server into shapefile in the decimal format in QGIS 2.4?

The last couple of days, I have been working on exporting data from SQL to a shapefile in QGIS 2.4. While converting into a shapefile, the data type changes automatically from Float to Integer in the ...
3
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1answer
34 views

How can units be defined in QGIS for the Rasterize tool?

I am using QGIS 2.4 (Chugiak) via the kyngchaos build for OS-X. My question is--when using the Rasterize tool to convert a point vector layer to a raster and using the "Raster resolution in map units ...
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1answer
25 views

How to add dashed line in QGIS print composer

I want to display two maps in the print composer: a main one, and another showing a zoomed in section of the main map. I've drawn a rectangle over the original region and want to add two dashed lines ...
2
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1answer
51 views

How to find and replace a singe word in a string?

How do i find and replace a single word of a string? e.g. Calle Iparraguirre to Iparraguirre I've tried: replace( 'Calle\\s', 'Calle\\s', '') replace( "name",'calle','') and all combinations ...
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1answer
36 views

Coordinate System changes after reprojection

I have changed the projections of some Natural Earth Shapefile to "WGS 84/Pseduo Mercator", that works fine (after cutting out the artic), but now the co ordinates of the shapefile are all out of ...
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0answers
27 views

How to set a defined distance between nodes to digitize in qgis?

Using QGIS (by now I have the 2.4 version) I would like to set some parameter (I don't know if such exists) that would impose a definite or maximal distance between nodes when digitizing a polyline or ...