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

learn more… | top users | synonyms (1)

0
votes
1answer
35 views

Is possible to create a new column of QGIS?

I want to create a new column according to the column A & column B. Column A 1 2 3 Column B A B C New Column 1:A 2:B 3:C How can I do that in QGIS? Thanks.
0
votes
2answers
150 views

Calculate length of line across zones with at least m accuracy

I have created lines between multiple points that are across MGA 54 and 55S (EPSG 28355). I am trying to calculate the distance between points but different methods give different answers (~1km ...
0
votes
1answer
87 views

Geographic Transformation Qgis

How to Define projection and enter the Geographic Transformation parameters from SGL-GEO to WGS84 in QGIS? Thanks
1
vote
0answers
190 views

Load MrSID file in QGIS 2.2 on Ubuntu 13.10

Is there a way to do this? I have tried a number of the write ups on this, and it appears that libgdal-mrsid-src no longer exists. Is there any other workaround? USDA NAIP imagery is sent as MrSID.
0
votes
1answer
195 views

QGIS linking census shapefiles with geocoded addresses

I'm trying to merge a census shapefile of New Orleans with a health outcomes dataset by address with QGIS. I have geocoded the addresses and added them as a layer in QGIS but don't know on which ...
-1
votes
2answers
566 views

Polygon shapefile to Raster with Mask and Extent

I have a polygon shapefile (Vesijärvi lake). The lake has many islands, bays and inlets. When I look at the attribute table, there are actually two adjacent features: Northern lake and southern lake. ...
3
votes
3answers
114 views

Field calculator problem

I have an issue withe the field calculator. It is impossible for me to multiplicate 2 columns (area * KZ). The result is always "0". I used the formula area * KZ....is this the right formula? LINK to ...
2
votes
1answer
767 views

Problem creating point shapefiles programmatically using python in QGIS 2.2

I am trying to create a point shapefile in the memory buffer (for a temporary label) and then zoom to the extents on this buffer. The working (in version 2.1) test code for this is: def ...
1
vote
1answer
289 views

Adding MrSid to QGIS

I'm fairly new to QGIS and was hoping someone could help me load some MrSID photos into QGIS. I have read some posts and have installed the OSGEO4W Installer and selected the GDAL-MRSID Lib. I ...
5
votes
2answers
283 views

How to calculate the area between two line shapes?

I'm a newbie using QGIS (2.0). I'm trying to calculate the sidewalk area of a city. For that I have some shapes, extracted from Mricostation, with the topology (facades, fords, fences, etc.), but ...
2
votes
2answers
116 views

How to handle multiple space separator in Grass?

I try to load a Lidar point cloud in .xyz format to Grass (in QGIS 2.0.1). I tried to input the following options to the 'separator' field: tab, 'tab', '\t'. Just for the unlikely case that it ...
1
vote
1answer
147 views

How to perform a standard deviation stretch on a raster in QGIS

Is there a way to perform a (2) standard deviations stretch on a raster image in QGIS 2.2? I have found the raster styles menu, but the help says there is no help in my language (English) and whilst ...
1
vote
1answer
170 views

When I join a table to a shapefile and then export it the titles of the columns are transformed to data1, data2

I'm using QGIS 2.0.1 The table is in an excel format that i import through "add vector" and the shapefile is a polygone I join the attributes by right clicking the polygone-->properties-->join Then ...
1
vote
0answers
202 views

QGIS plug-in equivalent of ArcGIS's Spatial Analyst Tools -> Overlay/ Weighted Overlay

Specifically I have 12 .bil raster files that show monthly global mean minimum temperature. I file for each month. I want to combine these to create an ANNUAL global mean minimum temperature. In Arc I ...
0
votes
1answer
80 views

QGIS Legend horizontal not vertical

Hi is there an easy way to have the legend linked to the size of the box it is drawn in. So instead of running down the side of the page, it will be across the bottom in columns? Does that make ...
0
votes
2answers
293 views

Union in QGIS: missing polygon boundaries

I am trying to UNION two shapefiles in qgis. I use the geoprossesing tool UNION. Both sf are in the same coordinate system (same as in the project). In the resulting sf some polygon borders are ...
2
votes
3answers
571 views

Draw line between points from multiple datasets

I have 2 point datasets and want a tool or script to draw a line between all points in one dataset to all the points in the 2nd dataset. Is it possible? I have tried ESRI "Point Distance" and ...
0
votes
2answers
2k views

QGIS select features from attribute table using the “LIKE” operator

I created an expression with the help of the GUI in the QGIS attribute table of a vector (shapefile) layer of Native American ("Indian") reservations in the USA state of New Mexico. "NAME" LIKE ...
0
votes
0answers
27 views

Show the paths but not roadsides and driveways in the line layer

I want to display paths in the woods but the paths are all in One (line) layer that contains all roadsides, pavements, drivvays, but also paths, tractor road and other relevant roads in, and up to the ...
2
votes
1answer
400 views

Change contour line stroke weight based on elevation?

I have shapefiles of contour lines that I have imported in Qgis. At the moment the contour lines are all the same stroke weight. I'm a beginner to this program, but wanted to know if its possible to ...
3
votes
1answer
258 views

Exporting a QGIS layout with Addition on layers

I've been playing around with an approach in QGIS that uses Addition between the layers I'm mapping to build a tri-variate composite colour map - an example is here in the QGIS Flickr pool: ...
1
vote
1answer
158 views

Why can't QGIS open my KML file? [closed]

I have a kml file with multiple absolutely identical polygons but with different names. I need to load it to qgis and find points in these polygons. But I guess qgis thinks that multiple duplicated ...
1
vote
0answers
65 views

QGIS crashes when digitizing new fetaures

I can't currently digitize polygon features in QGIS 2.01 or 2.3. I can draw a set of points but as soon as I right click to finish the system crashes. It still works fine in 1.8. Windows 7 64
1
vote
1answer
355 views

QGIS Quickly switching overlapping raster images

I'm new to QGIS, and haven't used arcGIS in about 5 years, however I've just seen someone using arcGIS and was able to quickly switch between overlapping rasters when checking registration. The top ...
0
votes
2answers
188 views

Interpolation using GRASS plugin in QGIS

I have been using the IDW interpolation tool through GRASS plugin in QGIS and the interpolation output I am getting is for the entire mapset region. My question is: Is there a possibiltity that we ...
0
votes
1answer
283 views

Merging Raster: ImportError: No module named _gdal_array

When I try to merge rasters I got following error message: _gdal_array = swig_import_helper() File "C:\PROGRA~1\QGISDU~1\apps\Python27\lib\site-packages\osgeo\gdal_array.py", line 18, in ...
8
votes
5answers
381 views

Print out the properties of the attribute table in qgis?

I have to merge a lot of shapefiles into one great shapefile. So I want to compare the properties of the attribute tables to see if there are differences between the tableproperties of each shape ...
0
votes
1answer
212 views

Using GRASS plugin tools from OSGEO4W command line

I am trying to do the interpolation of GRASS vector shapefiles using GRASS plugin tools. My objective is to run interpolation tool in GRASS plugin from OSGEO4W command line, which will help me ...
1
vote
1answer
448 views

Floating point calculations in QGIS

How do I manage floating point calculations in QGIS? I have carried out 3 consecutive calculations on landsat bands. I end up with 32 bit floating point rasters on which I can't carry out a 4th ...
0
votes
0answers
177 views

How to create a new table with point geometry column using QGIS DB Manager?

I have been trying to use QGIS DB Manager to create an empty table (QGIS 2.0 on Win7). My hope is that I can make an empty point file and use it to add data to, via heads-up digitizing (like you ...
2
votes
1answer
206 views

Maximum scale dependent visibility changes from 1:0 to -2147483648:1

QGIS 2.0.1 Dufour. When i open the layer properties and the scale dependent visibility is unchecked and when i check it, the maximum (inclusive) shows 1:0. I click Apply, OK, reopen layer properties ...
3
votes
0answers
130 views

How to fetch openlayers layers from pyqgis? [duplicate]

My objective is to fetch maps provided by openLayers, as in openLayers_plugin, from a stand alone python script. I would like to get it superposed to my shp file. As can be read on ...
0
votes
1answer
114 views

Can QGIS report/calculate areas/perimeters of individual polygon components within multipart shapefile?

Can QGIS report/calculate the areas/perimeters of individual polygon components within a multipart shapefile without using the "explode" vector tool to generate a new file? using QGIS 2.2.0 on ...
1
vote
2answers
405 views

Breaklines in QGIS interpolation plugin

How can I prepare data to generate a DTM using points and breaklines, but where every breakline has nodes at different heights. For example, a river valley, which regularly falls, or a dorsal line, ...
3
votes
2answers
1k views

How do I open images georeferenced in ArcMap in QGIS? (.aux.xml)

We have several ArcMap georeferenced images (raster datasets) that we are attempting to open in QGIS without any luck. These are not inside of a geodatabase and are not Arcinfo Binary Grid format or ...
0
votes
0answers
25 views

QGIS - unable to change projections [duplicate]

I am relatively new to QGIS (version! 2.0.1) and having trouble changing projections. No matter what I choose the view is the same. For example, in the attached screen shot I have chosen Alaska Albers ...
3
votes
1answer
142 views

Re-registering a GEOTIFF in qgis

I'm working on some images taken from a UAV over the course of a year. They are OSGB 1936 projection as is the whole project. Annoyingly they don't quite line up so I am trying to a few of the images ...
3
votes
1answer
269 views

Where is qgis getting the NO DATA value from?

I have a project that contains an 8-bit paletted layer (call it the mask layer) and a float 32 single band layer (call this the clip layer). I create a new raster by using the raster calculator, ...
1
vote
0answers
55 views

Error running SEXTANTE in QGIS on Scientific Linux

I've installed SEXTANTE into qgis on my Scientific Linux machine and I am getting the following when attempting to run Warp; INFO|Mon Feb 24 2014 15:56:20|GDAL execution console output|/bin/sh: ...
1
vote
0answers
62 views

How to get the signal when the color changes in pyQGIS?

I would like to have the signal when the color of a vector layer is changed by the user. In the doc, there is a signal that seems to fit ...
1
vote
0answers
52 views

“System not initialized. Programmer forgot to call G_gisinit().” message when loading table into GRASS via QGis

I am trying to load a CSV table into Grass with v.in.asciifrom the interface of Qgis 2.0.1 on Windows XP. As the progress bar indicated 74% of the data already loaded, I got the message "System not ...
3
votes
1answer
307 views

Qgis 2.2 how to fix bad epsg.wkt load

I installed Qgis 2.2 this morning from the ubuntugis repository for ubuntu precise. Qgis works great, except that all the common projections have been deleted. So, I am a Little bit having a heart ...
7
votes
3answers
1k views

How to configure QGIS and SAGA on Ubuntu (12.04 and others)?

During the past weeks, I have tried QGIS to recognize SAGA via the processing toolbox, both being installed from the ubuntugis-unstable repository. I have tried this on several virtual ubuntu ...
2
votes
1answer
38 views

Wrong sorting of elevation classes QGIS

I'm a totally beginner with QGIS and maybe I have a very easy problem, but I can't help myself. I got an elevation shapefile with classes of elevations like that: 1-100m, 101-200m, ... When I try to ...
3
votes
2answers
2k views

QGIS GISBASE specify location

I am just a beginner at this QGIS and GRASS and I am using this QGIS 2.0.1 Dufour which throws a error at the startup that "QGIS couldn't find your GRASS installation. Would you like to ...
2
votes
0answers
111 views

How to Simulate Venn Diagram of Buffers using QGIS?

For the sake of simplicity, suppose I have only 2 points on one layer. Point A have population of 100, and point B have population of 150. I do find buffer of these 2 points and it is intersect. I ...
1
vote
0answers
208 views

how to add polylines(routes from public transport) on postgresql(pgrouting) with GUI

After searching a several long time... i decide to ask here for help, im currently using ubuntu 12.04(because of compatibility) with postgresql 9.1, postgis2, pgrouting2 and qgis2.2 i need ...
3
votes
0answers
740 views

Move Scale Rotate raster in Qgis

I have some archaeological scanned raster that they have a north arrow and a scale bar. There is no grid, no coordinate system.I would like to put those files in a general map. I don't care about the ...
2
votes
2answers
426 views

How to write a new layer to PostgreSQL from QGIS plugin

The PyQGIS cookbook states that QgsVectorFileWriter can write vector layers to any format supported by OGR: https://www.qgis.org/en/docs/pyqgis_developer_cookbook/vector.html#writing-vector-layers ...
1
vote
1answer
180 views

Can I automatically save datetime for every entry in my spatialite tabel? [duplicate]

I'm using QGis and SaptiaLite. Is it pssible to store date and time in a field "datetime" for every entry automatically - maybe with some python code? Already existing datetime should not be updated. ...