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

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2answers
1k views

QGis problem with raster transparent

I am new to QGIS. I found the problem impossible to solve the parts of raster data that are in TIFF format should be made transparent. What do I do?
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0answers
321 views

Trouble getting lat/lons from point layer

I am following this post about how to get lat/lon information from a point file, but without success. Does this metadata posted below provide information that changes the prescribed method for ...
5
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1answer
443 views

Is it possible to perform 3D vector editing in QGIS?

I've searched the manuals and plugins and done some tests.. Is it in any way possible to perform 3D drawing and editing of vector objects for 3D mapping e.g. in a 3D shapefile or PostGIS 3D table?
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2answers
3k views

QGIS 1.8 will not start on Windows 7 [closed]

I have downloaded QGIS 1.8 and installed it on my windows 7 system. When I click on the desktop icon, nothing happens. I am currently running QGIS 1.7.4 with no problems and the installs of previous ...
4
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3answers
6k views

How to import info from mdb file?

I need to import info on a QGIS project. The info are in a MDB file (population, mean age, number cars and so on per Town) that is possible to connect with a region shape from an ID (the ID is the ...
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0answers
244 views

What do I need to build a C++ plugin on windows 7?

I want to make a plugin in C++ and I need to write and build it in windows (Im better with *nix systems). While I have skimmed the various updated C++Plugin docs I can understand if I need to build ...
6
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3answers
1k views

How to group elements in QGIS legend side by side?

I would like to edit the legend in my map so that the entries of two polygons will appear together, i.e. the two entries in the legend should be displayed appear as "Study area and possible study ...
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0answers
399 views

Importing GPS coordinates correctly

I am importing a gsx set of waypoints with lat/lon taken in degrees, minutes, and thousandths of a minute. When they are added to my project, the waypoints are not showing up correctly - the ...
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1answer
235 views

QGIS Updating composer label text via python - problem with Item Properties panel

I am writing a plugin that replaces the text of a composer label based on its itemID. When I change the text of the label using: item.setText("Hello World") the label changes on the composer but ...
2
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1answer
1k views

Convert area from square meters to degrees globally

I have a global raster file with 3600x1800 pixels. I don't have any information about the projection used. The raster contains one band with a quantity with the unit "per square meter". How can I ...
5
votes
4answers
7k views

How do I load a .dbf file into QGIS?

I want to use QGIS to extract lat/lng data from the vertices of polygons. There are about 400 polygons, each with maybe 200 vertices. I am having trouble with step one, getting the data into QGIS. ...
1
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1answer
3k views

QGIS Web Client installation procedure

I have QGIS Server up and running and can successfully load WMS layers back into QGIS. I am attempting to set up the QGIS Web Client. Procedure: https://github.com/qgis/qgis-web-client I am having ...
2
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5answers
2k views

Is there any way to extract coordinates of a road segment using QGIS?

I add my own road vector data on top of Google map using open layers plugin with QGIS. The vector layer is generated using PostgreSQL DB. Is there any way to extract coordinates of a road segment ?
4
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1answer
345 views

Looking for a SVG library for construction

Would anyone be able to suggest a good library for svg symbols for construction please? To be used in QGIS. Ideally water and pipeline network symbols. ciao
6
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1answer
548 views

PostGIS query vs QGIS filter

I have a PostGIS dataset with around 3 million shapes. I only need to view about 1,500 of these shapes at any given time, but the shapes I need to see depends on which feature is selected in a ...
2
votes
1answer
825 views

What happened to Live GPS Tracking in 1.8.0-Lisboa?

Dang, I was just getting used to Live GPS Tracking in 1.7.4-Wroclaw. I downloaded the new version 1.8.0-Lisboa on another computer. The Live GPS Tracking thing was in the View pull-down menu in ...
1
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2answers
1k views

Problem loading vector layer (pyQGIS)

I've installed the qgis on ubuntu 12.04 following the instructions on http://hub.qgis.org/projects/quantum-gis/wiki/Download. I am trying to test the Python API and try to do the follwoing from ...
3
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0answers
303 views

Freehand plugin query

I've installed the QGIS 'Freehand' plugin and I have a query regarding it. When drawing a polygon qgis automatically closes the polygon when the pen leaves the graphic tablet. Is there any way to ...
1
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2answers
918 views

How to access vector coordinates in GRASS GIS from python?

Is there a way to iterate over lines and their vertices using python? I'm new to GRASS GIS, and it looks like there are ways to read raster (for numpy), but I don't see a direct way to access ...
2
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1answer
1k views

Basic User Questions: Tracing a Border in QGIS

The project: I'm plotting a dilapidated cemetery, I'm using GPS waypoint data to plot the headstones in QGIS. The map I'm making is to show the orientation of the graves, and who is in them. I ...
3
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2answers
5k views

Calculating the minimum distance between points and polygons in QGIS

I have two vector layers: one point and one polygon and I want to calculate the minimum distance of each point from the polygons (ie the distance from the closest point of the closest polygon). Is ...
1
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1answer
925 views

Concatenate Fields into One Field in QGIS

I have seen some posts on this, but only for ArcMap. I am looking to take a range of values from two fields and concatenate them into one field to make a unique value. For example: XMAX YMAX ...
4
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1answer
868 views

How to reclassify in Rastercalc?

I now need to reclassify, I'm using rastercalc... but I can't get the syntax right!! I need that values >0 become 1 I found this example... eq( [relief]@1, [mask]@4, 150 ) so I tried: ( [raster A ...
5
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1answer
1k views

How to perform Ordinary Kriging in SAGA via QGIS SEXTANTE Plug-in?

I'm trying to learn how to apply the kriging analysis in QGIS using the SEXTANTE plug-in and SAGA tools. It appears that I have my SEXTANTE and SAGA folders configured properly according to the user ...
0
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1answer
225 views

How to find embedded Coordinate Reference system in a Layer

I want to find CRS in an added shape file. Ex. In Arc GIS if we go to Layer Properties and Source we can find embedded CRS to a layer. How to find in QGIS, embedded CRS ia a layer/ Shape file??? I ...
5
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1answer
2k views

Features to 3D from 2D in QGIS

Is there a way to convert 2D features to "3D" features in QGIS? I know there is a way to do this in ArcMap by using an attribute value in the attribute table, but I am looking to do this with ...
2
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1answer
214 views

How can i include program form (created in Designer ) to my QGIS plugin?

How can I include a form created in Designer in my QGIS plugin? And how to get controls values (textbox,label,etc)?
2
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1answer
1k views

How can I add button to the QGIS toolbox or create my own toolbox?

I want to create a button and add it to the QGIS toolbox or alternatively create my own toolbox and add the button here. A plugin should be started when the user clicks the button.
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0answers
2k views

download and installation of sample data [closed]

I have downloaded the sampe dataset under "my documents". When I extract the contents of the zip file, the only folders that are actually installed, are "gml", "gps" and "shapefiles". Thus, ...
0
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1answer
1k views

How to install sda4pp plugin with missing repository in QGIS

I see that the repository for the sda4pp plugin went down in 2011. Does anyone know if there is another way to download the plug-in with the repository missing? If this plug-in is no longer ...
2
votes
1answer
206 views

Can't load PYQGIS

I get this error; any comments Couldn't load PyQGIS. Python support will be disabled. Traceback (most recent call last): File "", line 1, in ImportError: ...
4
votes
1answer
158 views

Where are the Spatialite settings stored?

after moving a spatialite-database to another directory, qspatialite says "Can't connect to Database" / Error unable to open database file. Even no project is open or I try to create a new project. In ...
5
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5answers
9k views

How to break a single polygon into multiple polys?

I created voronoi polygons after which I dissolved them on the basis of one attribute. Now there are cases where in for one single attribute "abc" I have3 polygons at different places with same object ...
10
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5answers
2k views

How to identify duplicate attributes in a field?

I have a point shapefile with thousand of points. It has an ID code field that supposed to be unique. Every now and then the data entry clerk wrongly type the id creating duplicates.Right now I'm ...
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2answers
598 views

How to fix Error 14 — Unable to open ~/.qgis//qgis.db?

I get this error: Error 14 -- Unable to open ~/.qgis//qgis.db -- QGIS version 1.8.0-Lisboa -- Ubuntu 12.04 It was discovered when I tried to define a custom CRS and save it under: settings/custom CRS ...
9
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2answers
302 views

How do you protect your PostGIS credentials when using QGIS 1.7?

I'm fairly certain this should be a community wiki, but I don't know how to make it one. So if an admin sees this please change if appropriate. So.....How do you protect your PostGIS database data ...
3
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1answer
519 views

Correct ASTER with SRTM or Topographic Map

I have a problem with my DEM again. I decided to use ASTER GDEM2 (for different reasons). ASTER GDEM2 have its problems, I know, and I dont want to discuss that again. I have to use it, because SRTM ...
6
votes
4answers
1k views

How to sum up pixel values in QGIS?

I need to know the value of the sum of all pixels in a raster. However, in the Statistics section of the Metadata tab in Properties, under Sum of All Cells it always indicates 0.00. I have tried with ...
1
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1answer
173 views

Looking for CRS for NAD 83 UTM Zone 30N

I'm curious as to why the UTM zones are incomplete for NAD 83 in QGIS? I have a WGS84 shapefile that I would like to project to NAD83 UTM Zone 30N but can't find it in the QGIS CRS list. I see how ...
3
votes
2answers
1k views

How can I specify the CRS of a raster layer in pyqgis?

I manipulating netcdf raster data from the QGIS python console. The metadata of my netcdf file does not provide the Reference system. However I know it is 'EPSG:4326' I am writing a python script to ...
5
votes
1answer
1k views

How to fill my column with consecutive numbers

I m very new to Qgis, so forgive this simple question. Searching in older topics didn t help either.So: I make a new column in my attribute table and it has a default value(for example 0). I want to ...
1
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1answer
1k views

How can I create a custom form to display the attributes of the selected object?

I have already appealed to the selected objects, and found a way how to put them in a MsgBox. But I need to output was in the form
4
votes
2answers
495 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 ...
1
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2answers
453 views

How to batch process (100s) of interpolations in QGIS or other open source software programs?

Is there an efficient way to run 100s of interpolations in QGIS or other open source software programs? I have groundwater contamination data collected from monitoring wells at about 800 different ...
3
votes
1answer
207 views

How to calculate maximum distance to an interpolated value along a contour in QGIS?

I'm planning to enter concentrations of groundwater contaminants collected from well locations into QGIS and then use interpolation functions to create contours of the groundwater plume. Can QGIS ...
6
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1answer
122 views

Finding Ring Smaller than a certain tolerance

In Simplifying a shapefile for world timezones http://efele.net/maps/tz/world/ all generalize/simplify algorithms fail on 5 countries/states, shown in this shape file ...
3
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1answer
146 views

How to display a particular area?

Hy, I'm developing a plugin in python for Qgis. I would like the user to select a particular area in a list (let say a country list) and zoom in the map on the corresponding area. Actually I'm ...
0
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1answer
183 views

Qgis : QGraphicsTextItem's position not updated?

I'm using QgisInterface->mapCanvas()->scene()->addItem(QGraphicsTextItem) to add a QGraphicsTextItem to the map canvas. The problem is that when I use the pan tool to move the display the added ...
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0answers
62 views

How can I create form with controls using QGIS(python)? [duplicate]

Possible Duplicate: How do I build a custom form for entering attributes in QGIS Help me, please create a form with controls using QGIS plugin. Thanks!
5
votes
2answers
5k views

snapping polygons and lines

I recently downloaded QGIS on a Mac OSX 10.7.4 (lion) and purchased a master map shape file, of a particular area. I am trying to divide it into polygons following features on the master map vector ...