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

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92 views

Create and immediately update field using Field Calculator

You can create fields and once created, populate them with data using the Field Calculator. But can you do both at the same time using an expression? Or must you do it in 2 steps?
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1answer
72 views

How to deal with empty corners in raster when calculating fragmentation index

I have clipped buffer area around coordinate from one big raster (forest cover). Such created raster was loaded in R where PatchStat function (library SDMTools) gives fragmentation index. After ...
3
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2answers
329 views

How to generate Non-smooth/crude Contour Lines in QGIS?

I have an SRTM DEM and I want contour lines generated for specific elevations. This can easily be done using r.contour.level/step etc. but the contours generated are smooth and cover the cells only ...
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1answer
1k views

How to create a dock widget correctly in QGIS plugin?

I am building a QGIS plugin and would like to use a dock widget. I have used QT creator to design the UI, with the object type being a QDockWidget. When the plugin is enabled in QGIS the dockwidget ...
2
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1answer
323 views

Mac OS X 10.6.8 QGIS not using user-installed Python 2.7

My QGIS does not recognize the recently installed python 2.7 on my mac osx 10.6.8. it still uses the python version 2.6 that is automatically installed by apple. Opening qgis I always receive an ...
2
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3answers
2k views

Convert Shapefiles to GeoJSON?

I'm trying to convert Shapefiles from the State of Texas Senate Districts website into a GeoJSON file for use with Google Maps API. I'm using QGIS to facilitate but I can't get the ...
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0answers
97 views

Using iface.showAttributeTable() on QgsVectorLayer retrieved by getObject()

I'm unsure if i'm properly using the processing.getObject() function. I'm creating a python processing script for QGIS 2.0 and 2.2, but can't seem to get an attribute table to open programmatically. ...
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2answers
48 views

Creating Many Uneven Buffers

Qgis 2.2, Windows 7 I am looking to create buffers around city lights (the raster). Currently, I have simple polygon buffers around the point layer (oecdminusa), but this is not accurately capturing ...
2
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1answer
138 views

polygons and lines not drawn correctly (qgis+postgis)

i am really new to this so i could use some help.. i load osm file into postgresql and then i connect to the database with qgis t to plot it and i see this it happens to whatever file i import to ...
2
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3answers
1k views

Is it possible to export cross sections from QGIS to HEC-RAS

Is it possible to create cross sections along a river in QGIS and then export the data to HEC-RAS? Thanks
2
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1answer
464 views

QGIS/PostGIS layer styles

I've made a plugin asking for login credentials to a DB. Once logged in, the plugin is loading some layers from the DB. In the DB there are both admin and "normal" users. I've saved two styles to the ...
0
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1answer
344 views

Dissolve large dataset in ArcGIS and QGIS

I have more than 80k point data. I have created few buffer from 1 to 5 km of them. Now I want to get the covered area by 1 km to 5 km buffered range. For this I have tried to dissolve those individual ...
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1answer
145 views

How can I change the coordinate system of gpx-points?

I'm working with qgis, v. 2.0.1. I have some points from a gps device (Garmin) and they already are in the .gpx format. Now I have two problems: First, I can't open the gps-Points with the "gpx-tools" ...
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0answers
245 views

Issue blocking QGIS feature form dialog with Python

I'm not sure where I'm going wrong with this python logic for a custom form in QGIS 2.0.1. There are a few things required by the validation function: that index of combo boxes aren't 0 (first index ...
2
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0answers
147 views

How to eliminate gaps and overlaps in a layer of SpatiaLite table?

I'm try to snap all polygons in a table to remove gaps and overlaps. I can remove gaps but get new overlaps. I have no idea what doing wrong... sorry, I'm new in SpatiaLite. I tried the following: ...
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1answer
80 views

Qgis 2.2 georeferencer always shows 0.00 dX, dY and residual. My fault or bug?

I'm georeferencing a map (jpeg) in UTM coordinates and everything works fine exept, i the referencer window doesn't give me any residuals or dX/dY values. When I change the coordinates of a point on ...
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1answer
188 views

Processing Script: now gives error in QGIS 2.2

I recently updated to QGIS version 2.2, and am now getting an error when running Processing scripts that worked previously (in version 2.0.1). Uncaught error while executing algorithm Traceback (most ...
3
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0answers
86 views

Using Field Calculator to Convert Data Type In Field

I am trying to convert a field that is listed as "String" because it was imported into QGIS as a CSV (rural poverty population percentages by county in NC). I need to convert the percentages field ...
4
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2answers
1k views

QGIS relations widget in custom form

I've just begun exploring QGIS relations option, now in version QGIS 2.2, details here: http://blog.vitu.ch/10112013-1201/qgis-relations This is a great implementation of something I've been ...
2
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1answer
949 views

Problem opening shape file in qgis

I am having a problem opening a shape file using QGIS using 'add vector later'. This is the error message i am getting: /Users/Conrad/AmerindianLands 2/Amerindian_Land_Karasabai.shp is not a valid or ...
2
votes
1answer
989 views

Adding graticules to the edge of the map only in QGIS

I would like to add graticules to a map, once it is in the 'print composer', on the border of the map, and not on the frame (my map insists on being smaller than the frame). I have managed to add a ...
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0answers
60 views

QGIS - Atlas. Outputs missing

This really teases me. Somehow the Atlas-function in Print Composer are missing some of my polygons from my layer, when doing a print. I´ve looked at them once again,- they are there, and the geometry ...
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1answer
449 views

Adding attribute list to combobox in a python plugin

I am developing a simple plugin at the moment which contains 3 combo boxes: comboBox_1 comboBox_2 comboBox_3 Combobox 1 & 2 lists the vector layers available, however I would like the 3rd ...
4
votes
3answers
170 views

How to shrink polygon on two sides?

I have a polygon which I know is a rectangle, although it may be at any orientation: I want to shrink this polygon by a third of the width from two sides, so that I just get the strip in the middle ...
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0answers
93 views

Raster format similar to ECW

I need an alternative to the ECW format that we currently have for a new series of Ordnance Survey maps. The ECW format looks clearer and less pixelated than the new maps in Tif format (in QGIS). ...
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1answer
76 views

Importing data into a project with a custom CRS incorrectly projected

I created a custom CRS for a project I am working on. I then started a new project, set to my custom CRS and turn on "on the fly" transformation. I import Rail data that I know is in my custom CRS, ...
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1answer
113 views

Georeferencing an aerial image based on satellite imagery

As part of a bigger project I need to georeference an aerial image based on a landsat image downloaded form usgs. I use qgis. can I somehow place the layers on top of each other and mark certain ...
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0answers
85 views

QGIS crash when selecting a Select Single Feature in attribute table

I'm loading several layers, styles and setting up some layer relations in a plugin that I execute. Once this is done I manually 'Select Singe Feature' on my map, switch to the "non-table view" in the ...
0
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1answer
428 views

Link Google Earth with QGis

I was wondering if it was possible to link Google Earth files (KML, KMZ) to a QGIS project. The main idea would be that if you'd add a point with coordinates in Google Earth, this point would be added ...
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1answer
1k views

What is the format expected by QGis for Latitude/Longitude in DMS?

I have been struggling with a csv file I need to import into QGis 2.2.0 (on Windows 7). The coordinates are in this format: LATITUDE LONGITUDE 424605 861204 395222 861206 303051 861219 ...
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0answers
96 views

Cannot Save Edits to File Geodatabase Replica in QGIS 2.2

When trying to edit a File Geodatabase Replica in QGIS 2.2, everything works as expected until the user saves their edits. When pressing save, all edits revert back to their original state with no ...
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2answers
328 views

How to select objects by N:M join?

I have a layer with some geometries and a data layer that defines an M:N relation. Is there any way I could select (on the map) objects that are in relation with specific id? Basically I would like to ...
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0answers
135 views

producing a bathymetric map in qgis with limited depths measurements

i am new to your community and hope you to find tips on how to work with the following project. i want to produce a bathemetric map (depths profile) of a water area. I do have aerial images and 3 ...
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1answer
256 views

Is it possible to link a QGis project with an excel file?

I have an Excel file with coordinates and I have used this file to plot the coordinates in QGis. I was wondering if it was possible to permanently link the excel file to the QGis project, so that when ...
2
votes
1answer
218 views

How to create polygons from a polyline graticule?

I'd like to make a polygon shapefile out of a polyline shapefile showing a graticule. However, using the "Line to Polygon" tool results in a peculiar...something: Other standard tools like ...
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1answer
79 views

Interactive Gis application [closed]

I'm developping an interactive web(HTM5) gis application wich the user draw an element(circle for example)and extract data from base map(Open Street Map).The features would be: 1º Base Map like OSM. ...
2
votes
1answer
504 views

How to adjust QGIS attribute table view column width using Python?

I'm programmatically opening the Attribute table via Python through a plugin. All of the columns have a default width, but some of the data that I'm using do not fit. It's not enough to be able to ...
2
votes
1answer
279 views

Wrong lon and lat

I am using QGIS 2.2.0! I have shape file with wrong coordinates, it's had replaced x coordinate with y coordinate. For example my point feature have coordinates: 4830698,7496859 and right coordinates ...
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1answer
233 views

PyQGIS loading layer style with PostGIS

I'm loading layer styles from .qml files in a Python plugin. I'm about to switch to loading them from a non-local postgreSQL db. I've been looking at the (from QgsVectorLayer (v2.2)) ...
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1answer
95 views

Is it possible to do a query to multiple tables?

I have a point a line and a polygon layer. They have the same attribute table. Can I do one query that refers to all the attribute tables? So I wouldn't have to do every query three times. Thanks. ...
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0answers
79 views

Calculating Percent Overlap Between Distribution Maps

Hello there, I am currently trying to calculate the percent overlap (basically the total amount of overlap where these two species come into contact) between Lithobates catesbeiana (first image) ...
2
votes
1answer
75 views

Displaying QGIS layer after loading with Python

I'm successfully loading several layers with Python, but can only get to see them in the map window if I manually zoom to extent afterwards. Once the last layer is loaded I call zoom to extent in the ...
1
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1answer
194 views

Python.dll could not be loaded with PyScripter

I'm trying to configure PyScripter with QGIS. I've installed it using OSGeo4W and I'm following instructions to setup a pyscripter.bat file by copying content of qgis.bat file. I have the following ...
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0answers
90 views

Ubuntu Touch and QGIS?

I'm planning buying a tablet for running Ubuntu. There are little info on experience with Ubuntu Touch and QGIS and does it work? What I want is to run it on the tablet, drawing polygons etc on ...
1
vote
1answer
141 views

QGIS Custom Form: “Other” category in combo box replaced by line edit [closed]

I am trying to create a custom form for QGIS 2.0 with comboboxes containing an "other" category. I wonder how to provide a line edit to enter info replacing the "other" choice if chosen. Not sure if I ...
2
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1answer
72 views

Upright/Horizontal lables when labeling polygons at perimeter?

I have several polygons (circles) I want to label with their ID number. The label should be outside the circles so I use the positioning options "Use perimeter" and the tickbox "Next to the line (or ...
3
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0answers
364 views

Why does the QgsVectorFileWriter have probelms creating vector files? [closed]

I am using QGis 2.0.1 and have tried to create a new GIS feature file (SQLite, Spatialite, and Shapefile) of a subset of the data. I am then saving a copy of the style of this layer and applying it to ...
1
vote
1answer
86 views

Why do the raster band values have different values than the raster statistics?

I am working on a raster file (1 Band). According to the raster metadata, my minimum value is 0 and maximum is 7458. This seems to be confirmed by the Style options that return some category values ...
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1answer
73 views

Overlay polygon on raster and save as new raster with same resolution

New to GIS and trying to learn. I'm trying to take a blue marble raster, overlay a countries .shp file, and save an image with the original blue marble image and the country outlines "burned into" the ...
5
votes
1answer
210 views

How to open QGIS attribute table in form view using Python?

I've got a plugin where I load some layers. After the last layer loaded, I show the attribute table. However, I would like to select the form view and not the table view (see image). How can I do ...