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

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4
votes
1answer
628 views

Unit of $length in QGis Field Calculator

I'm calculating field of various features in my shapefile using QGis. I'm getting some sample length as 0.134914579766986. I want to know in what unit (eg: meters, km etc) is the above value ?
4
votes
1answer
856 views

Is there a silent installation command without the desktop shortcuts? [closed]

I installed QGIS with Microsoft SCCM 2012 and I want to make a silent install without desktop shortcuts. I managed to do a silent install with / S but I found no s command to delete desktop ...
4
votes
4answers
676 views

TIN interpolation crash in Qgis

I have problems using the function TIN(linear) interpolation in Qgis. The program crashes when larger areas is interpolated. Map properties: vector map, Geometry typ = Point, features in this ...
4
votes
1answer
1k views

Qgis - How to change GDAL version

im working on Ubuntu 12.04 server; i noticed this when i installed additional support for ECW format into the GDAL 1.9.1 which worked ok. Then i tried to add ECW files to Qgis but it said they still ...
4
votes
1answer
2k views

Performing Geoprocessing SQL Queries in QGIS from a PostGIS Database

This may be a dumb question, but is there way to run a PostGIS geoprocessing SQL query in QGIS? Specifically, I am thinking of running SQLs such as ST_Union, ST_Split etc etc. I have tried the ...
4
votes
2answers
491 views

How to represent an imaginary flat world in QGIS without using a round-world CRS

Like one or two other users, I'm interested in using QGIS to map an imaginary flat world. A previous answer suggested simply refraining from defining a CRS for such a world, but I cannot seem to make ...
4
votes
0answers
368 views

Map is missing when I “export as image” via print composer [closed]

I have point data on a vector layer that prints accurately via print composer (when I "export as image"), however my map below either does not show up or shows up at an incorrect scale. I used ...
4
votes
5answers
804 views

Elevation correction ASTER GDEM2 (+10m)

My ASTER GDEM2 has a average elevation error of -10m for my area. (I testet it using 90 defferential GPS reference points and compared it with old Topo25, SRTM, and GoogleMaps). I would like to ...
4
votes
4answers
3k views

How to import qgis.core to python app?

I'm new to Python. I want to create GIS app with Python using QGIS library on Window 7 64bit. The way I do: install QGIS 1.7.0 I set PYTHONPATH=D:\Program Files (x86)\Quantum GIS ...
4
votes
2answers
455 views

How to fix a raster with wrong Eastings?

I get an error when trying to warp a tif file in QGIS: ERROR 1: Too many points (35721 out of 35721) failed to transform, unable to compute output bounds. I am using QGIS 1.7.0 Wroclaw with gdal ...
4
votes
3answers
762 views

How to place multiple symbols on one polygon centroid?

I am using QGIS for visualizing the health conditions of elderly living in an old age home, some of the elderly have multiple medical device with them and I want to show them on the map. Suppose I ...
4
votes
1answer
794 views

Can QGIS resample Rasters during display?

When I was using ArcGIS a user could resample a raster during the display (I think via layer properties under the display tab). This would smooth the appearance of the raster so it wouldn't appear ...
4
votes
2answers
745 views

Plugin for average distance from node to polyline in QGIS?

Is there a plugin available that will calculate this? EDIT 1: The red polyline is the average distance of the point to the black polyline. The red polyline is what I want to display. Alternatively, ...
4
votes
2answers
4k views

How do you Turn on the Grass plugin in Quantum GIS?

I downloaded and installed Quantum GIS 1.5.0 with Grass using the OSGeo4W installer on my XP machine. Unfortunately, when I go to Plugins>Manage Plugins I cannot find the Grass plugin. When I browse ...
3
votes
2answers
54 views

Correlation between a raster and a point dataset

I have an interpolated surface (in raster form) with temperature values and I also have the measurements of temperature in certain locations that belong to the same region (with the raster). I want to ...
3
votes
2answers
153 views

How to set NULL as default value for a date field in QGIS 2.4?

In QGIS 2.4, i am unable to set the default value as NULL if i have not updated any value on date fields. Its automatically taking the current system date. I am expecting to set the default ...
3
votes
1answer
73 views

Is it possible to rotate the *canvas* in QGIS

Can the canvas be rotated so north is pointing in some other direction than defined by the projection? This question answers with respect to the composer, but not the canvas. There is a related 5 year ...
3
votes
2answers
144 views

Combining MS Office with GIS

I would like to incorporate MS Office into my GIS program. I have been using QGIS and was wondering if this would be possible? I am trying to create a one stop shop for my staff to be able to ...
3
votes
2answers
329 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 ...
3
votes
1answer
236 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 ...
3
votes
1answer
208 views

Load and display a layer using PYQGIS

I'm having a go at using pyqgis from within the QGIS python console to load a layer from SQL Server and display it. I feel like I'm part way there but I'm having a real issue getting the layer to ...
3
votes
1answer
195 views

How to display an elevation profile and store the DEM elevation back to the KML line?

When I draw a track in Google Earth, for example along a road, I can right-click it to "Show elevation profile", and it displays a 2D plot of distance vs elevation. However, if I save the KML, the ...
3
votes
1answer
65 views

How to create a printable data sheet when using edit widget “value realtion” in QGIS 2.0?

I created a spatiaLite Database with a point layer (every point is a tree). Additional I created several tables to fill the columns of the spatial layer with attributes using the editing widget “value ...
3
votes
2answers
275 views

Ortho Projection produces artifacts

I`m trying to create a sphere-like view using qgis and the "world from space"-projection http://spatialreference.org/ref/sr-org/6980/ (essentialy an ortho-projection). ArcGIS wraps the shapes ...
3
votes
1answer
241 views

How to create DEM from contours without ArcGIS Spatial Analyst licence?

I'm trying to create a 3d DEM/DTM from a flat contour shapefile which has height data attached to each contour, but I'm not sure how to do this? I've found this post, on creating a dem from contours ...
3
votes
2answers
235 views

QGIS DB manager Import layer/file tool won't allow me to choose “Append data to table”

I want to append some data to a layer in my PostGIS DB using a shapefile, but when I use the Import layer/file tool in QGIS, it doesn't allow me to choose the append option. Why is this and how do I ...
3
votes
1answer
1k views

Why can't I edit attribute table imported through 'text as layer'

I imported the coordinates from an Excel table. They show as single points as intended. Now I want to add columns to the attribute table, but I'm not able to edit it. I wanted to import the following ...
3
votes
2answers
626 views

How do I create a shapefile of polygons from points in a spreadsheet?

I have a spreadsheet that has 100 different polygons listed with UTM coordinates for the 4 corners of each polygon. I want to turn the spreadsheet into a shapefile with 100 unique objects, 1 for each ...
3
votes
1answer
274 views

KML in QGis with additional Data [closed]

i´ve developed a android app that extracts the exif-information of a photo and creates a KML-file (Placemark) - some additional information like camera-type, focal length,... are stored in the tag ...
3
votes
2answers
194 views

How do I export XY data from QGIS to shapefile?

How do I export XY data from a comma-delimited file to a shapefile using QGIS?
3
votes
2answers
252 views

QGIS 2 problems with Plugins

Rough English (Translated by a user): When trying to access plugins I am told Unable to open the Python console. When I start qgis, the message also shows up but I don't know what it means. ...
3
votes
2answers
436 views

How to group and count attribute data?

I have a problem with group same data to count it. for example, i want to group same code to one and count them. i can do it when i use MapInfo (Pic 1) but i can't in QGIS. (Pic 2: i can classify ...
3
votes
1answer
94 views

Field Value Mapping QGIS

I am wondering if there is a way to do field value maps that are filtered based on another attribute field? I know how to associate value maps, but not that are connected to another field. I have ...
3
votes
2answers
397 views

How to do a Point to Polygon analysis with multiple variables?

I have a database of almost 10k crimes, which are divided in to 10 categories and plotted on a map I also have a database of 12k addresses, which are also plotted on the map. I aim to perform a ...
3
votes
1answer
301 views

Invert Color Ramp in QGIS

This is a real basic question, but I can't seem to find it. How do I invert the color ramp in QGIS? I am using RdYlGn, but I would rather use GnYlRd. Seems really easy, but I can't seem to find ...
3
votes
5answers
449 views

How can I count overlapping polygons, resulting in a new set of polygons?

I have 100 polygons in a GeoJSON file that partially overlap each other. I would like to produce 100 new polygons as follows: The area covered by any of the original 100. This is their union. The ...
3
votes
1answer
79 views

How to tell the size of grid cells created by the vector grid tool?

Im working with qgis 1.8.0 and Im making a vector grid on a map. Does someone know how big are the squares if the grid settings look like in the picture? Thanks for your time!
3
votes
1answer
175 views

Divide shapefile

I'm new working with QGIS 1.8.0 and wanted to know if its possible to subdivide a map (shapefile, which is round-like) into small squares but following the outer round contour of the map? I tried with ...
3
votes
1answer
611 views

How to add CSV data with no coordinates to a polygon layer in QGIS?

I would like to add attributes from an spss database (around 300 cases) to a polygon layer in QGIS. Both datasets have a column with unique IDs. I exported the spss data to a CSV file which does not ...
3
votes
1answer
352 views

How to add complex Emergency Symbology (TrueType fonts) to QGIS?

In other packages I would simply ensure the TrueType font (+.ttf) was loaded on the operating system and it would be available for use. QGIS seems to rely on making your own. The symbols I wish to ...
3
votes
2answers
378 views

How to average values in a point layer with respect to polygon layer in QGIS?

I am new to GIS and have the following problem: I have 2 layers: a point layer with a column that contains numbers (pollution index from specific measurement point) and a polygon layer with different ...
3
votes
1answer
184 views

Masking/removing polygons from shapefile

I have a shapefile containing the road traffic noise of a city. The shapefile has 5 columns, where 'noise_in' (noise interval) ranging from 1-5 is included. I want to remove/mask the road noise from ...
3
votes
1answer
862 views

How does Flow Mapper Plugin work?

I downloaded the Flowmapper plugin for Qgis and I can't seem to find any information on how it is supposed to work... Also the text seems to cut-off and not fully showing for the input fields so I'm ...
3
votes
2answers
959 views

How do you change the editing capabilities on a MapInfo .Tab file?

When I load a .Tab file into QGIS I am unable to make changes to it. The information on the MetaData Tab reads the following: "Editing Capabilities of this layer: Add Attributes, Fast Access to ...
3
votes
2answers
132 views

I am unable to draw a shape layer

When I add a new shape layer or want to edit an existing one, nothing is happening. I even don't see the dots where I'm clicking. Maybe the problem is I deleted some layers (by opening the .qgs as a ...
3
votes
2answers
213 views

Layer not aligning after georeferencing using BC Albers

I'm currently having trouble with the georeferencer... after what appears to be successful georeferencing, the map image layer does not align to the vector data. I'm trying to use BC Albers ...
3
votes
1answer
944 views

How to convert jpg file to shapefile? [duplicate]

I am developing a GIS application like this: By now my steps are: I have got a jpg file, 5040 x 8179 dimension. In this map, the roads, rivers, towns etc. are marked. I am using .Net to develop ...
3
votes
1answer
1k views

How to install SciPy for QGIS Standalone [closed]

A number of QGIS plugins require the Python package SciPy to be installed. This package is available using the OSGeo4W package based installer or precompiled for Windows, but is not provided as part ...
3
votes
4answers
946 views

What are the advantages either way between GML and ShapeFiles?

After a good start many months ago of getting into GIS through QGIS, I had to drop what I was doing and did not touch it for quite some time. I am now able to get back into it and have a need to load ...
3
votes
1answer
279 views

How can i merge lines with same name and intersect each other?

I have shp file with 50k lines (roads). Many roads have same name like 'high road' . some of them are the same road (they intersect each other) and some are located in different places of the city. I ...