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

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11 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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9 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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18 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
19 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
15 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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13 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
21 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
31 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 ...
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1answer
33 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
31 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
12 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
17 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 ...
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1answer
35 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
19 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
22 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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0answers
16 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
17 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
12 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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16 views

QGIS 2.8.2 Road Graph doesn't accept 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
22 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
41 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 ...
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1answer
24 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
31 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
27 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
23 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
35 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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19 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
41 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
21 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
19 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 ...
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0answers
32 views

Merge vector layers problem with german names (ä, ü, ö…)

When I'm trying to merge (saga merge layers tool) some shape files I get an error log 'ascii' codec can't decode byte 0xfc in position 91: ordinal not in range(128) See log for more details ...
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1answer
29 views

How to eliminate polygon overlap areas in QGIS?

Is there a way to remove polygon overlaps within the same layer using QGIS, preferably removing the overlap area of the biggest polygon (having the greatest surface)? All of my polygons are in the ...
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0answers
25 views

QGIS Raster Calculator giving a NaN output

This is my first time using QGIS and I am trying to use it to generate NDVI maps from data captured by my UAV. However when I apply the NDVI formula in the raster calculator using my NIRGB image the ...
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1answer
26 views

QGIS Python Scripting permission denied

I've just started a Python Scripting tutorial on QGIS. The problem arrives right at the end, when I have to use this script: output_file = open('c:/Users/Ujaval/Desktop/airports.txt', 'w') for f in ...
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0answers
16 views

Masking Labeles in the Compositor in QGIS 2.8.1

i am looking for a way to remove/mask out the Labels that are under a composer Element, wich i moved in front of my main map. Is there a way to do this? I tried the mask addon, but it only seems to ...
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0answers
21 views

Remove no-data values from a raster using raster calculator

Can someone please tell me what the formula is to remove no data values from a raster in QGIS? I have a large DEM .tif file and need to remove the no data values. Is it better to use SAGA to perform ...
0
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1answer
29 views

Function to merge geojson and csv data in R

I have been using merge() to merge my geojson file with csv data in R. My codes are as follows: map@data <- merge(map@data, csvdata, by.x="ID", by.y="ID") However, after exporting the geojson ...
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0answers
26 views

QGIS web mapping using WMS server? [on hold]

I want to publish my QGIS map. How to make it using WMS as server and PostgreSQL as my database?
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0answers
22 views

Is it possible to use GPS navigation with track up in QGIS 2.8

Can we have a rotating map while navigating with a GPS so our track is always pointing up? Just like a car GPS
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3answers
38 views

Create a reference number (id) based on x coordinate in QGIS

I would like to add a reference number to a point table. I would like this value to increase as I move from west to east across my data. So the values read 1 to n from west to east. I have an ...
1
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1answer
20 views

Receiving NULL values from Point Sampling Tool in QGIS

I am using QGIS 2.8.2. My project includes a raster layer of flow depth representing the output from a flood simulation (.DAT file). It also includes a vector layer of points representing the ...
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1answer
25 views

where to download gdal_polygonize.py?

I am trying to help out a friend of mine. She learnt GIS in school in the past using ArcGIS but has recently installed QGIS package on her Mac OSX. When she tries to render raster into shape file, ...
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1answer
20 views

Spatialite table column is function in itself

GOAL: I'm trying to filter all the 1's in a spatial boolean operation in Qspatialite, the spatialite plugin for QGIS. ATTEMPTED SOLUTION: My solution is to perform the boolean query first, export the ...
1
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1answer
75 views

Excel XLSX data with coordinates displayed as points

I am preparing a course for QGIS newbies, which includes handling Excel spreadsheet data in QGIS. It's so easy: Just drag an XLS, XSLX or CSV from Windows Explorer to QGIS! For data with no ...
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0answers
16 views

Grass functions (for example, r.li) on QGIS Processing Toolbox

I need to know if it is possible to add other functions, such as r.li to Processing Toolbox. Thanks.