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

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4
votes
1answer
2k views

Split vector layer by field name

I have a vector layer of 108374 lines I want to split the vector layer into field names of the layer, which is 17. Now, I want to create a new vector layer containing one of the field names e.g. ...
4
votes
1answer
229 views

draw lines with an angle inside a rectangle in python

I am trying to make a plugin for Qgis with python. I have the four corner coordinates for a rectangle. I want to give the user the inputs, line space and angle (0 -180 degrees). With these inputs, I ...
3
votes
2answers
1k views

How to set up QGIS print composer options from the python console?

If I have a print composer called "ABC", I would like to "tell" its composer that I would like to update "Map 0" to simulate the "set to map canvas extent" button activation update certain text ...
1
vote
0answers
209 views

Couldn't load SIP module - python disabled

Recently my QGIS started refusing to load SIP module, from day to day without any significant changes in the system (I'm on Windows7 x64). Message thrown at startup: Nie można wczytać modułu SIP. ...
0
votes
0answers
82 views

How to populate polygon extents to an attribute table in QGIS

Is there a way to calculate the XMIN, YMIN, XMAX and YMAX of a polygon and write it to a field in an attribute table? The Geometry functions available in the Field Calculator are for points. ...
1
vote
1answer
380 views

How to center the labels in QGis?

I have a shapefile containing some US sections from the Public Land Survey System. I would like to display the labels in the middle of the sections. I found the "Placement" option in the "Label" ...
2
votes
1answer
202 views

selectedFeatureCount vs featureCount?

I do from qgis.core import * layer = QgsVectorLayer(r"D:\file.shp", "boundingBoxes", "ogr") layer.featureCount() outcome is 428 layer.select(layer.pendingAllAttributesList()) ...
1
vote
2answers
56 views

In Quantum GIS, how do I specify the units for a shapefile?

I'm trying to create a shapefile of fields, drawing polygons around each field, and having the acreage calculated in the attribute table. I believe I have the projections correct. It's not coming up ...
3
votes
1answer
162 views

CRS Austrian Lambert/WGS84

I am totally new to Qgis (or GIS in total): My problem is to get two layers in same CRS to do an intersection and further analysis described in the blog of underdark (Groupstat tutorial). My is the ...
7
votes
1answer
303 views

How to access and/or manipulate table data in QGIS composer label?

When setting up a map to print using the QGIS Composer, how can I insert a label linked to a specific table record? I have been using the latest development build (1.9.0) which has the new Expression ...
1
vote
2answers
2k views

Can QGIS (1.8.0 Mac) rotate the entire view of a project?

Can QGIS (1.8.0 Mac) rotate the entire view of a project? that is, have north pointing in a direction other than up on the screen and on output? of course, while still allowing adding new layers etc.
1
vote
1answer
223 views

How to apply new WFS-Filter features like intersect

I was pleasantly surprised to find very much enlarged filter support in QGIS-Dev (1.9.0_Master). One application would be a WFS-Filter which combines $geometry and Intersect in order to load only the ...
3
votes
2answers
2k views

How to read the attribute values using PyQGIS?

What is the way to get the information contained in the attribute table, say in column 2, row 2 using pyQgis?
4
votes
1answer
603 views

What functionality exists to calculate Cut and Fill for excavation?

Does qgis have the ability to compare and quantify existing versus proposed elevations?
3
votes
3answers
120 views

How to match air photo to existing vector layers on Mac OS?

I'm trying to add an air photo to a project and match it to existing data. CanVec data is mostly based on the old CIA dataset of the 60's and is hopelessly out of date, but the roads are up to date - ...
4
votes
1answer
346 views

Can county level info be brought into a map?

I have a csv file of Clovis projectile points that were recorded only with the county in which they were found, no coordinates at all, no shapefiles. Is there a way to bring these into a state map ...
6
votes
2answers
1k views

QGIS, Postgis: Is it possible to create a new postgis layer?

Situation: I have a postgis vector lay that has lots of line segments (the features). I want to create a set of new layers each of which contains a subset of the features of the original layer and ...
2
votes
1answer
64 views

QGIS: Making changes to vector layers stored in PostGIS

I have a vector layer stored in PostGIS. I split several lines in the layer and simplified others by removing vertices. When I tried to save the changes to the layer I got postgres more postgres ...
15
votes
2answers
2k views

How to create contiguous area cartograms in QGIS or R?

Here is what I want to achieve (on the right): I am looking for a tool or a method to transform a shapefile (with QGIS or R) into this form. And please be aware: It's not just clipping a hexagonal ...
1
vote
0answers
519 views

How to use raw_input() in QGIS python console?

I'm hoping to use raw_input() inside a loop to prompt the user when s/he wants to continue running the script. However, I'm getting an error: Traceback (most recent call last): File ...
2
votes
2answers
576 views

Create polygon of buildings from Quickbird images in QGIS

I have Quickbird/Ikonos/GeoEye image and want to extract all the buildings from the image as an independent layer in QGIS. How can i achieve that?
1
vote
2answers
780 views

Having problems creating VRT in QGIS from png files

This is similar to a question asked by someone else, re OS tiles, however, there is a difference! I am a bit of a amateur in GIS and python, but if I take it slow I can usually just about work it out! ...
5
votes
2answers
804 views

Field Calculator decimal places - how can I limit them?

I've added a new column to an attribute table and performed an operation with the field calculator to populate the new column. The result is a column with a percentage. My problem isn't major but I ...
1
vote
2answers
1k views

styles for QGIS

Could someone point me to a source of line and point styles for QGIS (*.qml) - railways and transmission lines are the first two I've run up against, but I know there will be more.
1
vote
1answer
304 views

Rpy2 Unable to Load in Fresh QGIS Install

after installing qgis the a message given below is shown Unable to load the plugin: Unable to load required package rpy2. Please ensure that both R, and the corresponding version of Rpy2 are ...
2
votes
0answers
243 views

QGIS not rendering WMS layers

I'm a bit of newb' at GIS so be gentle with me. In Qgis I've set up a wms for the British Geological Survey: http://maps.bgs.ac.uk/ArcGIS/services/BGS_Detailed_Geology/MapServer/WMSServer? Now ...
4
votes
1answer
375 views

Personal shell launcher for PyQGIS

I have changed a shell launcher found at http://inasafe.linfiniti.com/html/id/developer-docs/platform_windows.html as to fit my wish: setting the system environment variables to be able to use PyQGIS ...
2
votes
0answers
329 views

WMS and Quantum GIS/ArcGIS

I periodically use a nice basemap served by the Utah state government in QGIS. Recently they upgraded their server from ArcGIS Server 9.3 to ArcGIS Server 10.1. Ever since then, I can't seem to get ...
2
votes
1answer
190 views

Can not import qgis.core in python

I installed OSGeo4W. I have no other Python version on my computer. I can import osgeo. But when I try to import qgis.core I am getting the error: >>> import qgis.core Traceback (most ...
6
votes
1answer
847 views

ISIS to GDAL to QGIS: Georeferencing Mars Images

I'm trying to use QGIS to view some images from the Mars Reconnaissance Orbiter Context Camera. I use ISIS3 to download the images and convert them to mapped .cub files, following the instructions ...
2
votes
0answers
75 views

How to delete a point with known coordinates in python?

I was wondering if there is a piece of code that does the opposite that setGeometry does and removes a point if there is one at x and y coordinates?
4
votes
3answers
2k views

Can OpenLayers layers in QGIS have transparency?

I often would like to set the basemap back by lowering the transparency. I would love to have this option in QGIS for OpenLayers layers, such as the stamen layers, google, etc. Is this possible? I ...
0
votes
0answers
229 views

How do I stop polygons from a .kml layer disappearing as I zoom in on the layer?

I am relatively new to GIS stuff and have a query about .kml files in QGIS. I have downloaded the .kml filefrom ...
1
vote
1answer
154 views

Modify 'Codepoint with Polygons' to add new fields

Sorry if this is a simple question - I'm just beginning in QGIS. I'm using OS Codepoint With Polygons data set which provides shape files of each Postcode area within the UK. Within each postcode ...
4
votes
1answer
530 views

How to measure the distance of multiple points to a line

I have two shapfile in QGIS to which I am trying to find the distances between. I have a shoreline which is a vector line and then I have hundreds of data points in the ocean. What I am trying to find ...
3
votes
0answers
519 views

Transform RGB-Map to CMYK (qgis, opensource tools)

I want to print a map I made with qgis. For the print I need CMYK-colors but the print-composers pdf-output is RGB. How can I convert the RGB-map/-pdf to CMYK?
1
vote
1answer
168 views

How to run “create mask” from the console?

There's a plugin called "create mask" for qGIS and trying out some simple scripting from the Python console. I would like to call it after I select the vector features I want, then do more related ...
6
votes
1answer
87 views

Is there a way to select only a certain polygon for editing?

I have a spatialite data base with 4300 polygons contained within. I wish to be able to edit the polygons but once i have highlighted the Polygon from the attributes table i find it hard to edit the ...
1
vote
0answers
64 views

Avoid rounding of coordinates in pyQgis

If I get the coordinates of a polygon in qgis by x = geom.asPolygon() It rounds off the coordinate from i.e. -27,200,334.86 to -2.72003e+07 How can I avoid that?
0
votes
2answers
269 views

loading CanVec directory full of .shp files

I'm totally new to QGIS, and trying to view a Canadian Topo map as published on an iMac - I don't want to change it. ...
1
vote
1answer
94 views

How do you Select an existing vector Layer and Edit it, using python?

I'm developing a small plugin that needs to be able to select a vector layer programatically based on what layer the user has selected. However I'm not sure how to do so. I believe I found the two ...
3
votes
3answers
174 views

QGIS Python Intro Text

After reading replies regarding starting a mapping business, I think I'd better read a Python book. Any intro-level Python books to recommend? Mila
5
votes
2answers
3k views

Total of attribute field of point layer per polygon layer

I have a polygon shapefile of many lakes, I also have a point shapefile of locations on those lakes where fish were caught. The point shapefile contains the attributes: Fisherman_iD, Fish_Caught, ...
2
votes
1answer
177 views

Setting coordinate systems in QGIS: “transform error caught”

I'm learning how to use QGIS (v 1.8.0 "Lisboa") on Mac OS 10.6.8. My goal is to create a simple county map of Illinois using the base data shapefiles available from the Illinois Natural Resources ...
1
vote
1answer
116 views

Seeing only default list of KML attributes in QGIS attribute table?

I converted a shapefile to kml using ogr2ogr. Glancing at the output, it looks correct -- it has a <Schema ...> and each <ExtendedData> references the schema (I uploaded a snippet here). ...
9
votes
3answers
983 views

How to Display Overlapping Lines?

I have multiple line layers that represent bus routes and many of the routes overlap (i.e. near terminals, transfer locations, etc.) Is there a function in Qgis which will display both features ...
0
votes
1answer
316 views

QGIS not Printing to PDF [closed]

Simple QGIS 1.8.0 not printing to PDF. Suddenly stopped. Is this an error or something. the resultant PDFs are blank pages. When i file print and use a pdf printer it creates blank docs. when i ...
3
votes
1answer
213 views

How to select features by matching attributes of two SHPs?

I have one line shape file with lot of road sections and a point shapefile, some of these points are outside my area of interest. The files have one attribute in common and I would like to do ...
6
votes
1answer
2k views

QGIS Zoom from python console

What are the commands to apply all types of zoom (full, on selected layer, etc.) in python console? I'm searching both on pyqgis cookbook and API documentantion, but I'm not finding anything ...
1
vote
1answer
348 views

Rasterize vector with gdal

"I would like to calculate the Euclidian distance from a residence to a public service of interest e.g. the distance from a residence to a green space (as the crow flies) in QGIS. After browsing the ...