Questions tagged [qgis]

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

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156 views

Error in my buffer plugin

In my buffer plugin, i tried the following code # Get buffer distance and selected city dist = float( myLineEdit.text() ) city = myComboBo.currentText() # Get the feature corresponding to the ...
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154 views

How to project the geographic grid in a shapefile in QGIS

Is it possible to automatically project the geographic grid (View -> Decorations -> Grid) into a shapefile layer in QGIS?
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51 views

How to georectify a fictive earth to a projection-less version

I have a picture of a fictive earth-like world. Now I would like to draw the outlines and then georectify this to a projection-less version. I really need the map unrectified. Because I want to ...
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111 views

Query does not work on joined file

Using QGIS 2.6.1 Brighton on an IMac (10.8.5). QGIS 1.8 Lisboa with exactly the same two vector shapefiles and the same CSV file works. I joined the file containing the polygons showing the features ...
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236 views

QGIS Mac OSX version cannot batch write output files after rasterization

I have been trying to batch rasterize a series of .shp files using QGIS for Mac OS X, and keep coming up against a strange problem. I am using the QGIS 2.6.1 user interface, rather than calling ...
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242 views

Finding census block with highest pop. value within census tract using QGIS?

In QGIS, I'm trying to plot a centroid of only the census block with the highest population within each census tract. So there should only be one point per tract- that of the block with the greatest ...
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2k views

Mapfile generation from QGIS project

I am looking for a way to transform a QGIS project (.qgs) to a MapServer Mapfile (.map). I am using Quantum GIS 2.6 and MapServer 6. The layers are postgis tables. I would need something like this ...
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323 views

Alignment by expression is not working after using “wordwrap” instead of “wrap on character”

I'm using wordwrap in the expression dialog to wrap the field "name" after the 12th character (first line) and the 20th character (second line): wordwrap( wordwrap("name"),12),20) So far so good. I ...
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622 views

Multiple Labels from attribute column in QGIS

I was wondering if there is a way to have multiple labels from a joined attribute table in QGIS. I have two tables, a polygon table, and a table with words (codes). The codes table can be joined by a ...
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952 views

Export to Oracle using QGIS

I have loaded a shapefile into QGIS and I now want to export it into our Oracle Database and add SDO_GEOMETRY. Is it possible to do this directly in QGIS? If not, what opensource options do I have to ...
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2k views

Moving labels with “easy label engine” tool of QGIS

I am using QGIS 2.6 and looking for an similar tool like "converting label to annotation" as you can find it in ArcGIS Desktop. The "easy custom labeling" Tool in QGIS seems to come close to the ...
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161 views

QGIS raster symbology problem in 2.6

With the new 2.6 QGIS version I often have problems with raster colors. For some reason certain pixels do not display initially, but if I move the raster a little spatially they show up.
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1answer
122 views

Making map use set of coordinates in QGIS

I have made a custom google map with the google map api which has a few functions that work well within it - one specifically is limiting the user on what they can view within the bounds of the map. ...
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118 views

QGIS vector edition corrupts SpatiaLite attribute table

I have a problem with edit SpatiaLite Layer on QGIS. When I make a this set of editions: cut line, delete a part, insert a new line and save it, the attribute table is corrupted. I was thought that ...
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305 views

DB manager not updating

I'm trying to learn how to use spatialite databases, so have made a few experimental ones. When I delete them, however, they still show up in QGIS's DB Manager. If I try to open them it comes up with ...
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268 views

What happened with NVIZ?

I'm unable to find and run NVIZ and now I've read several places that it's not functioning in the latest versions of QGIS? Is this a temporarily bug or definite?
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155 views

GDAL_Translate not compressing when NoData value is set

I am trying to compress a .TIF file using GDAL_Translate or GDAL_Warp. My Raster is 32mb to start with. When I use GDAL_Translate with the COMPRESS=PACKBITS option, it compresses to 1.9mb. However ...
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197 views

Rotate polygon preserving topology in QGIS?

Is it possible in QGIS? What I need is: 1) Rotate a polygon inside another one (bigger), obviously the polygons are not overlapped. 2) Rotate a given polygon in a topologically correct layer (like a ...
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641 views

Polygonizing only pixel values of 1 from raster using QGIS?

I have a raster mask that I have created in QGIS (2.2.0) that consist of 0, 1 and nodata values. I would like to end up with a polygon dataset that consist of only the value of one pixels from this ...
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300 views

Standalone QGIS application - handling QgsVectorLayer load errors

I am creating an application with QGIS libraries, and in the event that the app can't add a specified layer (e.g. no connection to host, no password specified etc), it causes the app to crash, ...
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665 views

Why can I not publish from -QGIS Geoserver plugin?

I am following the tutorial at http://qgis.boundlessgeo.com/static/docs/quickstart.html and I get to the step "To publish the project as it is, just select the QGIS project entry in the OpenGeo ...
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2k views

PyQt resources file to display images on QGIS custom feature form

I am having issues creating a PyQt4 resources file to display images in my QGIS 2 custom feature form using Windows XP. EDIT This still gives me problems with windows 7 on 32 and 64 bit machines, so I'...
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1k views

How to calculate a population weighted centroid using a raster and shapefile in QGIS?

I am very new to QGIS so please help me with a step by step answer. I have a raster file with population count and a shapefile based on a large population and shapefile. I have successfully created ...
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141 views

QGIS Fill Ring tool problem

Using the new (in 2.2) 'Fill Ring' tool and it doesn't seem to work correctly in all cases. It seems that if I try and digitise the new ring close to the polygon boundary, TWO (or more) geometries ...
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137 views

Open Source .Net GIS software end-to-end

I need to provide a client with an end-to-end web-based GIS solution running on IIS. I will admit to not knowing much about the subject, other than having developed a Google Earth enabled version of ...
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326 views

PyQgis: How can I preserve order or index when adding features to a Vector Layer from a file?

As I read data from a text file and add points to a QgsVectorLayer (as well as related attributes), each new record gets 'stacked' on top of the previous one in the Attribute Table (and within the ...
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191 views

Slope regions from elevation points using QGIS 2.0

I am using QGIS to create a layer of slope region polygons (e.g. less than 30% slope, 30-50%, more than 50% categories). My data comes from point elevations and I interpolated using SAGA b-spline ...
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220 views

Issues creating slope raster layer from a point layer

I'm trying to create a slope raster layer using QGIS 2.0 on Windows XP. I started with a points layer with the Z elevation attribute. I then used the interpolation plugin to create a DEM. But, ...
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133 views

Error 14: Could not open CRS database

I am using Python Console and loading a Vector Layer using python commands. When the layer is added, QGIS first asks for the CRS to use, but I don't have all the CRS listed out to select the Reference ...
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701 views

MODIS images set CRS and reproject

I am developing a plugin which reads MODIS images, and I know that MODIS images are in sinusoidal projection and I need to set that CRS and project the image to WGS84 (epsg 4326) in python. I search ...
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951 views

Mapnik: GeoTIFF flipped (mirrored vertically)

I generated a GeoTiff using the QGIS HeatMap plugin and want to render it on top of some OSM data. The problem is that the raster gets rendered upside-down in the output. Can someone point me in the ...
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312 views

Using iface.showAttributeTable() on QgsVectorLayer retrieved by getObject()

I'm unsure if i'm properly using the processing.getObject() function. I'm creating a python processing script for QGIS 2.0 and 2.2, but can't seem to get an attribute table to open programmatically. ...
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135 views

QGIS - Atlas. Outputs missing

This really teases me. Somehow the Atlas-function in Print Composer are missing some of my polygons from my layer, when doing a print. I´ve looked at them once again,- they are there, and the geometry ...
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126 views

Why can't I save a line shapefile?

I'm working with qgis v. 2.0.1. I have some data points and I just wanted to create a new shapefile with line geometry. In the new vectorlayer-window, I added some attributes (approx. 10) and klicked ...
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165 views

Delayed moving average

I want to develop a plot of delayed moving average. The code for this in MATLAB is: nr_pontos = 36; coefs_filtro = ones(1, nr_pontos)/nr_pontos; data_dma = filter(coefs_filtro, 1, data); figure,plot(...
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67 views

Rings not displaying on .TAB import to .SHP save

I have some strange behaviour happening when importing a MapInfo .TAB file into QGIS. One feature contains internal rings which are ok on initial import but do not show on the first .SHP save. I can ...
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513 views

QGIS: Albers projection in lat lng?

I'm trying to make a map of Russia in the Albers projection. My projection string is: +proj=aea +lat_1=45 +lat_2=70 +lat_0=40 +lon_0=100 +x_0=20 +y_0=20 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m ...
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128 views

Cropping elements from one layer to an element from another

I'm trying to make a hex map of a country (Russia, in this case). To do this, I've opened a map of Russia in QGIS (from Natural Earth), set up my projection, and created a hex grid with MMQGIS. So far,...
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260 views

Viewer functionality in QGIS?

Is there a viewer function/display in QGIS as it is in ArcGIS. Or is there an other possibility to limit the access (just visualisation, no analysis)?
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146 views

Export additional data with ogr2ogr

I am trying to import my ESRI-shapefile with OGR2OGR to an existing mysql table. This works fine but unfortunately only the featureID and the geometry data is exported. How do I add the labels of the ...
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67 views

Should OGR2Layers plug-in respect layer transparency?

When I export a graduated style layer from QGIS Dufour to OpenLayers using the OGR2Layers plug-in and QGIS rendering the colors and categories come across correctly. However, the opacity in the HTML ...
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914 views

export from .shp to .gpx and .kml fails

I've just upgraded to QGIS Dufour and I am having some problems with the exportation of a simple track from .shp to .gpx and .kml format. I imported from mi smartphone a .gpx track (SR WGS84 EPSG:4326)...
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730 views

Why does my QGIS plugin MainWindow start with some widgets not drawn?

I have a QGIS plugin written in Python which uses a MainWindow to hold a few other widgets. When the window first gets shown, some widgets are drawn and some are not. When I resize or minimise/restore ...
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2k views

QGIS 2.0 Plug Repository Connection Failed

I'm trying to connect to the QGIS Official Plugin Repository but the status within the Plugin Manager window is always"unavailable" for the URL - http://plugins.qgis.org/plugins/plugins.xml. I'm ...
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356 views

QGIS 2.0.1-3 not opening

I've excitedly just downloaded the latest version of QGIS 2.0.1-3 (QGIS Dufour) and now it won't open. I performed the exact same process last night (without problem) on my home laptop (64-bit OS &...
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525 views

Unable to render layers in MapCanvas using PyQGIS/PyQt4

I am trying to get some layers into a MapCanvas and style them. I am following the PyQgis Cookbook info here but my code is just not working. I've been spinning my wheels on this for over a week now ...
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602 views

Using Select Expression and Field Calculator in ONE STEP with QGIS

I have an Open Street Map Shapefile and i want to use Field Calculator to add information to a field called a800900 according to the field TYPE of street, by different area (field called ID_2). The ...
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170 views

QGIS, SpatiaLite and GPS integration

I have QGIS an, access database and a Haicom gps all connected and running on a windows 8 machine. I want to integrate all 3 items so that while in the field i can enter information into the ...
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570 views

Maxent out of bound error?

I selected my climate data from wordclim ( tile 29 ) and then used QGis to convert the data to .asc format . My occurrence data is in degree decimal.But when I run Maxent on any layer it says that the ...
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105 views

Merge (a lot of) features using QGIS or other open source

I have one shape-file with a lot of features (polygons) and if I try to merge these into one big polygon in QGIS it takes days to complete the merge. So I wonder if there is another way? I saw this ...