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

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1answer
104 views

Error importing raster into GRASS plugin in QGIS

I am trying to import a tiff raster file into GRASS however every time I do this the below error message comes up. I am using a custom CRS so I have tried changing it back to the default CRS but still ...
2
votes
2answers
94 views

Distance from centre point to other points using QGIS?

I have a question of something I actually thought was pretty simple...I have a few points around a centre point. Now I want to know the distance from each point to the centre point. Is it possible to ...
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1answer
67 views

Setting resolution for GRASS raster

I am trying to calculate volume using the GRASSplugin. I have my area information in vector format and my depth information in raster. I read that it is important to set the raster resolution before ...
2
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3answers
212 views

Saving project from QGIS to CD so it can be used on other computers?

For purpose of a project, I created a project in QGIS - aerophoto base and 3 layers. It works perfect on my computer, but if I save it on CD, the project doesent work on any other computer... I saved ...
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3answers
105 views

How to divide attribute table in map composer between 2 or more pages?

Does anyone know how to divide attribute table between 2 or more pages? In exported PDF it's unfortunately clipped.
3
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1answer
84 views

How to change the color of vector layer of QGIS in api?

I'm using QGIS-2.4.0 api to develop app in C++. When I add a vector layer to the app, the vector map's color would be random. I used QgsFeatureRendererV2 to get the geometry type of the layer, my ...
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1answer
131 views

QGIS Web Client zoom and scale

I have a problem with setting up zoom levels and max/min scale in QGIS web client. It looks like that values used in GlobalOptions.js file does not apply. Right now ZOOM_LEVELS is 70, maxScale 50 and ...
3
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1answer
161 views

QGIS 2.4.0: dissolve tool renders artifacts / errors

The dissolve tool (vector>geoprocessing tools>dissolve) renders some artifacts on shapes with high number of polygons. I’m using a shapefile with 3222 polygons and I’m trying to dissolve it using the ...
2
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2answers
719 views

How to display distance in meters (km) and not in Decimal Degrees in QGIS 2.4?

I am a GIS beginner, and I have a question about how to get the distance between two points in meters instead of decimal degree. In QGIS 2.4 I have a project with two point layers (in WGS84). From ...
2
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1answer
50 views

QGIS vector layers do not match DEM?

I have a DEM (saved as a .tif) and, using QGIS, I want to clip the DEM using a vector mask. The function will not work. Am I missing critical step?
2
votes
2answers
101 views

Can GDAL fill elevation below a certain value?

I have several GeoTIFFs that I'm working with to create contours using gdal_contour. One of them crashes the utility. gdalinfo tells me that the computed min values for band 1 and 2 are ...
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1answer
325 views

Creating a World Population Density Map

I am trying to make a world population density Choropleth map (country level). The data I am using is publicly available on World Development Indicators website. Pretty much, I have an excel file ...
5
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1answer
206 views

Is there touch screen support in QGIS for Windows?

I have a new 2in1 PC (laptop and tablet). It would be very nice to navigate in QGIS using its touch screen I.e. zoom in and zoom out using double finger touch, like on a mobile phone, etc. Maybe ...
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4answers
174 views

QGIS Plugin with save settings dialog

I am writing on an update of the qgis2leaf plugin. It would be great to store the settings of the plugin UI (like which checkboxes are checked, which strings are used) in a separate file (like xml or ...
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0answers
120 views

Vector points from csv file wrong location in QGIS

I am using QGIS 1.8 (I know old version), and uploaded a csv file with coordinates. The underlying basemap is from Google, using the Open layers plugin. This basemap uses WGS84-epsg3857, and my vector ...
2
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2answers
243 views

QGIS installation from OSGeoW4: entry point not found in qgis_core.dll

I have installed QGIS through OSGeo4W installation. My operation system is windows 7 64x. I try to start the program QGIS Desktop from start menu this error: Do I need to do something? Installation ...
0
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1answer
74 views

QGIS 2.4 mapRenderer.extent() does not equal mapRenderer.setExtent()

Could anyone help explain this QGIS 2.4 python console code? I would expect the return value of .extent() to be the same as the bounding box given to .setExtent(): mapRenderer = ...
2
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2answers
1k views

Saving selection as new shapefile using QGIS gives OGR error?

I have an issue saving a set of polygons as a new layer that I've selected using the polygon select tool in QGIS. After selecting the polygons in the main (source) layer, I've tried two ways: I ...
5
votes
2answers
218 views

What's the most efficient way to load feature attributes into a numpy array?

I am currently working on an add-on that relies on the user choosing fields of tables (that can be from shapefiles, csv or dbf) that are open in QGIS and then making computations with such data. ...
2
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1answer
262 views

Combine two grids with a small area of overlapping pixels to a new raster in QGIS/SAGA

The first grid is 1 byte and the second is 2 byte. The new raster should have a blended transition. How can i do this?
1
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1answer
83 views

How to simplify a multiline geometry in QGIS?

I'm trying to simplify my shapefile, which uses a lot of vertices to represent curvatures, by using the Generalizer plugin. But no matter what threshold I use for Douglas algorithm, it still includes ...
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0answers
53 views

How can one use Google Maps API to mimic QGIS projection/CRS

I used QGIS to find the extents of a list of features. However, the resulting data auto-generates the CRS and changes it from WSG84 to a custom one. Is there a way to use the autogenerated CRS in ...
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3answers
115 views

Why do I get an error message at QGIS training manual 3.3?

I have a problem following the QGIS training manual lesson 3.3 (Ratio Classification). You have to add a column to an SQlite layer. The new column is AREA. I followed the instructions and added it as ...
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1answer
122 views

Difference between source SRS and target SRS in Raster Warp function

Hello I am trying to change a raster layer projections from WGS84 to a custom Lambert layer using 'Raster' --> 'Projections' --> 'Warp' function. I have been asked for source SRS and get SRS. what is ...
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1answer
324 views

Extracting raster values with polylines in QGIS

I have a polyline shapefile that represent a road an a raster grid with slope values. Is it possible to interpolate the shape file and the grid to have the average slope of the road? I know that I can ...
0
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1answer
132 views

CRS of QGIS bounding boxes

I used QGIS to find the extents/bounding boxes of a list of features from census data. I used the following method: Vector - Research tools - Polygon From Layer Extent, which creates a new shapefile ...
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1answer
70 views

cannot split a line using QgsGeometry.splitGeometry in QGIS

I create a new qgis file and run the following code. # create a line line = QgsFeature() line.setGeometry(QgsGeometry.fromPolyline([QgsPoint(50,50), QgsPoint(10,10)])) # create a layer layer = ...
0
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1answer
195 views

Determining unknown Coordinate System using QGIS?

I'm trying to figure out the coordinate system of some data I downloaded from a no-longer-maintained USDA website. The data's still accurate, it's just floating in space. I've tried several ...
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0answers
145 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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0answers
81 views

Resampling air temperature gridded data to sub-grid resolution

I'd like to obtain a 30-m resolution gridded dataset of air temperature from the ~1km gridded data of WorldClim, of Hijmans et al., 2005) for a mountainous region. The easiest procedure (I thought ...
2
votes
0answers
93 views

How can I store height info from GPS in QGIS?

I want to use QGIS as a tool for collecting GPS-Data in the field. One use case would be simple surevy tasks where I want to store the three dimensional position of points. QGIS is working fine on the ...
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1answer
100 views

How to manage two map items in a QGIS composition with python?

I need to manage two different map items in the same map composition, with a stand alone python script. Each composer map has been referenced like this: composerMap1 = ...
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0answers
110 views

Problem Installing QGIS to Samsung Galaxy Tab3

I try to install stable and nightly(18/09/2014 last nightly) versions of QGIS to Samsung Galaxy Tab3 (Android) but unfortunately I can't. When the installation is completed asked me to confirm the ...
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1answer
55 views

Help request fixing map errors in QGIS 2.4

Background: I am currently working on a project that requires me to translate shape files into geojson format and then upload them into MongoDB. There is a problem with MongoDB that prevents it from ...
1
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1answer
39 views

Why am I getting small float numbers when aggregating points containing large integer values in QGIS?

I have a layer of points containing the centroids of European NUTS regions at NUTS 3, with population data in the atttribute table. I want to aggregate this population data to NUTS level 1, which is ...
2
votes
2answers
159 views

Multiple font markers in shapefiles in QGIS?

I'm making a UK phase 1 vegetation survey map and require to show the dominant plant species in a given polygon. In phase 1 these are shown as 2- or 3-letter codes e g Ri, Cys. These codes need to ...
2
votes
1answer
110 views

How to get into the Python API of QGIS?

After a few hours I am about to give up on finding a kind of documentation for the QGIS Python API that actually works/gives the correct information. It is obvious that there is no actual code ...
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2answers
185 views

QGIS raster calculator using abs() function

Is it possible to use the Abs() function in the raster calculator in QGIS? I've tried it, but it didn't work.
1
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1answer
138 views

Cannot produce pie chart in QGIS 2.2

I have a shapefile to which I joined two tables from a MySql database. I used one column of the first table to color the polygons in my shapefile which works fine. Three columns out of the second ...
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1answer
237 views

How to convert float to raster in QGIS

I have downloaded bathymetric data into QGIS. In order to use it I need to conduct a float to raster conversion. I have not been able to find how to do this on any of the forums. I have unsuccessfully ...
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0answers
126 views

QGIS processing framework SAGA NaturalNeighbor in external Python Script - No Output

I want to build a little script, which generates a NaturalNeighbor grid based on a point Shapefile. The script runs within my PyDev environment without any error messages, but no outputfile is ...
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0answers
42 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 ...
2
votes
2answers
163 views

How to calculate area of shapefile with a merged layer

so i have 'save as''d the new project and layer with my new Custom CRS project string being '+proj=laea +lat_0=70 +lon_0=0 +x_0=0 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs'. ...
0
votes
0answers
34 views

QGIS 2.4 How do I find and change measurement units? [duplicate]

I want to create 1,000m buffer around an object, but when I enter 1,000 as the distance I get something that looks more like a 100,000m buffer. I can enter 0.01 to get what looks like a 1,000m ...
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0answers
65 views

Specifying which fields in SQL Server table are lat/longs using QGIS?

I have successfully connected my MSSQL DB to my project and I am trying to add a layer to represent the data in a table. I want to make a density map using the lat/longs that are stored in two fields ...
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0answers
30 views

Calculation size limit to creating distance matrix using QGIS?

I have a shapefile of postal code for a city (Montréal). I would like to calculate the distance between all postal code. I tried to run the distance matrix after converting all postal code to a ...
0
votes
1answer
63 views

Can't save map with different projection in QGIS

I'm using QGIS 2.4 and am opening a shapefile I downloaded (specifically from: http://www.naturalearthdata.com/http//www.naturalearthdata.com/download/110m/physical/ne_110m_coastline.zip). What I ...
7
votes
1answer
160 views

Adding Route Shapefile (PolylineM) to QGIS?

I'm new to QGIS (and to this amazing forum as well) and I already have an issue : I received a Route Layer in SHP format (PolylineM). I've easily loaded this file into QGIS but it doesn't seem to ...
2
votes
2answers
736 views

Exporting 16 bit single-band to 8 bit in SAGA/QGIS

Everytime with every function (e.g convert data storage type or gdal-translat -ot Byte) the output is a completely white map with a black border. only the "save as" export works, but the TIFF also ...
2
votes
2answers
251 views

Any idea how to export multiple KML files from one SHP layer?

When exporting one KML, it's exceeding the Google Fusion Table's max limit of 100mb per upload. Fusion Tables however lets users merge more than one KML for a merged max size of 250mb. Any idea how to ...