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

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7
votes
2answers
2k views

How to use Heatmap plugin and its output?

I have a layer of points which I would like to depicted as a heatmap concentration of points for visualization. In QGIS 1.8 I tried the built-in heat map plugin, leaving the default values as is, and ...
0
votes
1answer
1k views

How to generate smooth contours from cropped raster?

I’m trying to create contours from a raster layer in QGIS. On my first attempt, I cropped my raster layer in Photoshop and reimported it, but it lost coordinate data I think. I made the contours ...
5
votes
1answer
4k views

How to crop raster layer?

Can anyone tell me how to crop a raster layer in QGIS? I want to make contours from a section of a layer, and including the whole layer will create far more data than I need and slow down the ...
1
vote
2answers
151 views

How to select only areas bigger than x acres?

I would like to create a new shapefile from another area shapefile. The new shapefile should only contain all areas that are bigger than 5 acres (10.000 m²). How do I do this?
2
votes
1answer
108 views

Generating plan sets using different layer configurations

I am working on a flood modelling project that will generate a very large number of plan sets. Each set will have several plans - say a general arrangement plan and say 5-10+ sheets tracking along a ...
1
vote
1answer
208 views

Spatial Query plugin broken in MacOS version?

I'm running QGIS 1.7.4-4 on a MacOS 1.6.8. I'm trying to use the "Spatial Query" plugin but it's not loading. The plugin is activated and I can see it in the main menu Plugins > Spatial Query > ...
3
votes
0answers
2k views

How to load and view .gri and .grd files in QGIS [closed]

An online GIS Repository called DIVA-GIS (http://www.diva-gis.org/gdata) offers data in three formats - ERSI files, "DIVA gridfiles", and DBF files The DIVA gridfiles have extensions .gri and .grd ...
0
votes
1answer
255 views

How to remove polygon under other one?

Hi, lets say that green polygon is under red and part of blue with yellow stripes is also under red polygon. how can i make one polygon from every polygons that intersects my main ( red ) polygon ...
1
vote
1answer
3k views

Why can't I right click -> toggle editing Quantum GIS [closed]

I would like to delete multiple polygons at once: How to delete multiple selected polygons at once? Why can't I right click -> toggle editing Quantum GIS [ it is grayed out] ? My layer is polygon ...
2
votes
5answers
3k views

How to export labels to DXF file?

Is it possible to export labels based on Shapefile attributes into a DXF file? I use Quantum gis in Version 1.7.4. I've been reading a CSV file and view it as a Shape Layer. With the help of ...
6
votes
3answers
323 views

Real-world QGIS users [closed]

I am just beginning as a QGIS user, and I have used ArcGIS mostly in the past. I am in the position of having to defend QGIS as a viable solution for many, if not most, GIS needs for Country and City ...
2
votes
2answers
701 views

How to calculate a new raster based on nodata values from original raster, in QGIS?

I'm using the raster calculator from core in QGIS and I need to generate a new tif raster file (mask) from the nodata values of another tif raster file. I tried isnull(), but no luck. Any one can ...
3
votes
2answers
328 views

How to achieve Activity Sizing in QGIS

I have plotted 30,000+ points in QGIS by postcode, various data items for each. How do I resize these plots based on the activity at each of these points i.e. small dot for <100, larger dot for ...
4
votes
4answers
755 views

How to automatically plot intermediate contours with QGIS, GRASS GIS or SAGA GIS?

I'm mapping a steep mountain range. My main contour interval is 50 m and my intermediate contour interval is 10 m. In steep areas, the interval of 10 m is too small, so I need to leave ...
2
votes
1answer
282 views

How to port QGIS C++ plugins to other QGIS installations?

I developed a C++ plugin for QGIS using VC++ express 2008 and a QGIS dev release (1.9.90 alpha), my plugin works fine on this release and now I want to port it to other QGIS installations, so I copied ...
2
votes
1answer
279 views

Conversion of ASTER GDEM data for CFD Analysis

I need to do a computational fluid dynamics (CFD) analysis of wind over a large area of land. I have obtained the necessary tiles from the ASTER GDEM data set (in .tif format) and was wondering how I ...
1
vote
1answer
166 views

Open --> Setting --> Project Properties will shut down Qgis

When I want change my project and I select setting and the project properties . It's will give me some message, like "Exception - Bad allocation" How do fix the problem ? http://imgur.com/XEHcs
2
votes
1answer
414 views

How to solve postgreSQL error when using QGIS Cloud plugin?

I created a qgis cloud account and installed the plugin. When I attempted to Upload Data using the plugin, I got the following error: postgreSQL exception: ERROR: "MD5" authentication with pgpool ...
-3
votes
1answer
739 views

How to connect QGIS with Visual Basic?

I'm an final student at one university, i need to make one project to make web based GIS application using open source. I select Quantum to make this project. Here i want to ask anyone, how to connect ...
3
votes
1answer
280 views

Is there a way to export labels in QGIS?

I've used the v2 labeling engine to place some nice looking road labels. Now I'd like to export those labels as a point shapefile for use in another program. Is there any way to accomplish this?
2
votes
1answer
2k views

How to open or import .sdc files in QGIS?

I have some .SDC files i want to look at but i dont have arcview installed. is it possible? i couldnt even find a software that does sdc to shp conversion. any idea? i am using qgis 1.7.4 on both ...
0
votes
2answers
159 views

Need to hyper link my personal data to a shape file [closed]

I want to hyper link my personal data like excel file to a shape file. Can I do it in QGIS. Kindly help.
1
vote
0answers
347 views

error while trying to compile quantum gis: unresolved external symbol class QgsSearchTreeNode

i'm trying to compile the quantum gis sources code following the step by step how to compile guide, but i'm facing an error when code is linked. I'm compiling in Windows 7 x64 in Microsoft Visual ...
7
votes
4answers
2k views

How to close watermarks window in QGIS Openlayers plugin?

I'm using Quantum GIS Ver. 1.7.4. I have upgraded openlayers plugin 0.7 to 0.9. However when I open google satellite, a watermarks/copyright dialog box "Data Peta@2012 ..." appear in the middle of the ...
0
votes
0answers
21 views

MapCanvas : Mouse-wheel event filtering/overriding [duplicate]

Possible Duplicate: MouseWheel event filtering on Qgis I’m developing a C++ plugin for Qgis and I want to filter/override the mouse-wheel event. I created a “maptool” to select a polygon ...
2
votes
1answer
392 views

How to convert decimal point to comma in QGIS?

I am working with data in Colombia where decimal points are written as commas. I would love to create a new column in QGIS that would convert all decimal points (periods) to commas for the purpose of ...
3
votes
1answer
280 views

How to move Layer to back?

from my Plugin I've loaded a rasterlayer using the following code: fileName = "/path/to/raster/file.tif" fileInfo = QFileInfo(fileName) baseName = fileInfo.baseName() rlayer = ...
3
votes
1answer
108 views

Is there any extension to “optimize” the creation of maps in QGIS?

is there any extension to "optimize" the creation of maps in QGIS? i searched the repository, but found nothing useful, maybe i searched in a wrong way.. there are some things i am really missing: ...
5
votes
2answers
441 views

How to filter the MouseWheel event in a QGIS C++ plugin?

I’m developing a C++ plugin for Qgis and I want to filter/override the mouse-wheel event. I created a “maptool” to select a polygon feature on a vector layer, the feature has two attributes : an id ...
1
vote
1answer
540 views

Join attribute table

I am using QGIS 1.7.3 on Mac and when I try to use the tool "join" in the properties toolbox, I have no possibility to add a name for either the file or the field used to join tables. Has anyone ...
5
votes
1answer
546 views

How to calculate Line Density in QGIS?

I have a map of fracture distributions over an area and I would like to calculate the density distribution of fractures that intersect a moving window with a specified radius. Is there a way to ...
7
votes
3answers
5k views

How to speed up working with QGIS or is it slow?

I am a new QGIS user and I am curious about how slowly it is performing; it is possible that I'm asking more of it than I think I am. Here's what I think is the relevant information for assessing ...
1
vote
2answers
428 views

How do I batch export maps for sub regions of a dataset with qgis?

I have a national level dataset consisting of polygons, polylines, points and rasters. I would like to export a map for every sub region (border defined by a polygon shapefile). Is there a simple way ...
2
votes
0answers
76 views

Is there a way to link eVis with time manager in QGIS

I have a point vector layer created from way points of a GPS. I then used the eVis plugin to view geotagged photos for each of these point. I also used the time manager plugin to play through the ...
6
votes
4answers
4k views

How do I convert a polygon into a point?

I want to convert polygons into points. I know how it's done in ArcGis and I think this may sound trivial but it's a serious issue :/. I'll appreciate any hints :)
2
votes
1answer
2k views

How to correctly specify coordinate system?

Using QGIS v. 1.9 (1.7 does not seem to be available for Ubuntu Linux 12.04), do the following: Create new project, specify coordinate system by clicking on button in bottom right hand corner, ...
4
votes
1answer
334 views

Can I create a legend of a map that I had get from a WMS?

Can I create a legend of a map that I had get from a WMS? Can I create a legend of a raster map with Qgis version 1.7.4, or only with the 1.8 version?
15
votes
3answers
3k views

Visual Impact Assessment in QGIS or GRASS

Is it possible using QGIS or GRASS to perform a Zone of Visual Impact assessment? E.g. where can a 100m high structure be seen at a viewing height of 1.8m within 30km, taking into account elevation ...
4
votes
3answers
1k views

Where is the Heatmap Plugin

I have read the questions about creating heatmaps but I cannot find the Heatmap Plugin in any of the repositories or using the fetch python plugins, it simply is not there. Could someone please tell ...
4
votes
5answers
5k views

Why can't I add most plugins under Ubuntu 12.04?

I loaded QGIS into 12.04 with much trouble but it works. Although I do not seem to be able to load most plugins. I go to fetch plugins and most are not loaded so I try to load some and they will not ...
2
votes
2answers
1k views

1'' DHM: Hillshade is too rough - how to “generalize”?

I got this hillshade from my DHM (I used the hillshade-module from qgis). For my purpose there is too much relief detail (roughness). How can I get rid of this in QGIS or GRASS? Thanks! Martin
3
votes
1answer
1k views

How to prepare or normalize raw shape (.shp) files for Openlayers use

Hi all it seems like I am having difficulties in normalizing raw map files' resolutions to openlayer's use most probably in parameters mapext and imgext. I hope you can help me with this. Using raw ...
1
vote
2answers
10k views

How to convert coordinates from meters to decimal degrees?

I have a shape file. The coordinates (Lat/Long) are projected as meter (555000, 155000). But, I want to re-project it to decimal degrees(51.523666, -0.07467). How can I do it with ArcMap or Quantum ...
1
vote
1answer
745 views

Why does QGIS Profile from Line tool give me the same value for every point?

I'm trying to make an elevation profile with QGIS's Profile from Line plugin. But when I do, the resulting points all have the same value: -32,767. I'd like to know what I'm doing wrong. My elevation ...
1
vote
1answer
3k views

QGis 1.7.4 on Ubuntu 12.04

Will there be available stable version of Qgis 1.7.4 in Ubuntu 12.04? Version 1.9 is working fine at the moment, but as it is unstable yet, dont want to risk with my work. Thanks.
5
votes
1answer
7k views

Adding Layerfiles (.lyr) to QGIS?

At college we use ArcGIS Desktop 10, but that does not function on my Mac so I have QGIS there instead. I want to do my exercises with QGIS, but we use .lyr files with ArcGIS Desktop, and they are ...
3
votes
1answer
990 views

How to create a Hillshade model with multicolor “alà IMHOF”?

I would like to make a Hillshade-Model with multicolor "alà IMHOF". That means, I dont want a "usual" gray hillshade, I would like to use grey-blue and grey-violett from different sun directions. ...
3
votes
1answer
243 views

How to join interrupted river lines?

I have a vector map that I converted from a raster, representing the rivers in the map. However, because the colours in the map were very diffuse, the resulting vector map has many interrupted lines. ...
5
votes
3answers
2k views

How to create a user map from CSV?

I dont even know if QGIS is the right program for what I need.. What I need: I need a program with maps(Denmark to be specific), that I could feed with a database of users through a CSV file.. e.g. ...
9
votes
2answers
5k views

How to add Direction and Distance to attribute table?

anyone who can help. i just want to add direction (Bearing: i.e N 25 35 E) and Distance (Length: 125 meters) as my new field in polyline/line data. is there a plug-in to generate these fields? i tried ...