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

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155 views

How to improve creating contours for super-high unnatural mountains?

in a current project I am working on we are not mapping the actual height of a landscape rather mapping the interest which specific stakeholders have in parts of the region. So, what we did was the ...
3
votes
1answer
361 views

How do you export to georeferenced PDF from QGIS 2.0?

When I use the print composer in QGIS, there is no option to export to georeferenced PDF using GDAL. Do I need to export from somewhere else or how do I go about exporting to georeferenced PDF? I am ...
5
votes
3answers
4k views

3D visualisation with open source GIS software [closed]

I'm searching for QGIS (or other open source GIS software) tools that can analyse XYZ data. Also I'm interested to hear about if anyone have migrated to non commercial software regarding geological ...
0
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0answers
35 views

qgis python plugin enabling other plugins

maybe it is a stupid question but i am new in qgis. I developed some python plugins and they work correctly, now what i would like to do is to install a "door" plugin that after asked ...
5
votes
1answer
3k views

QGIS and SQL Server Spatial Tables Performance

I'm trying to get a SQL Server 2008 R2 spatial database up and running to streamline the production of maps using QGIS. Currently I just have a handful of spatial tables (a postcode level point table ...
4
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0answers
205 views

QGIS: How to reverse vertex ordering in polygons

I am working with an Oracle spatial connection in QGIS through which I am accessing and editing a vector layer. I find that when I edit a geometry, the vertex ordering is reversed (to clockwise in the ...
4
votes
1answer
262 views

How to find a single point furthest from any road?

I have a road layer of a country. What method or plugin would you suggest, to find a single point furthest from any road (but as you can see, there is a coastline, so points in the sea can't count) ...
1
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1answer
366 views

How to add the current document path on Print Composer?

I'm trying to demonstrate to my company that we can begin using QGIS in conjunction with (and sometimes even instead of) ArcGIS and MapInfo. I've started setting up some layout templates but have run ...
2
votes
1answer
224 views

How to synchronize the marker's rotation field with the angular distortion in the map projection

I'm Using QGIS 1.8.0 to plot a global dataset showing the positions of aircraft in flight. The data I have are .csv files with three columns: Latitude, Longitude, and angle of travel. I assign ...
0
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2answers
52 views

Change precision of Real column

I have a sqllite table which has columns to hold the hectares and acres of polygons but I only want to have two digits after the decimal point - when calculated they have 14! How do I change this so ...
2
votes
1answer
402 views

Thematic map with points QGIS

I would like know how can I make a thematic map (soybean production) with density points. In this case the points are randomly plotted in a municipality area. Please, see an example in the image:
0
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1answer
1k views

How to resolve Geoserver ERROR: Operation on two geometries with different SRIDs

I am working on Geoserver Version 2.4.2 . I have one layer 'beat' in postgresql database. I have publish layer in geoserver but its not opening OpenLayers layer preview link. It gives error as ...
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0answers
55 views

Why legendLayerActions is not available in QgsLegendInterface

There's a reason why QgsLegendInterface (the python interface to QgsLegend) doesn't expose: QList< LegendLayerAction > QgsLegend::legendLayerActions( QgsMapLayer::LayerType type ) const method? ...
1
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2answers
911 views

How to clip an Openlayers OSM Background to a Vector Boundary?

I'm new to QGIS. In my project i have two layers: one is my vector (city boundaries) and the other is the OSM (obtained with the plugin). How can I cut the OSM along the edges of the vector? I want to ...
1
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1answer
618 views

QGIS hillshade error “GDAL provider: Cannot open GDAL dataset ”

I am using a DEM and using menu Raster > Terrain analysis > Hillshade. When I type a simple output file name "MyHillshade" and then click "OK", I get a two-part error message that says: "GDAL ...
1
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1answer
123 views

Which File to load from National Hydrography Dataset?

Start-over beginner here. I'm using QGIS 2.0 on MacBook with OS X 10.8.5. I downloaded a National Hydrography Database file. Unzipped, it is titled NHD11032_NM.gdb. I try to add the layer as a vector ...
1
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0answers
127 views

How to run PostgreSQL stored procedures from QGIS? [closed]

I'm trying to figure out if it's possible to run a stored procedure in a Postgres database from QGIS, more specifically I would like to do this from within a python plugin. In this case I'm trying to ...
1
vote
2answers
864 views

How can I create a merged buffer in QGIS then count points that fall within it

I have a QGIS plan which shows ponds (as points in a shape file with an OS tile as a background) within a survey area. I need to calculate the total number of ponds within 1 km of each of the on-site ...
2
votes
2answers
366 views

How to use ggplot with Processing in QGIS 2.0?

I'm trying to use R scripts within QGIS thanks to Processing. There are some example scripts available and I achieved to plots different columns of the attribute table (with the plot built-in ...
0
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0answers
115 views

Can I simplify polygons in QGIS by Size?

Just wondering if it's possible in QGIS to simplify polygons based on size? I've done it many times using the tolerance level to reduce the overall size however in this case each polygon cannot be ...
0
votes
1answer
88 views

Raster to Surface

I have a raster and I have been asked to modify some pixel values in it. Is there an open source way to do this? I would guess that I have to create a 3d surface, then manipulate the surface, then ...
3
votes
1answer
640 views

How to build a confusion matrix for image classification using SAGA or QGIS?

I did a supervised classification of a Landsat image subset using my training data polygons. I used SAGA GIS for that and everything worked out fine. Now I am stuck since I have no clue how to ...
2
votes
3answers
232 views

Generating a polygon tile index from multiple vector datasets

OK. well this is silly, in that there is no way it should be as difficult as it has been for me to find information regarding how to generate a polygon tile index from multiple vector (contour) tiles. ...
0
votes
1answer
60 views

How can i create single feature fwith Combining Selected feature qgis?

I am trying to create a single Qgsfeature from the Combination of selected features in Pyqgis. Currently i create the feature using a loop over selected features and combine them 1 by 1. but this ...
0
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2answers
397 views

Is it possible to set a reference scale in QGIS?

It's a little tricky to pick label and feature styles (line thickness, colours, etc) in the map canvas because they don't reflect what I would see in my print composer which is at a different scale ...
2
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0answers
733 views

Kriging with SAGA and QGIS [duplicate]

I have the "processing" toolbox installed on QGIS2 and it would appear to give me access to the SAGA variogram tools and and kriging tools. What I am missing and what I can't find via Google either, ...
0
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0answers
445 views

RasterXSize from gdal Nonetype error

I have this code to create a raster file in python: fileInf = QFileInfo(userIntervals) baseNam = fileInf.baseName() rlay = QgsRasterLayer(userIntervals, baseNam) gdalRast = ...
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0answers
307 views

How Can i create a Vector layer from selected features qgis

In my qgis plugin i select dynamically features from a Vector layer. and currently i create a new layer from selection on combining all feature into a new feature: theField = QgsField self.theString ...
5
votes
0answers
107 views

Distribute QGis plugin which depends on certain Python packages

I developed a plugin for Qgis which depends on some Python packages. On Linux and Mac, this is not really a problem because I can easily install them with the system pip command. Windows is another ...
1
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2answers
260 views

Saving a gml layer does not change coordinates

I am trying to export a gml layer to geojson with lat/lng as the preferred coordinate system. So what I did was a 'save as' on the layer with selected CRS: 'IGNF: WGS84G'. Now I was hoping it ...
3
votes
3answers
231 views

Can Mapnik 2.2 and Qgis 2.0.1 be installed together?

I'm using LM15 (== Ubuntu 13.04 Raring) with the Launchpad repos for Qgis Unstable 2.0.1 and Mapnik 2.2.0. Quantum wants libgdal1h; Mapnik wants libgdal1. As soon as I install one, the other gets ...
2
votes
1answer
142 views

How to control road labels in Atlas QGIS 2.0?

I'm producing map books for our water assets. These books are taken out into the field by the workers so they can see where various 'things' are for the work they need to undertake. There are over 200 ...
2
votes
2answers
969 views

Calculate area covered by a particular raster layer within polygons in QGIS

I am trying to extract information on vegetation cover within a set radius of point locations (my sites). I have succeeded in creating a new vector layer of circles with a 5 km radius around my sites. ...
1
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2answers
108 views

How to convert small overlaping polygon features to inner ring in QGIS

I have a polygon vector layer with overlapping features (like below) and I would like to convert the features that are fully contained inside the bigger polygons (ie feature 2 and 4 below) into inner ...
3
votes
1answer
566 views

Upgrade QGIS from 1.8 Lisboa to 2.0?

I have QGIS 1.8 and I want to upgrade to 2.0 Dufour... Should I just download the file and launch the installation? Or first uninstall 1.8? Thank you! Lily
0
votes
1answer
170 views

How to create shapefiles with z coordinate with QGIS

I'm working with QGIS, and I want to create a shapefile with the elevation coordinate, I can't find something similar to what I was used to do in Arcgis, can you help me? Thanks for your help Luís
5
votes
1answer
909 views

Adding Multiple Maps in QGIS Composer?

I am working with QGIS Composer 2.0 and I would like to add a second map. What I would like to do is to have a main map that takes up the majority of the print area. This map, Main Map, will have ...
0
votes
0answers
198 views

how do I add attribute features to an attribute table which already exists?

Using Verson 2.0, downloaded as normal. I have an ESRI shapefile of my road map for 2006. I have a paper map of roads for 1969. I want to see what roads have been built between 1969 and 2006 (none ...
1
vote
1answer
589 views

Arc ASCII Grid output problem in QGIS 2.0

I used to convert tif files to ascii in Qgis 1.8 using gdal translate without having any problems with the output i.e. I have the normal heading and values. When I upgraded to 2.0 I started to get the ...
0
votes
2answers
483 views

Developing standalone gis applications using pyqgis

I am trying to develop a standalone application using pyqgis but I have no clue on where to start and where to write the code to make it happen so if anyone can provide me a tutorial to getting ...
0
votes
2answers
265 views

Problems with Polygon Reshape Feature [closed]

I've created a polygon and closed my project, after opening the project again, i can't use the Reshape Feature tool in that specific polygon. But if I create a new polygon in the same shapefile I can ...
1
vote
2answers
418 views

On the fly transformation From WGS84 to NAD27 with proj4 code

I want to use this proj4 code: +proj=utm +zone=19 +ellps=WGS84 +toclrk66=-3,142,183,0,0,0,0 +units=m +no_defs or this one +proj=utm +zone=19 +ellps=WGS84 +tonad27=-3,142,183,0,0,0,0 +units=m +no_defs ...
2
votes
3answers
963 views

How to remove vertices or lines within a polygon?

I have transformed a *.dxf-file into a polygon shape-file. In many of the polygons i have lines whicht do not belong there but i can not delete them as i normally delete vertices on polygons by ...
3
votes
0answers
116 views

Creating a new raster based on pixel value of original raster using raster calculator but new layer is not evident [closed]

I am trying to create a new raster based on a current raster (w001001 - NVIS) which has one paletted band, with palette values ranging from 1 to 29, with each palette/value representing a vegetation ...
1
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2answers
539 views

TIFF/Raster to Point shapefile question

Apologies in advance if this question is incredibly basic, but I've been googling around and I just don't know where to start. I've downloaded some nighttime luminosity data from NASA, and the data ...
1
vote
3answers
205 views

trouble installing the qgis2kml plugin (or, how to install plugins not available in the Plugin Manager from source)

I'm trying to install the qgis2kml plugin for qgis. Its not showing up in the Plugin Manager search and the only qgis "repositories" I can find are websites for downloading source code. Which is ...
3
votes
1answer
142 views

Tornado Data Points: Linking 2 Points in QGIS on the Same Row

So I've got these tornado .csv files that have two latitude & longitude entries with the left-most in the table being the beginning point and the right-most being the ending point of the tornado, ...
0
votes
1answer
95 views

How can i stop rendering Qgis

In my python plugin ,i select features from a vector layer dynamically using a loop and executing : VectorLayer.select(feature.id()) when i start the loop, the selection become very slow because ...
4
votes
1answer
276 views

Debugging errors of SAGA interpolation algorithms in QGIS 2.0 Processing

I encounter recurrent problems with the geoalgorithms that perform interpolations. No matter technique I use I end with the following errors. As state in OGR tab QGIS is unable to open a file in C ...
2
votes
2answers
65 views

Join by location on Qgis when target layer has multiple layer

I posted here a while ago about spatial joins. I have a huge dataset (20,000?) of bird and mammal ranges. I have another dataset of all the countries. In qgis, I was attempting to link the two ...