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

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2answers
97 views

QGIS Connection PostGIS and shapefile

I'm working on QGIS with a database created in PostGIS and a shapefile. Inside the database, I have geometry type data about location of some points, instead on the shapefile there some selected ...
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1answer
280 views

JPEG base map doesn't match shapefile locations

Relative Newbie Question: I have Civil War earthworks tied to the State Plane Coordinate system with a jpeg of the terrain as a 100k scale USGS Quad of the area that is not georeferenced. When I work ...
1
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1answer
93 views

Overlap or intersect two choropleth [closed]

I have two choropleth of the same area but with different concentration data and I need to overlap them. My aim is to highlight the areas of intersection between the points with the highest ...
1
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2answers
421 views

How to calculate distance in meter between QgsPoint objects in PyQgis?

I tried to calculate distance between QgsPoint objects in qgis, i used QgsPoint StartPoint.sqrDist(EndPoint). but i don't find an expected result, i also tried import math ...
1
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1answer
135 views

How to remove thin lines and small points from qgis raster

I want to digitize the roads of a raster map to vector format using QGIS and GDAL preferably. By using the Raster Calculator I have been able to extract the roads and contour-lines from the raster to ...
1
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1answer
669 views

How do I use 'model builder' in QGIS 2.2?

I am trying to learn how to use the 'model builder' in QGIS 2.2. I have used model builder in ArcGIS, but I don't understand how to do it in QGIS 2.2? What I want to do is to make buffers, clip ...
0
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1answer
116 views

How can I create an animation with raster data in qgis?

I have 4 raster images showing different coniditions of air flow distribution at different times. I'd like to create an animation to show the change from image 1 to image 4. How can I do this? I tried ...
2
votes
2answers
179 views

Converted GPX file has null values in open attributes

I'm an absolute newbie but I think I'm doing this right. I've got a bunch of .fit files from my garmin. I can use GPSBabel to manually convert these to GPX XML and the map looks fine after the ...
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1answer
260 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
92 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 ...
1
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1answer
437 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
votes
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. ...
0
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1answer
89 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 ...
1
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1answer
140 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
138 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, ...
1
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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
votes
1answer
282 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
237 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
125 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
323 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
116 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 ...
2
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0answers
234 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 ?.
7
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3answers
500 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
54 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
152 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 ...
0
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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 ...
0
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1answer
56 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
374 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
4
votes
2answers
674 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 ...
1
vote
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 ...
0
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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?
0
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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 ...
1
vote
1answer
185 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 ...
1
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2answers
2k 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
votes
2answers
585 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 ...
1
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1answer
596 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 ...
1
vote
1answer
344 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] ...
0
votes
1answer
140 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
votes
1answer
854 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
123 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 ...
0
votes
4answers
520 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 ...
0
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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, ...
1
vote
1answer
168 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
votes
1answer
412 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
654 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 ...