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

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11 views

How to use SpatialOperator in filter expression in QGIS

In a python script I want to specify a request filter expression using a spatial operator. I am following the general syntax "field name" operator condition. For example: ...
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15 views

How can I check If Features do not have an SRID set or are similarly malformed? [duplicate]

QGIS does not display all Features of Layer and behaves weird instead I got the comment: "How did you create the other features in PostGIS (as opposed to the ones that were edited)? My initial ...
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1answer
31 views

Why is the heatmap color not showing in TileMill?

I created a heatmap on QGIS (2.8) and styled it using singleband pseudocolor. I want to turn it into map tiles, so I added the TIFF as a layer in TileMill. However, when it's in TileMill, it loses ...
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1answer
65 views

QGIS corrupting shapefiles?

I'm hoping someone out there might be able to help or suggest some tests to try and resolve some very odd QGIS behaviour of late... Our core GIS team of 4 users has been testing v2.10 prior to ...
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1answer
39 views

Autocad DXF to Qgis and exporting to KML for viewing in Google Maps

/ Background: I have a DWG trace made in AutoCad using Gauss-Kruger coordinate system ( a CRS used in Slovenia ). I'm using AutoDesk Map 3D to transform the coordinate system to WGS84.PseudoMercator ...
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0answers
43 views

Use cython in QGIS?

I've wondered for some time how to use Cython in QGIS. I know I can integrate a Cython code in python, but I want Cython to handle QGIS classes. QGIS is built upon QT, every qgis object is a qobject ...
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30 views

Error's while retrieving data from postgres to Qgis using python?

This is my code of python in qgis from qgis documentation docs uri = QgsDataSourceURI() uri.setConnection("localhost","5432","gis_data","postgres","vajja") ...
2
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1answer
73 views

QGIS 2.10 with ubuntugis dependecies Grass issues Ubuntu 14.04

I saw in How to correctly install QGIS 2.8.3 with GRASS plugin on Ubuntu 14.04? how to get Qgis 2.10 running from the non ubuntugis repository with grass features but I'm still having problems with ...
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1answer
21 views

Creating a new layer from a spreadsheet and an existing shape file in QGIS

I have a map of US zip codes and a spreadsheet that associates data with specific zip codes. I want to show the zip codes where the most data exists using a gradient, but I am not even sure how to get ...
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28 views

GIS route creation from street names

I have a list of streets comprising 300+ routes. Each route (in text) lists 4-5 street names where the route should take place. I would like to create each route, that is, plot the street names and ...
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2answers
27 views

Combining several mask rasters to obtain one single mask with binary values

I have a series of separate rasters which represent the cloud cover over the same area but in different months. Each raster has 2 values: nan for "no cloud" and 255 for "cloud". What i want to do is ...
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1answer
41 views

PostGIS Query returns duplicated rows

I'm trying to create a shape file of a state. I have a map of US zipcodes that I downloaded from the US Census and I want do create a shapefile of zipcodes in Florida. I ran this query which ...
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1answer
26 views

Cartogram not working: “Cancelled by user” - Why?

I am using the QGIS Cartogram plugin, but unfortunately something is not working as it should. First, the demo works just fine. But when I want to create a cartogram with my own layer. But as soon ...
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1answer
54 views

QGIS 2.10.1-Pisa [duplicate]

Since the version QGIS 2.8, each time I start to open it it begin wth this error message. I have Mac OS X 10.7.5 MacBook Pro, late 2011. It works but what do it means, and what should I do, I install ...
2
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1answer
21 views

Is it possible to open WMC(Web map Context) file in QGIS?

I am new to WMC and in our application we had a requirement to extend the WMC functions. For that I need to know whether QGIS have the support of WMC files. Or we need any plugins for WMC support ...
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0answers
31 views

Qgis delimited text layer from an excel file converted to .csv

I'm trying to add a delimited text layer using coordinates. The file has been created in excel and then converted to a csv file in the saving. When I put it into Qgis it doesn't recognise the ...
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2answers
108 views

Exporting .csv file as .shp in QGIS?

I am a newbie to QGIS. Here's what I'm trying to achieve: Step 1: Load the required GIS layer (*.shp file) Step 2: Load the .csv file in QGIS Step 3: Perform the join based on common attributes ...
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1answer
15 views

Error while displaying qgis project via qgis2leaf plugin?

couldn't see the map on the browser while using QGIS2LEAF Plugin in QGIS 2.10 Pisa. It gives error on web page saying: error at line 8: L is undefined. Please let me know if anyone knows the ...
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0answers
25 views

Is it possible to interact with a running instance of QGIS from the command line?

I just started looking at QGIS on MacOSX. I installed the MacPorts package and found the executable: /Applications/MacPorts/QGIS.app/Contents/MacOS/QGIS* Unfortunately it appears that the command ...
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1answer
59 views

pixel values beyond valid range in QGIS

I opened a sub-dataset of an HDF file (NDVI layer of MODIS HDF file) in QGIS, but pixel values are beyond the valid range (-2000,10000). I see many pixels way less than -2000 and way over than 10000. ...
2
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1answer
36 views

Difference between qgis.utils and qgis.core?

Please, can you tell me what is the difference between qgis.utils and qgis.core ? I'd like to understand step by step the QGIS API Document.
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1answer
49 views

Error while connecting qgis with postgres?

sql="select long,lat from poidata.poi_ca from where city LIKE '%unnyvale'" uri = QgsDataSourceURI() uri.setConnection("localhost","5432","gis_data","postgres","vajja") ...
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0answers
56 views

QGIS does not display all Features of Layer and behaves weird instead

I have a weird problem with QGIS trying to load a Layer from a Postgis Database When I open the Layer from Postsgis I have two choices: Method one: Either, I use the Panel "Browser", where I can ...
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1answer
55 views

Need to include GPS data in a GIS system

I work for a small telematics company and we received a request from one of our clients about integrating their vehicle GPS locations to their ArcGIS system. Our current system simply displays this ...
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1answer
32 views

CategoryList attribute for predefined color ramp in pyQgs

I am trying to style my vector layer in QGIS using the following python code: layer = iface.activeLayer() myStyle = QgsStyleV2().defaultStyle() defaultColorRampNames = myStyle.colorRampNames() ramp = ...
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24 views

Creating Origin Destination Matrix from Station Locations

I am attempting to create an origin destination matrix in python for all of the London Underground Stations. I have the station name and the lat, lng of its location. It is in the following csv format ...
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0answers
19 views

Export Feature with attribute to dxf

I'm trying to export features with at least one attribute to dxf, is that possible? E.g. I need the name or layer name of the feature in the CAD application.
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1answer
55 views

Presentation of terrain and sub-terrain data in 3D using Qgis

I have DEM of karst and .shp files of caves in that area exported from "speleoGIS" Therion http://therion.speleo.sk/ Qgis2threejs is amazing in making visualisation of 3D sourface, which is easy to ...
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0answers
76 views

Tree counting using LiDAR data

Does anyone have any ideas on tree counting using lidar point data? I have a small set of lidar point data (plantation area about 500 hectares), from which I want to collect number of trees per ...
2
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1answer
38 views

Show Log of the Sql statements that QGIS generates to retrieve Data from Postgis

Is there a ways to - make QGis log its generated SQL Statement or to - force POSTGIS to log all interaction with QGIS? There is something strange happening to the WFS layer I retrieve in QGIS, since ...
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0answers
15 views

Rendering problem in qgis

I have fetch data from database and draw it on qgis 2.8 as vector layer it works fine with limited data but for large data it will not work and goes into not responding stage, I am unable to ...
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1answer
15 views

QGIS Relations loss of form style

I'm currently creating a project for management of highway drains in QGIS which involves the recording the feature attributes and logging of multiple inspections against a feature. I have a layer for ...
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1answer
36 views

What data format to do temporary editing with QGIS before committing it to a RDBMS?

I am trying to create a temporary spatial data from a PostGIS database that a user can do the editing on. Currently, I have a service that returns GeoJSON from the PostGIS database. But I don't think ...
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1answer
34 views

Rule based labels using QGIS?

I couldn't find an option of "rule-based"-labeling in QGIS 2.10. For example that big cities are also labeled bigger than smaller cities. Am i missing something or doesn't it exist?
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0answers
27 views

Inputting Longitude and Latitude in CSV from Geotagged, Photo Coordinates (WGS 84)

I am trying to take Geotagged picture coordinates and put them into a CSV file to display in QGIS as point values. Using Picasa, I can see that the picture coordinates are in the correct locations on ...
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0answers
13 views

Is it possible to set up the atlas coverage layer to automatically clip other layers contained in the project?

Lets say I have two layers, one with county limits and another with roads for that same area. I'm trying to set up an atlas with counties as the coverage layer, so that I get a set of maps, one for ...
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0answers
32 views

Snapping points to polylines and maintaining minimum distances between the points as well as meeting other parameters

I have thousands of locations that I would like to snap to be placed on top of a hundreds of polylines based upon matching attribute fields. Think of them exit signs located on every ...
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0answers
24 views

How to write a loop selection by location and export in QGIS?

I would like to be able to make selections in sequence between buffers and surrounding areas. This would lead to areas (polygons) being selected repeatedly by 2 or more buffers and I want to be able ...
2
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1answer
37 views

I tried to run QGIS using python but I couldn't get any output on screen?

uri ="C:/Users/rajagopalv/Desktop/poi_sunnyvale.csvdelimiter=%s&xField=%s&yField=%s" % ("|", "x", "y") vlayer = QgsVectorLayer(uri, "address_sunny", "delimitedtext") ...
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0answers
9 views

QGiS 2.8.2 Graduated style symbology [duplicate]

I'm having trouble inQGIS with the symbology. I can classifify and categorized my data. But i cannot with the graduated symbology? I've try different format in Excel. And i cant find the problem ...
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0answers
32 views

How to show two layers at the same time in Qgis

I have a question about Qgis layers. I want to see two layers at the same times. one is lines which are boundary lines and the other is polygon which are district. when i was surfing about this ...
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1answer
38 views

Is it possible to import .ecw images into QGIS 2.10 for UBUNTU?

We want to import .ecw images. We have done it using QGIS 2.8 for Windows in the past, but we can't using QGIS 2.10 for UBUNTU. Thanks.
2
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2answers
89 views

Problem with PostgreSQL View layer in QGIS

I have a PostgreSQL table and view: CREATE TABLE lines ( geom geometry(MultiLineString,4326), type character varying(254), login text, gid serial NOT NULL, ...
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0answers
12 views

How to SetVisible a layer without redraw all the mapcanvas

I am working with QGis 2.8.2 API c++/ QT 4.5 I am displaying a lot of layer in a mapcanvas, I am looking for a method like setVisible(boolean ) in order to setvisible or not a specify layer ...
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5answers
139 views

GPS Track Editor to crop tracks with select by clicking start and end points

I'm trying to take a bunch of gps tracks of mountain bike rides and turn this in to a trail map. I want a single track for each trail. I'm looking for an editor that will allow me to select a ...
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0answers
40 views

CSV file locked for editing after join

I have created a table join between a vector shape-file and a csv file using pyQgs. Now i want to edit the csv file (not from inside QGIS) . But when i double click on the csv file , it says that ...
2
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1answer
33 views

How to calculate the form (or shape) factor of a polygon?

I am using QGIS to calculate the form (or shape) factor of polygons following what Louf and Barthelemy did here: http://rsif.royalsocietypublishing.org/content/11/101/20140924 The form factor is ...
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1answer
35 views

QGIS export attribute table to csv and keep value relation

If i export my joined table to csv i get the numeric id value instead of the value relation name from the joined table. Can I export my table with the value relation value? Best regards
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0answers
34 views

Calculating minimum distance using “Distance Matrix” in QGIS

First of all, I'm very rookie in using QGIS. I want to calculate minimum distance between points and a line in QGIS. I use "Distance Matrix", point shape file contains 1337 points data, and I made ...
2
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1answer
63 views

How to add loading bar in QGIS Plugin development?

Every time i use tool or plugin in QuantumGIS, i saw a kind of bar like this for indicating loading progress : The different between that bar and Progress Bar is that progress bar will increase ...