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

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6 views

What is “Simplify tolerance” in QGIS's Simplify geometries tool?

I am trying to use QGIS 2.8 to simplify vector geometries. But I do not understand the significance of the Simplify tolerance value in the Simplify geometries tool. The documentation does not ...
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1answer
10 views

How do I add packages to Standalone Qgis's Python?

I have installed the QGIS 2.8 on my Windows 8.1 system, using the Standalone Installer. I now wish to install the VectorBender plugin. The docs for this plugin say, that I need to install matplotlib ...
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12 views

Different colors of rasters after loading back to QGIS

I am experiencing this issue longer time but sometimes it is really annoying so I would like to solve it. When I save an image from QGIS - no matter when using Project/Save as image or using Export ...
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2answers
26 views

How to map a building to only one grid which contain more than half of its area using qgis?

I have a shapefile of a city map and I have created vector grid as polygons. After intersecting the two shapefiles, a building will map to all the grids it overlaps. However, if I just want it to ...
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0answers
17 views

Using Esri grid format (*.adf) for raster calculation in QGIS?

I got problem with the ADF raster file. In fact I have a land use map in ADF file and I am trying to perform some raster calculation(from raster calculator) but its not working.I have also changed ...
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0answers
31 views

How can I use boolean value in QGIS style rule?

I'm trying to make a style based on rules, and I want to use a boolean field I have created for that. But I do the following: "field" like 'TRUE' "field" like TRUE "field" like 1 "field" like '1' ...
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24 views

Collecting data [on hold]

I'm using qgis, i'd like to know if there's an app that i can install on a tablet for collecting data, and after by connecting the tablet on my computer in order to upload the data ?
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0answers
17 views

Aggregating raster pixels in coarser resolution

I am trying to aggregate 3 meters resolution land use map to coarser 30 meter resolution in QGIS or ArcMap.In fact I wanna make similar with Landsat MSS and TIR resolution.Could anyone please help me? ...
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1answer
18 views

How to find the path after “cannot find module” message when I try to use grass tools in qgis [on hold]

I use mac and when I try to use grass modules in qgis (brighton) I get a "cannot find module" message.
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2answers
32 views

Running the ogr2ogr utilities in a batch file. Problems with command project

I have made a batch file containing a list of two commands. The first (-clipsrc) works properly, but the second not (-s_srs EPSG:4326 -t_srs EPSG:3857). Could anyone tell me where is the fail?. This ...
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24 views

I am building QGIS 2.6.1 from source code on windows 7, 32 bit and after successfully building all projects I get this error

Couldn't load PyQGIS. Python support will be disabled. Traceback (most recent call last): File "", line 1, in ImportError: No module named qgis.core Python version: 2.7.4 (default, Apr ...
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0answers
8 views

AddFeatures returned values …?

i try to add Features in a polygon vector layer. i'm using for example the following lines : fet.setGeometry(ft_com.geometry()) bool=pro.addFeatures([fet]) bool returns me True (i see the added ...
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0answers
16 views

Automated Viewshed in QGIS

I want to create a workflow with a QGIS script where I need a viewshed tool. There is a really cool viewshed plugin. Unfortunately I am not able to access it in the QGIS console. I also found out that ...
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0answers
9 views

Static link to latest QGIS version

I am trying to set up a local "mirror" of the latest version of QGIS using "Download station" in a Synology NAS. The intention is to provide the newest version of QGIS on a local network without ...
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0answers
24 views

Vector to Raster using GDAL (gdal.RasterizeLayer) : Error in Output Raster(generating output raster with NAN values)

For rasterizing a vector layer, I have tried gdal.RasterizeLayer method for converting vector(shapefile) to raster(tiff). But its giving raster output with NAN values(complete black image). I need ...
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0answers
19 views

Rectangular bounding box curved in D3.js

I am trying to project polygons to a map with a static background image using D3.js. The polygons looked slightly off in relation to the background so I drew the bounding box of the image, and sure ...
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0answers
32 views

Print an Automated Selection of Point Features

I have a point layer with around 1.3 million features where one of the columns in the attributes table contains dates in the format YYYY-MM-DD. Starting from an arbitrary date, say 2001-01-01, I ...
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1answer
41 views

How to publish a single (standardized) QGIS symbology which relates to different datasets of same schema?

Given a specific (locally extended/stored) symbology and styling in QGIS which refers to several different shapefiles or tables (GeoPackage/Spatialite), how can I easily move or share this with ...
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2answers
25 views

How to deactivate the Color Ramp in QGIS graduated vector styling?

I want to display points with different size and I DO NOT want to have a color ramp. Do you know how I can do that?
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0answers
21 views

How not to enforce lowercase field names in Spatialite?

I use a geojson file to publish a webmap. When I need to update the data I convert it to Spatialite, add the data, then convert back to geojson. Recently in QGIS 2.8 I found that the column names ...
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0answers
17 views

Get table of adjacent polygons

I am using the cb_2013_us_zcta510_500k shapefile to push zipcode polygons. I have the shapefile, and a SQL Server table loaded where the polygon is loaded in the GEOG data type. What I need is to ...
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0answers
28 views

Activating GRASS GIS in QGIS

Apparently, my linux ubuntu setup of QGIS doesn't contain grass gis, although when I initially installed it last week I added grass gis to the command line. Anyway, I typed in once again and installed ...
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0answers
34 views

How to get a “clean” polygon after using dissolve in QGIS?

I'm trying to obtain the boundaries of shapefile, thus to clean the inside as a matter of speaking. While I had expected that dissolve while get me a proper polygon, unfortunately it still has some ...
0
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1answer
37 views

Georeferencing raster in QGIS

Georeferenced raster in the QGIS not filmed the final display by raster footprints. Everything is in EPSG 32633. Path in GdalToools: Red is original footprint for image. I need rotate image ...
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1answer
32 views

How to fix “Detected out of bounds geographic extent”

I hope someone can help me to solve this problem. i want to make a map with TileMill v.01, when i try to add layer using shapefile (i use QGIS to edit *.shp file) or postGIS i always get error ...
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0answers
16 views

Legend disappears in QGIS 2.8 composer

I would like to keep my legend on as I export a multipage map set to PDF, but the legend appears to lose any layer items and just keep the title ("Legend"), which is what appears in my PDF document. ...
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0answers
13 views

Is there an easier way to package all data in a map file in QGIS? [duplicate]

Similar to the way an InDesign file has the ability to package all of the linked images and embedded fonts into its own folder—or how ESRI does it, is there a way to gather up all of the data layers ...
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0answers
24 views

Digitising - Separate fill and line opacities (or remove fill)

I have a client who specialises in aerial photograph interpretation and is in the process of moving from AutoCAD to QGIS. They find the auto 'fill' when digitising polygons really disruptive and ...
1
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1answer
36 views

portions of edited shapefile will not draw

I edited a shapfile of approximately 1500+ pipe segments yesterday in QGIS. When opened today (first in ArcMAP by another user) only about 10% of the pipes were drawn. The same happened when the ...
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0answers
23 views

Calculating “sun time” on areas with high mountains? Topography available

I'm wondering how to proceed if you want to calculate how a location on land will get direct sunshine at a given time on a given date (compared being in the shadow of the mountains)? The area is very ...
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1answer
26 views

Geocoding - looking to identify county from list of zipcodes

Using QGIS, how do I find county of an associated zipcode? I have zipcode for each point, however, I do not have a street address. I am hoping to aggregate my data to the county level using the ...
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19 views

Is the QGIS connection with ArcGIS “mapserver” still working?

I would like to add the Ocean Basemap to QGIS. I also found the other posts and I followed this procedure: http://hub.qgis.org/wiki/quantum-gis/Arcgis_rest Hovewer when I put in the Python console ...
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0answers
21 views

World DEM vs ASTER Digital Elevation Models accuracy

I use DEM essentially to create surfaces on AutoCAD Civil 3D and then to create terrain profile views. I have been using mainly ASTER imagery from which I extract 2m contour lines in QGis and then ...
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0answers
14 views

pyqgis, features geometry type changes to unknown after copying to anoter layer

Im copying a subset of features from a shapefile based QgsVectorLayer (polyline type shapefile) to a memory based QgsVectorLayer('LineString', layername ,'memory'): ...
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1answer
26 views

Why doesn't QGIS 2.8.2 Road Graph accept my road network vector?

I'm using the Finnish official Department of Transport's "digiroad" road network vector file, which has all kinds of roads, cycle paths etc on it, but I can't use Road Graph on it. If I create a new ...
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1answer
24 views

How to write a vector layer as tab delimited txt file using PyQGIS?

I'm using the following QGIS 2.8 Python code to save results to a txt file QgsVectorFileWriter.writeAsVectorFormat(inputLayer, "D:/dstest/my_csv", "CP1250", None, "CSV",True) I would like to be ...
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2answers
46 views

How to close a polyline in QGIS while digitizing?

We need to work on a line layer where some features are closed and some are open. The closed features need to be closed perfectly, so that the first and the last point of the polyline perfectly match. ...
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0answers
18 views

Can I mimic the “open” action with python and manipulate the field content used for the action?

I am using QGIS actions (type: "open") to link ECM searches to objects on the map. The basic syntax is very simple: protocol://searchterm1=[%"field1"%]&searchterm2=[%"field2"%] However, some ...
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0answers
21 views

Quick way to select by attribute and zoom to selection in QGIS

I need to visually control hundreds of points in a layer on top of aerial photographs. Using the attribute table, selecting (with column filter expression) and zooming manually is cumbersome - so I ...
1
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1answer
25 views

Taking a long time to load tables from oracle to QGIS

My workplace has an oracle database with a very large number of spatial tables. Therefore, it takes a long time to load the oracle connection in QGIS. Does anyone know how this could be speed up?
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0answers
32 views

Create new attribute ranking polygons by size in QGIS

I'd like to create a new field in the attribute table which gives the rank of the polygon by size. For example, the polygon of the largest size would be rank 1 and the smallest rank N. I was hoping ...
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0answers
30 views

GeoJson and D3.js multipolygon

I have this geometric shape file, so no map of a city. I store the two Shapefiles in a GIS database as a geometric form. Now, I want to visualize the geojson data. I created the GeoJson data ...
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0answers
24 views

Are there limitations for QGIS Composer images larger than 32768 pixels?

We are outputting a map file with composer : size 45,312 pixels width and 4,352 pixels height in TIFF and PNG format. The map is calculated but in the file we have only 32,768 pixels width show, the ...
2
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1answer
37 views

Save a table in ascending order in QGIS [duplicate]

Is there a quick way to sort an attribute table in QGIS in ascending order permanently and save it? My third column is an integrer, of course if I clik on the header the table will be sorted in ...
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0answers
13 views

Creating Shape by Density Criteria using QGIS?

I have a map with points plotted. Is there a way that I can make a circle of a certain radius (let's assume 10 miles) if the density of points in any given 10 mile radius is over a certain number?
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21 views

Why does the “local maxima” module in SAGA GIS put so many “maxima” points on lakes and plains?

SAGA GIS puts too many maxima points on plains and lakes. Why does it happen? Is there a way to avoid this? It's not really a big problem (the value is correct) except for the size of the SHP files in ...
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0answers
42 views

How to create a Shapefile of a subset of input features in PyQGIS?

I'm having some trouble applying my Python skills to develop some scripts in PyQGIS. For me it's far simpler to write it in ArcPy, but then again I wouldn't get that much satisfaction after finishing ...
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0answers
22 views

Radius settings under IDW interpolation Qgis [on hold]

I have a point data set that I want to interpolate in Qgis. I use the Grid (interpolation) under: Raster- analysis- grid(interpolation) - IDW. There is several things to tweak the output with that I ...
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1answer
20 views

Is it possible to display irregular values in the scale bar in QGIS 2.8?

Is it possible to display irregular - increasing values in scale bar in print composer? For example: 5, 20, 100, 250.
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0answers
7 views

Range problem in QDoublespinbox for different projections of data in QtDesigner\python

I have two QDoubleSpinboxes that updates the value of latitude and longitude of a point respectively. The data is in the CRS "EPSG:32643 - WGS 84 / UTM zone 43N" I had also set range of the ...