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

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261 views

How to populate a combobox with layers in TOC?

I am developing a plugin, and I want user to select one of the loaded layers from a combobox. I've already coded this much: self.dlg.show() layerlist = [] self.dlg.ui.layerCombo.clear() # ...
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1answer
93 views

How can I use pyqgis to automate a series of field calculations?

I've got a shapefile with about 30 fields that I'll need to update from time to time by importing a CSV with new data, joining it to the shapefile, and using the field calculator to carry the new ...
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1answer
441 views

How to indicate flow of a watershed feature?

While tracing and digitizing rivers, streams, rivulets, etc., is it possible to indicate the direction/flow in the shapefile on QGIS? I'd like to avoid using map labels. Ideally, when done tracing, I ...
3
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1answer
65 views

Why are there no more error messages after importing QGIS modules into python?

I have a problem when writing python code whilst including the qgis modules. As can be seen below, when I usually call a variable that does not exist (for example), I receive the usual error message. ...
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1answer
90 views

Why can't I open a kml layer?

I thought that I could open kml layer like a normal vector layer but it doesn't work (it says "invalid datasource"). How can I open a kml layer in QGIS? Or how can I open it anyway, I never worked ith ...
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1answer
141 views

reproject vector layer with pyqgis with new CRS does not worl

In QGIS I am running a script in th python toolbar to export all visible vector layers to a GEOJSON with this snippet: canvas = qgis.utils.iface.mapCanvas() allLayers = canvas.layers() for i in ...
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1answer
139 views

Why can't I open QGIS projects via windows explorer?

We have upgraded from QGis 1.8 to QGis 2.2. Qgis 2.2 is first installed, then 1.8 removed. Since then it is impossible to open .qgs-projects directly from windows explorer. We have checked explorer, ...
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1answer
53 views

QGIS hides few graduated points after reopening project

I have a strange problem in QGIS 2.2 (problem is also present in QGIS 2.1). When I add a point (shapefile) layer, apply graduated style and change point size, everything looks fine. Then I save ...
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1answer
53 views

QgsFeatureList features as QStrings

I am catching the selectionChanged signal and passing the selected layer to the registered method. Once here, I want to know the features that were selected. I do this with a call to ...
8
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1answer
283 views

How to do Manhattan Voronoi on QGIS?

I've spending last two weeks trying to discover how to do a Manhattan Voronoi on QGIS. For the difference between Manhattan Voronoi and "normal" Euclidean Voronoi, please check this link Can someone ...
3
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3answers
238 views

QGIS Mosaicing with null values in images

I have a set of landuse landcover data which needs to be mosaiced. Whenever i try using QGIS Raster>miscellenous>merge tool. giving no datavalue as '0', it returns either (A) ' Traceback (most ...
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0answers
128 views

Programmatically modify layer datasource on project save event (QGIS)

I have a QGIS plugin which allows users to add WFS/WMS layers to the map. I would like to be able to scramble the user ID part (token) of the uri when the project is saved/closed and then use my own ...
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2answers
326 views

How does one export the list of stored WMS-servers in QGis?

Could anyone point me as to where QGis stores the list of WMS-servers you added? I have built a fairly large list of WMS-server on one computer, but the QGis-project file which gets accessed by my ...
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0answers
117 views

QGIS custom form and autocompleted data entering with “validation check”

In Qt-Designer I created a custom form where I can choose serveral species names in two different combo boxes. This combo boxes are linked via "value relation" to the accordant non spatial tables ...
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0answers
237 views

length and width of polygon

how can i find polygon's length and width in Qgis(regular polygon and irregular polygon)? i have area and perimeter but possible to have length and width ?.
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3answers
504 views

Merge images first, or georeference first?

I'm wanting to georeference and vectorise some features from scans of the OS 1896 Town Plans that I have purchased from the NLS (http://maps.nls.uk/os/london-1890s/info.html). The scans provided are ...
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2answers
56 views

Where are QGIS application setting file(s) stored?

I have some application settings (Windows/QGIS v2.0) that I would like to pass to other users (such as those settings defined under Settings menu>Options>Rendering tab). In ArcGIS they are stored in ...
2
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0answers
153 views

Is there a decent algorithm in QGIS Process Modeller to create a grid?

I am using Process Modeller to automate merging several vector layers and then creating a grid to cover the extent of the merged layer. There are functions which already exist which are not listed in ...
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1answer
173 views

QGIS: graphical-modeler to calculate area of polygons

I'm trying to calculate the area of polygons using the field-calculator in QGIS (2.0.1). If I do this manualy it works fine, but if I do this using the graphical-modeler I get NULL as area for every ...
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0answers
42 views

How can I see the overlay of two features (point & polygon)?

I am trying to open two digitized layers, one containing points in a region and second which I have downloaded separately for the region as polygon layer. I would like to overlay two of these layers ...
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1answer
57 views

How to use QGIS field calculator to delete style code?

I am struggling with following issue: How to delete style code before id codes x.x.xx.. and the }s in the end? Examples below. Any help appreciated! {\fArial|b1|i0|c0|p34;A.B.11} ...
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2answers
387 views

How to make multiple qgis mapbook pages in 1 pdf?

Is it possible to export a mapbook in QGIS 2 with multiple pages all in one PDF? Thanks
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2answers
682 views

How to add Georeferenced PDF as layer to QGIS 2.0?

I have some georeferenced pdf's that I would like to open in QGIS. I have read that GDAL version 1.8 and higher will support pdf, and I have GDAL 1.10 installed with QGIS 2.0 on Windows 7, but when I ...
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1answer
166 views

Spatialite Table Difference in QGIS

I am see differences between tables when I view them in spatialite-gui and in QGIS. I have created a table, added columns, and updated the columns in spatialite-gui. Within spatialite-gui I can view ...
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0answers
144 views

Error: .asc is not a supported raster data source

I am new using QGIS and struggling with this error "...... .asc is not a supported raster data source" when trying to add a ."asc" file as a raster. I downloaded the files from ...
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1answer
124 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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0answers
56 views

Error 14: Could not open CRS database

I am using Python Console and loading a Vector Layer using python commands. When the layer is added, QGIS first asks for the CRS to use, but I don't have all the CRS listed out to select the Reference ...
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1answer
186 views

extract shapefile attributes from raster colors

I have two layers: a shapefile with states and counties (shp) a raster file (with colors and some text and borders, but not a perfect map) (tiff) I want to use the colors in the raster file to ...
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0answers
67 views

HTML Annotations

I am trying to insert html annotations into my map. I was hoping they would be interactive and pop up as you move over or click on a feature, but they don't seem to function this way (that I can ...
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2answers
1k views

QGIS Select by Expression

A basic QGIS 2.2.0-Valmiera, Select By Expression - Field Calculator question. Introduction I am a geologist searching through a geological database (see attached figure). I have a shape file and ...
7
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2answers
589 views

Unable to get python-qgis-common on Kubuntu 14.04

just upgraded my Kubuntu from 13.10 to 14.04 LTS and lost all plugins. Found out that "python-qgis-common" is not installed. Tried to install it but was told that it depends on "sip-api-10.1" which ...
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1answer
598 views

Split a line feature using nearby points

I have a line shapefile and a point shapefile, and the line has its own segments and its attribute table, the point shapefile has points near the line above, not on it and the close ...
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1answer
346 views

QGIS crash Ubuntu 14.04

Encountering a crash when requesting QGIS 2.2 to access data on desktop machine. Running Ubuntu 14.04 LTS. $ qgis Warning: loading of qt translation failed [/usr/share/qt4/translations/qt_en_AU] ...
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1answer
141 views

Building with MinGW 4.8

I'm working on a project where we would like to add QGIS features to an existing Qt application. The Qt application has been built with Qt5.2.1 using MinGW 4.8 and thus I think I need to build QGIS ...
0
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1answer
859 views

QGIS 2.2: GDAL Grid (Interpolation) Error

As much as i understand Raster -> Analysis -> Raster (Interpolation) can provide me with a terrain file out of a shape file with a Z coordinate. I select the input and output file and a Z field. It ...
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0answers
125 views

back up of qgis file

Can we recover a previously saved version of qgis file? For example: I have saved my qgis file about an hour but I need the yesterday's back up of qgis file. The file which does contain today's saved ...
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4answers
524 views

How do I use QGIS 2.2 to plot some locations on a map (of the US by zip code)?

I am a newbie to QGIS. I just installed it on my MAC Airbook with Mavericks. How do I simply plot a few locations on a map of the US? All of the tutorials I can find on the web are for older ...
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1answer
87 views

Excel Nad83 table to gpx-Total noob

I have some waypoint locations that I have entered into a spread sheet in Nad83 the format of table looks like this NAME, -, -, UTM ZONE, Easting, Northing, -, Comment 1184236, 1, CP, 15, 451596, ...
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1answer
169 views

Including two different maps in one QGIS Print Composer

How do I use print composer in QGIS 2.0.1 to produce a final product with two different maps on the same sheet? I can't figure out how to use the 'add a map' button to add anything other than a ...
2
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1answer
421 views

How to get Drainage Divide and Streams from DTM

Does anyone know how you can get a map like this attached, having the digital terrain model? I'm sorry, but I do not know what is the exact technical term in English for them. I hope you understand ...
0
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1answer
82 views

Why do the SHP lines in QGIS Android look jagged (very simplified)?

I use QGIS for more than five years. I'm trying to make my way with QGIS Android for a while now. For some time I experience the following problem with the "nightly build" 2.0.1-Dufour: the SHP lines ...
2
votes
1answer
660 views

Why does clipping a line layer using a polygon result in an empty shapefile?

I am using QGIS 2.2.0 and want to clip a line layer (roads) so that only those inside a polygon are shown. When I do this using Vector->Geoprocessing Tools->Clip I only get an empty shapefile as an ...
3
votes
1answer
247 views

Programmatically change layer position in the table of contents (QGIS)

I am trying move/position a layer to the bottom of the TOC by using addTopLevelItem on all other layers. I unsure how to reference the layers as QTreeWidgetItem's. def bg_bottom_level_item(self): ...
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0answers
126 views

MODIS images set CRS and reproject

I am developing a plugin which reads MODIS images, and I know that MODIS images are in sinusoidal projection and I need to set that CRS and project the image to WGS84 (epsg 4326) in python. I search ...
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1answer
272 views

QGIS 2.2 - expression string builder to ignore NULL values

Simply put, I would like to create a rule-based filter whereby you add 2 columns together and you get a certain colour as a result. However, some fields in Column_1 may be NULL and those exact same ...
3
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1answer
95 views

loss of attribute data when copying between layers

I am trying to copy points from one layer to another in QGIS 2.2 The problem I get is that all the attribute data from the copied points is missing when copied onto the new layer, the columns show ...
4
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2answers
163 views

Read an INSPIRE GML in QGIS2.0 : gml:xlink resolving

I'm trying to read an INSPIRE GML, which contains internal and external links between the elements. I saw on the GDAL site that we can set environment variable in order to load this link in QGIS ...
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1answer
83 views

In QGIS are there similare construction tools to ArcGIS?

For a project we are using ArcGIS to reshape autogenerated features. For that we often use the construction tools polygon, rectangel, circle, etc in ArcGIS. The right angle is also an often used tool. ...
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1answer
550 views

How to go with…somewhat complex geological maps in QGIS?

Just a follow-up to this question QGIS: Line to polygon conversion. Not sure do i have to continue there itself... We are currently digitizing a geological map...which has 36 features in total. Some ...
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4answers
540 views

Needed shape file for Australia and New zealand

I was trying to find a shape file which has Australia and New zealand together(states) so that i could convert to jvectormap for ANZ. where i can find it?