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

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1answer
62 views

Plotting two Maps on one sheet in QGIS?

I am trying to put two different maps on one sheet, one of them should show the raster image of a survey, the other one the vector-rendering of anomalies of the same area, but without the raster ...
2
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0answers
57 views

Performance difference between focal statistics (ArcGIS) and neighbor (GRAS or QGIS)

I tested minimum, maximum, and average neighbor (circle radius = 161 pixel) using ArcGIS, GRASS and QGIS: ArcGIS (10.1): it takes only one minute GRASS (6.4.3): it takes 123 minutes for every output ...
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1answer
52 views

Georeferencing Old Mining Maps (Floetzkarte des Oberschlesische) in QGIS?

I am trying to georeference some old mining maps (Floetzkarte des Oberschlesische) in QGIS 2.9. I have already tried to do that by marking known points on present satelite photos, but the results were ...
2
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0answers
26 views

QGIS atlas generation - batch process for many atlases

I have many different QGIS projects, each one is designed to create one particular atlas or map book in pdf format (one different book per every QGIS project). Month by month I must actualize each ...
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0answers
24 views

Why would Nearest Neighbor Analysis give 0 observed mean distance?

I am working with small datasets (around 100 points or less) with Nearest Neighbor Analysis in QGIS 2.8 (although I also tested in 2.6 and the result is the same). I have the layers referenced with a ...
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0answers
50 views

Add Surface Information alternatives in QGIS?

Is anyone aware of a single tool or possible routine of tools in QGIS (2.6) which emulate the results of the ESRI 3D Analyst tool 'Add Surface Information'? I have several polygon shapefiles (some ...
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1answer
41 views

QGIS - Geocoding addresses to coordinates

I've got an Excel file which includes known locations with their exact address (street, house number, city, state). This Excel file does not have a geographical column. Also, I have a .shp file inside ...
5
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2answers
72 views

Is it possible to have the attributes fields already filled from the previous object?

I need to create a lot of points with lots of attributes, but most of the fields are the same, so I don't want to edit all the fields all the time. Is there a "remember previous fields" function ...
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0answers
25 views

How to convert points distribution toward surface information?

I'm working with QGIS 2.6 I have a points layer representing different bus and train stops. I applied a categorized symbology; each colour represents a class of value (field regarding time access ...
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0answers
33 views

How to change symbol size in QGIS map composer legend?

I need to set an identical size to several symbols inside a QGIS map composer legend. The 'Symbol' menu in the Legend properties allows to set a height and width but this has no effect on the size of ...
2
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1answer
27 views

Generate a raster with a uniform value using QGis

I'm working on a project using the qgis-modeler and i want generate a raster with a uniform value. i'm using r.surf.random function of GRASS which need min and max value but i want have only one ...
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1answer
24 views

I want to compare multiple raster layers against each other to identify changes in pixel values over time

I am using LAI values to assess vegetation growth over large areas. I want to be able to identify areas that are doing well and areas that are decreasing based on the changes in pixel values. Ideally ...
4
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0answers
62 views

QGIS and the South Pole: bug or feature?

I am trying to work with some data from Antarctica in QGIS. I have defined this new projection: +proj=laea +lat_0=-90 +lon_0=0 +datum=WGS84 +units=m +no_defs And started adding a few vector layers. ...
0
votes
1answer
22 views

Radiometric Indices error

I have successfully included otbApplicaton in my python code. Tested the otb inclusion it is working fine. I am using the following code to generate NDVI output from the landsat image. from sys ...
1
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1answer
113 views

qgis refresh button for attributeactions

QgsVectorLayer* vLyr=static_cast<QgsVectorLayer*>(aktLayer->qgsLayer); vLyr->actions()->addAction(QgsAction::ActionType::OpenUrl, "Link im Webbrowser öffnen", "[% "+sAttribute+" %]" , ...
2
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1answer
32 views

How to update a column in a layer with NULL currently to nearby value in QGIS?

Currently I have a layer with construction year attributes in it. Not all of these are filled out and I figure it is reasonable to update them with the construction year of the nearby elements as they ...
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0answers
18 views

How can I create a warp mesh to match two close but not identical datasets together?

I have two datasets for Mars. One of them is the Mars Viking color mosaic, the other the Mars Global Surveyor black and white imagery. When I overlay the two datasets, it becomes obvious that the ...
3
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1answer
57 views

Misalignment of EPSG:4326 and EPSG:3399 coordinates

I'm having a QGIS project in local coordinates (Gauss-Kruger, EPSG:3399) with some layers in the same reference system. On top of that, I want to display point coordinates, which I digitized using ...
0
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1answer
26 views

Problem calling qgis2leaf outside the QGIS

I am a computer programmer starting with PyqGis-Python, and I’d need to automatize the creation of a webmap using the plugin of qgis2leaf from a QGIS Project. I have reached to call “import ...
3
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3answers
97 views

Is it possible to perform automatic snapping of polygons in QGIS or ArcGIS?

Note: in the picture below white space between the polygons is blank space – it does not contain any polygons as a result of Intersect or Union functions.
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0answers
26 views

qgis Points data from KML file

Forgive me if this question has been asked before. My search of the site did not turn up anything relevant, so I decided to ask this question. I have a KML file with Waypoints and several Tracks in ...
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0answers
18 views

Multi Label with Multi Placement

is there any way to add multiple label at different placement in qgis. Suppose I have a vector layer for line geometry and my attribute are name and route number. Now i want to add the route number to ...
2
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2answers
108 views

How to use `layer.getFeatures()` in a standalone script?

I am following the QGIS Cookbook and this post where it concerns reading attributes from layers. I would like to exploit this method and implement it into a standalone script. Essentially, I want to ...
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0answers
17 views

Error in projection Qgis [duplicate]

qGIS- when I try to project using +proj=robin +lon_0=-150 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs In order to centre on the Pacific I get this: Any advice? Thank you!
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0answers
47 views

How can I export symbology and labels with QGIS Leaflet to webmap?

If I make a map in QGIS export it with Leaflet the symbology and labels don't appear on the webmap. Is it possible to export them? If yes, how to export the all map?
2
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1answer
43 views

use gdal python bindings from the QGIS folder in a custom script

I have QGIS installed (on Windows) and can import this line from the QGIS Python console: from osgeo import gdal When I try the import in a python file it doesn't work Traceback (most recent call ...
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1answer
43 views

Resolution problem

I have a Landsat TM image and in QGIS I used Clipper to crop my image. Then, I tried to reprojected it via Warp (Reproject) and the pixel size goes 29.9936,-29.9936. I do not understand why this ...
2
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2answers
40 views

Change line into multiple segments where they overlap with nodes and vertex (qgis)

I have one (very) long line (e.g. line 2) I also have another line (line 3) which nodes are snapped with two vertexes of line 2. I want to break line 2 up in three segments. Is this possible by using ...
2
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0answers
22 views

Error while loading shared libraries libqgis_core.2.9.0

I have complied QGIS version 2.8.1 from source, according to the instructions from https://github.com/qgis/QGIS/blob/master/INSTALL Now after successfully running ccmake .., make and make install ...
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2answers
53 views

Fractional Area Calculation

I have a file (in both raster and vector) of different districts in a country. I have also made a grid of 1 deg * 1 deg (both vector and raster) of the country. I want to calculate the area of each ...
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0answers
19 views

Grouping layers in QGIS? [duplicate]

I'm trying to group a large amount of layers together. They are a mix of Polygons and Points, I would like to create individual groups by the layer's name. Anyone have any ideas?
3
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2answers
77 views

Can't export customer's shapefile to latitude and longitude

I'm very new to this application so bear with me. I hope that I am missing something very elementary. I have a shapefile supplied by my customer. I need to get the latitude and longitude for each ...
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0answers
32 views

Gradient fill based on scores (similar to elevation)

I'm rather new to using GIS (QGIS, specifically). I've mapped out a cohort of around 550 patients across Long Island, New York based on their full address by using MMQGIS plugin. This data is ...
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0answers
27 views

Creating slippy map from large shapefiles?

I am trying to create a map of the UK based on a number of open data sources (Ordnance Survey Open Data, OSM, some CSV files etc). My end goal is to create a map of the whole of the UK that I can ...
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0answers
42 views

Making QGIS custom form modal?

I have created a custom form for entering attribute values for newly added features / editing attribute values for existing features of a shape file. I chose the ui file as "Edit UI" and a python file ...
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0answers
17 views

How to use cx_Oracle db connection with OGR API

I am creating ogr datasource for oracle spatial using OCI connection in pyton code successfully. I can also get the layer from the datasource and I can add new features. But I am also using ...
4
votes
2answers
111 views

How to digitize building footprints with orthogonal edges?

Using QGIS, I am trying to digitize an old raster map, and because I ultimately want to load these 2d layers into sketch-up to turn into 3D models, I need everything to be square. Here's a sample of ...
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0answers
90 views

ECW support for QGIS 2.8 (Wien) and Ubuntu 14.10 (Utopic Unicorn)

Getting QGIS 2.8 (Ubuntu 14.10) ready for ECW files is really a pain. I've no terminal experience and it took me several hours to install the ECW JPEG 2000 SDK 3.3. What I did so far: #download ECW ...
3
votes
2answers
119 views

How to add a legend to a canvas in a standalone PyQGIS application?

I am trying to develop a standalone PyQGIS application. The map display does not pose any problems, but I do not know how to add a legend to the canvas.
3
votes
3answers
122 views

Which UTM zone to use for a large country?

I want to reproject OpenStreetMap roads data from the current projection (WGS 84) to UTM, since I read in another GIS.SE discussion (How to get $length in meters in QGIS?) that WGS 84 cannot be used ...
0
votes
1answer
55 views

Converting .ecw to .jp2

Is there any easy to use software for converting .ecw/.eww files to .jp2/.jpw files without loosing the georeferencing? I don't want to use proprietary file formats with QGIS. EDIT: I've deleted the ...
1
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1answer
48 views

How can I get features that satisfy a QgsExpression using PyQGIS?

I have two fields say "State" and "name" which would be get from the two comboboxes. After which, based on the current text in the combo box, I want to make QgsExpression and feature that satisfies ...
0
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1answer
43 views

How to access shapefile m-values with pyqgis?

Does anyone know how to access (read/write) m-values of a line-shapefile using pyqgis? I know how to do it with arcpy cursors ...
0
votes
1answer
16 views

How to convert a specific multipolygon to minimum polygons

I've got this kml file with one multipolygon inside. A link for the file are here multipolygon.zip My goal is to get a multipolygon with the minimum count of polygons with only outer border and ...
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0answers
55 views

Problems installing QGIS 2.8 Wien on Windows 7

Having trouble upgrading from QGIS 1.8, which ran just fine, to QGIS 2.8. I'm running 64-bit Windows 7. After uninstalling QGIS 1.8, I've been trying for several days to install the 32-bit version of ...
1
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2answers
109 views

Having trouble matching up U.S. Census shapefiles in QGIS

I'm trying to use the U.S. Census shapefiles to figure out what census blocks make up which state legislative districts. I decided to test the method on a state where I already had this data to see if ...
0
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0answers
28 views

Is PyQt4 'drag and drop' functionality available in Qgis Plugins?

In Qgis 2.8, is it possible to use the PyQt4 drag and drop classes (dragEnterEvent, dropEvent) to interact with items from a qtreeview, in a Python Plugin? Is it possible to hook into the ...
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1answer
66 views

QGIS custom Form - How to bind a value from a QComboBox?

I am trying to build a custom form for field data collection (bird species) with some python logic. The python code inserts values into a QComboBox: At the beginning of the list it adds the twenty ...
1
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1answer
36 views

How to implement Add feature action from PyQGIS

I'm trying to implement / reuse Add Feature functionality in my python plugin. there a class/function that handles geometry creation on canvas based on layer geometry definition? I'm checking API but ...
2
votes
2answers
49 views

Placement for Label

Is there I can define expression for the placement of label in vector layer like when the scale is less than x label placement should be curved else it should be horizontal. I am using Pal setting. I ...