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

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4
votes
1answer
685 views

Is there a way to run a python script on opening a QGIS project?

I have a .csv file containing financial data which is generated on a regular basis outside QGIS. Then I want to create a PyQGIS script that will add the .csv file as a layer in my project. (The idea ...
1
vote
2answers
86 views

How can i change the geometry of an existing layer?

I work with Qgis, v. 2.0.1. I have a point layer in which I have structures that could be represented as lines or polygons, but at the moment they are represented as a group of points. I know I can ...
1
vote
1answer
86 views

naturalearth sqlite db not loading into qgis 2.2 [duplicate]

I downloaded the naturalearthdatabase in sqlite-format (http://www.naturalearthdata.com/downloads/, the downloadlink goes to http://kelso.it/x/nesqlite), but qgis 2.2 (running under win 7 64bit) does ...
1
vote
2answers
54 views

How can I determine which polygons contain other polygons?

I am using only free, open source tools. I have two shape files: a shape file of voting precincts and a shape file of census tracts. I want to know: which voting precincts fit inside which census ...
1
vote
1answer
51 views

How do I get the attributes of a particular polygon in qgis

I downloaded a shapefile that has demographic data for census tracts for a city -- each represented by a polygon in the vector layer. I can click the attribute table icon to see the whole sheet of ...
2
votes
1answer
44 views

Is there a way to get create label classes similar to symbology classes?

Is there any way to get the same classes of label size as by the symbols? For example: i devided towns according to their population to 5 classes (as graduate symbolology), and want to label each ...
2
votes
0answers
64 views

QGIS Labels: letter or word spacing ignored after export

My line label have letter spacing of 3px (Layer Properties -> Labels -> Text -> Spacing -> Letter). In print composer everything is drawn like I want it but after export to svg, pdf, or image the ...
4
votes
1answer
382 views

How does QGIS calculate heatmap values?

I made a heatmap from points (with values) in QGIS, and now try to understand what the values in color scale are. Radius 300 map units (meters) Pixel size 10 map units (meters) Point values are ...
2
votes
3answers
2k views

QGIS Desktop 2.2.0 - program does not start

I just installed QGIS 2.2 (I download QGIS Standalone InstalleVersion 2.2 (32 bit)).Installation was successful without any errors. Then I try lunch QGIS Desktop 2.2.0 but the program does not start. ...
1
vote
1answer
96 views

Purpose of “myPlugin_dialog.py” file created by QGIS Plugin Builder

I usually use QGIS Plugin Builder to create working templates for QGIS plugins. While a generic Python plugin needs the files below; __init__.py metadata.txt resources.py (translated from ...
0
votes
1answer
158 views

Threejs “Failed to generate a dem file using gdalwarp. gdalwarp is not installed.”

I am trying to test out the new threejs plugin for QGis and have come across this error. Failed to generate a dem file using gdalwarp. gdalwarp is not installed. I have installed the latest ...
0
votes
1answer
102 views

Setting default browser for QGIS actions

I am trying to open a pdf using QGIS action tool with Adobe Reader. Currently, the action defaults to Internet Explorer which doesn't succeed in opening my document. I'm currently able to open AutoCAD ...
2
votes
1answer
438 views

How to select only polygons that overlap with another layer?

I have two shapefile layers created from different thresholds from a predictive model (Pink=80; Yellow=95). Is there a way to create a new layer of only those pink polygons that contain yellow ...
3
votes
1answer
398 views

Got Null values when updating attributes with PyQgis

I'm trying to create and update a field and ,for now, just change it's value to 2. Here is my code: layer = qgis.utils.iface.activeLayer() index = layer.fieldNameIndex("P") # if index == -1: # ...
0
votes
2answers
55 views

Is there any way to use open source tools to make sure that lines on a map dont overlap?

I am a generalist developer getting the hang of basic gis. I made this geojson map by clipping and converting different shapefiles. The problem is that the precincts of New Orleans extend into the ...
3
votes
0answers
242 views

Does QGIS support .sld style files for raster layers?

I'm currently looking at the documentation for geoserver, and I'm trying to load a raster and .sld file in QGIS to see if I can edit .sld files for raster layers. The .sld and raster are located here: ...
0
votes
1answer
451 views

qgis-web-client stuck on Loading Map

I'm trying to publish a map created in qgis desktop via qgis-web-client. The left hand bar loads with the layers I would expect visible but I never actually see any mapping data just a grey screen ...
5
votes
1answer
525 views

Calculating Topographic Exposure with Raster Calculator

I need you help trying to calculate Topographic Exposure (TOPEX) on a DEM in ArcGIS. I am trying to figure out wind exposure on a DEM with 25m cells. There is a great blog post where someone explains ...
0
votes
0answers
21 views

Set region around multiple polygons

I have combined multiple objects per row in my layer. Is there a way to build another layer that surrounds the combined objects, per row?See example. For Q-GIS, thx.
1
vote
0answers
158 views

Defining the boundary of a catchment area

I digitized contour lines from topographic maps and created a DEM. With the DEM, I estimated the boundary of a catchment area. Estimated positional accuracy of topographic maps is RMSE = 65 m, with a ...
0
votes
2answers
55 views

Erase within a feature class - Planar enforcement

I´m using ArcGIS v10 ArcInfo. I´m working with a feature class that has 5 features which are waterdepths (1 to 5m). These features are overlapping each other. What I need, is that they are not ...
0
votes
1answer
88 views

Match bicycle routes to street lines

I have a KML layer of bicycle routes and a street line layer. Using either ArcGIS or QGIS, how can I select the streets that correspond to the bicycle routes?
0
votes
1answer
134 views

How do I control rendering order of items in composer?

Alternative formulation of the question is: Is there any other way apart from the order of adding items to the canvas of setting the rendering order> The problem is that I want to change the map ...
3
votes
1answer
1k views

Georeferencing an image with GDAL, based on QGIS Georeferencer Plugin

I would like to georeference an image with GDAL. The image already has a spatial reference set (EPSG:31276). For the georeferencing, I have a list of 4 ground control points (also in EPSG:31276). ...
2
votes
0answers
31 views

changing central meridian in QGIS causes problems [duplicate]

I want to change the central meridian of my world map (WGS84) in QGIS from 0 to -80. The problem is that this distorts the map every time I try it. This is what I do: go to Settings/Custom CRS ...
0
votes
0answers
79 views

How to activate edit tools

I have opened a project I worked on earlier on another machine, but the edit tools are not active, so i cant turn on editing to change a layer. What is the reason for them to be gray, and how can i ...
1
vote
1answer
103 views

What is the difference between QGIS for Windows and QGIS for Android?

What is the difference between QGIS for Windows and QGIS for Android? Is the functionality the same?
1
vote
1answer
121 views

How to add pages in print composer

Is it possible to add more than one page to one QGIS print composer Project? For example one sheet for the map and another sheet for the legend ans some other informations. Thanks in advance, Patrick
2
votes
1answer
646 views

How can I filling ring in QGIS 2.2?

I created a polygon which covers a park. But I want to distinguish some small buildings located inside the park. Consequently, I want to distinguish them and use them as independent patches inside the ...
0
votes
1answer
330 views

QT Designer form - Combobox stores value but doesn't display it

I have a custom form created with QT Designer on which I have several comboboxes among other stuff. All the fields have the correct names corresponding to the database. One of these comboboxes has a ...
0
votes
1answer
160 views

Duplicate values in combobox in QT Designer form

I have a custom form created with QT Designer on which I have several comboboxes among other stuff. All the fields have the correct names corresponding to the database. But something weird and ...
4
votes
2answers
252 views

Migrate to QGIS?

Is it sensible for me to migrate to QGIS? I've been using OCAD, a very old vector based map software to maintain a local "back country" map. With OCAD6 I initially import base data, e.g. contours, ...
2
votes
1answer
508 views

Failed load delimited layer in QGIS python console

I'm trying to follow the map rendering section from the pyqgis cookbook. I am able render shape file using qgs vector layer, however getting error prompt while loading delimited text file through qgs ...
6
votes
1answer
287 views

GDAL equivalent of ArcGIS Mosaic

The word 'mosaic' is often used for quite different things within the worlds of ArcGIS and GDAL. With GDAL and it's downstream applications like Qgis it is common to see mosaic used in the context ...
0
votes
1answer
33 views

When styling with data defined properties or Labeling, Is there a way to replace an ID representing field with the actual values depicted by the ID?

I am currently using data defined properties and labeling to present pipes based on diameter. I now have a dictionary table that has id's for every combination of diameter and material and I'm using ...
0
votes
1answer
155 views

Labeling expression to label one value in a attribute table column

I am using QGIS 2.0 on Windows. I have a shapefile for a point layer that has the the following attribute table: I am trying to label using the Status column and only want the value that equals ...
1
vote
1answer
148 views

using postgis function in pyqgis

I'd use Postgis function in Pyqgis script. This code: qsql="(select gid, id, St_Buffer(the_geom,200) as geom from archi)" uri = QgsDataSourceURI() uri.setConnection("ip", "port", "x", "x", "x") ...
1
vote
0answers
179 views

PyQGIS Dialog Plugin not resetting

I have written a PostGIS search plugin that works pretty well, except two things that I just cannot figure out a solution 1) When the dialog closes and then is reopened the previous query is still in ...
0
votes
1answer
258 views

Calculating distance between coordinates [duplicate]

I would like to calculate the distances between a list of coordinates (classic GPS coord.). From coordinate A to B from B to C from C to D and so on, and so forth. Is there any program, or website, ...
0
votes
0answers
28 views

The graduated symbology doesn 't take into account the attribute I need in QGIS

I m working on a project on QGIS I have a point shapefile vector that represents my store In the attribute table, i have bunch of data such as size, unit per transaction and most importantly store ...
1
vote
1answer
523 views

Editing WFS with max feature limit in QGis

I'm serving a large layer (500 thousand polygons) using Geoserver WFS and what to be able to edit it using QGis. I've set a feature limit on the layer so I wont overload GeoServer with the request. I ...
2
votes
4answers
772 views

Combining different geometry types into same feature class?

I've searched the question in this blog. Maybe I don't use the right words but anyway my problem is not present in any post so I'll try to explain my question by opening a new one. I have a polygon ...
1
vote
0answers
230 views

Zoom to Selected Feature for point layers in QGIS 2.0

I find the QuickFinder plugin for QGIS 2.0 very useful to quickly search, find, and select data. However, I'm under the impression that checking the "scale" option doesn't seem to do anything. I ...
1
vote
1answer
499 views

visualize bounding box to a polygon

I try to make plugin in QGIS that compare 2 bounding box data, ex: (-32.61442167739459, -32.017601026186576, 13.015663782506067, 13.428145228091406) and (-38.6102467739459, -38.017601026186576, ...
2
votes
1answer
571 views

Code works on python console in QGIS but same doesn't work in stand alone script

I'm trying map rendering with stand alone script, so I have small script which works fine in python console provided QGIS, however when I run same code in stand-alone script it executes without error, ...
1
vote
0answers
28 views

Able to circumvent QgsCredentials script called from Pre-execution

I've got a stored project that, when opened is connecting to my PostgreSQL DB, and is loading several layers. All good. I'm using a script that is called from Pre-execution (Processing/Options and ...
1
vote
0answers
32 views

What can I do in qgis to manage a WMS frequently unreachable?

In my project I have a layer linked to an external WMS server (provided by a local institution). The problem is that it is somewhat unreliable: it is down rather often. Is there something I can do to ...
2
votes
0answers
265 views

How do I catch PostGIS/PostgreSQL RAISE messages in QGIS?

I have a trigger set up in PostGIS/PostgreSQL which will show a RAISE WARNING when an inserted or updated polygon is within a certain distance of some predefined planning constraints. I want this ...
1
vote
4answers
586 views

How to change a CSV layer attribute value from text to number - once again?

i have read most of the related postings and answers allready ... (e.g. http://anitagraser.com/2011/03/07/how-to-specify-data-types-of-csv-columns-for-use-in-qgis/ and How to change a CSV layer ...
1
vote
3answers
127 views

How to add data to an attribute table?

I have a shape file (points) and would like to add points using the attribute table and not the Add Feature tool at the main screen. I went over the Qs here, but didn't find a similar problem to ...