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

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18 views

Can QGIS hyperlink polygons to link with a server?

I am trying to hyperlink a load of polygons to a set of files on a server (using the actions on QGIS). However, I can only seem to be able to link to files when they are either in by C: or online. Is ...
3
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61 views

Sourcing GIS data from First World War (WW1)?

Simple question, but does anyone know where I can get some detailed (eg 1:10m scale) vector data from the First World War? I've been through the archives here, but it seems the best sites for it ...
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10 views

QGIS web client: “Object Identification” initially toggled on

I'm running a QGIS web client and a QGIS server. I want to modify the initial settings of the QGIS web client so that the "Object Identification" mode is toggled on from the beginning (just like ...
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1answer
48 views

Georeferencing image using QGIS?

I am very new at this and when I georeference an image in qgis, I get the same image georeference but rotate and elongated. I use 3 control points to georeference the image but whatever I do, I get ...
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0answers
11 views

Is there any autocomplete filter widget for QGIS connecting to PostGIS?

In QGIS, there is Value Relation widget for fields, that contain references to data in external tables or views. While it works fine for small number of choices, it can quickly become overwhelming, if ...
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13 views

How to get sql error from postgis when a plugin fail to load vector layer?

I am writing a plugin for qgis that load a sql layer from postgis database. I am disappointed that when the layer fails to load i can't find a way to get the sql error message from database server. ...
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0answers
18 views

How to compare two sets of points in QGIS?

I have two point layers with XYZ data: 1 set are points measured at the field and the second set is a Lidar data set. I want to check the accuracy of the lidar in comparence to the measured data. Is ...
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28 views

Reading Points as PolyLines

I'm currently developing an Android app where I need to show some information on a map, which is stored as Shapefiles (.shp + .shx + .dbf). I noticed that when the shapefile is opened in QGis, a nice ...
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14 views

More than two level group on Lizmap WebClient

i can see level more than two group on lizmap plugin, but when i save for webClient, it just appears two level group on Lizmap WebClient legend layers area. i want to see on Lizmap WepClient like ...
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0answers
19 views

Import QGIS Python modules in Python command line or standalone script

I am running a Windows 7 machine with Python version 2.7.8 (32 bit). I installed QGIS 2.4 (Chugiak) from OSGeo4W and simply want to be able to import the QGIS Python modules (e.g. qgis.core) into ...
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24 views

Polygonize only pixel values of 1 from a raster

I have a raster mask that I have created in QGIS (2.2.0) that consist of 0, 1 and nodata values. I would like to end up with a polygon dataset that consist of only the value of one pixels from this ...
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1answer
48 views

Determining direction of longest segment of polygon?

I have a shapefile with 9000 agriculture fields and what I like to do is to determine for each field (=each polygon) the direction of the longest segment. For instance, the selected polygon in the ...
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2answers
25 views

How to extract a new linestring vector from a existing multipolygon in QGIS?

What I want to do: create a new line (named linestring in Postgis?) from existing multipolygon layer in Postgis. Purpose: once these lines are created, I'll run some distance calcs from specific ...
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2answers
51 views

Generating polygons with shared boundaries using QGIS?

Essentially the problem is that if you digitise each polygon separately the boundaries will not match exactly. My instinct is to have a table of line segments and generate the polygons from that using ...
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1answer
22 views

qgis printcomposer: can I select features whose attributes to show

I am using the atlas to generate a number of maps. Each map is of a particular zone represented by a multiline vector layer. I have another layer with point data and each map has an attribute table ...
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1answer
14 views

qgis printcomposer: can I wrap text in attr table?

I have some longish text attributes and when I try and put these on the map using the attribute table they get truncated. Is there a way to get these long lines wrapped.
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1answer
27 views

Have Atlas sorting and filtering controls been removed in 2.4?

In this diagram the atlas generation tab of the print composer has several controls that I don't see in my version (2.4) of QGIS. In particular the feature sorting and feature filtering, both of ...
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27 views

QGIS formats support [closed]

Is there any plugin or any feature which will supports more formats than existing formats. Because ARCGIS has Data interoperability tool which can support same as FME Formats. Is there any thing ...
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1answer
25 views

ESRI : 54019 or World winkel II in QGIS

Currently I didn't find World winkel II or ESRI : 54019 coordinate system support in qgis. One of our client using this.. Can any one tell me a solution to load shape files,which are using his ...
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1answer
23 views

How to Manually add a Z variable in Qgis onto a vector layer

I am trying to manually add one constant Z-variable (e.g. 200meters) across an entire Vector Layer in Qgis so that I may eventually use the Interpolation plugin to generate a Tin. I have not been ...
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1answer
24 views

What causes this error when loading plugin

After installing pyspatialite on my Mac two plugins fail to load with this error:: This plugin is broken invalid literal for int() with base 10: '2-spatialite' I am fairly sure that the offending ...
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3answers
32 views

How to convert crs projection of Map in qgis

I am totally new to GIS. I have a qgis project. I am adding the screenshot. As you can see the map is sort of rectangle in projection. How can i project it like this (without the grids) Thanks ...
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1answer
33 views

What's the difference between Processing GRASS and the GRASS toolbar?

Preparing a QGIS-course for my colleagues I stumbled over the following question: What is the difference between the GRASS commands in the processing toolbar and the GRASS Tools, that you access via ...
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1answer
78 views

Is there a gallery of QGIS maps anywhere?

Specifically, I want to see the gorgeous map of Chugach State Park that you see when starting QGIS 2.4 "Chugiak". Is there a website out there where people share maps? I would like to share and see ...
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34 views

How to aggregate data which meet certain conditions using QGIS?

I have a point shapefile with meteorological stations which contains three columns, which are: Date: The date on which the measurement has take place (it covers a range of ten years) Id: The ...
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0answers
17 views

Qgis crashes when moving layer with many features [duplicate]

The qgis does not respond and crashes and I can not do what I need. I tried on minimum hardware requirements but have not found. I'm on a core i7 with 4gb memory windows 7, Any tips?
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13 views

Is there a limit to the number of polygon points you can export to CSV in QGIS 2.4?

Using QGIS 2.4 I am currently importing a csv file with ~30,000 polygons (polygons in WKT format). I also have a United States shapefile. I have used the Clip function to get only the polygons that ...
3
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2answers
77 views

LiDAR data density, returns per square meter

How can I compute a raster showing the number of return points per square meter using SAGA GIS or other open source software? My goal is to obtain a mask which would show me the places (cells) ...
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0answers
26 views

Link to pdf file through mouse clicking

I need help in identifying the feature attributes displaying a pdf file when click in that feature. I see many examples but I don't have success. I try this code: command = "firefox"; imagerelpath = ...
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2answers
31 views

How to export a high-res world map image?

I'm trying to get some (very) large world map images (think 10k x 10k pixels etc), but can't seem to do it with QGIS, and would appreciate any help. Manually adding smaller images to a larger one ...
2
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1answer
25 views

How to subtract lines with thickness from polygon

I have a polygon and some lines crossing it. I want to subtract the lines with a certain "thickness" from the polygon, so it splits up into various polygons which do not touch each other anymore. You ...
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0answers
46 views

How to create a vector layer from a GeoAlchemy2 query?

I'm currently developing a QGIS plugin where I mapped a PostGIS database via GeoAlchemy2. I wrote a function that returns results from a GeoAlchemy query but have no idea how to create a vector ...
3
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2answers
15 views

QGIS Line End Caps

When styling a road network where all sections of the network between junctions are separate paths, I style the ends of the lines to rounded to remove any gaps that might appear where the joins are at ...
2
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0answers
55 views

Doubts with Ripley's K function Interpretation

I'm a self-taught person, I'm studying the K Ripley's function and I would need some person who give me some advices. First, I have written a little script of R in QGIS processor: ##Point pattern ...
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1answer
51 views

Issues calculating range with QGIS 2.0 raster calculator

I would like to calculate a simple range using the QGIS 2.0 Raster Calculator, but am getting strange results. I believe I am not using the correct syntax. To get all values between .003-.5, I ...
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2answers
37 views

How to calculate x/y in a different coordinate system in QGIS 2.4?

I'm trying to calculate Northing Easting in QGIS. I can get it to calculate my lat/long using $y and $x in the field calculator. I changed coordinate systems to what I want it displayed at, but it's ...
3
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1answer
38 views

Does QGIS automatically use spatialite spatial indexes?

When you write a query in spatialite you have to manually join your query to the spatial index for that index to be used to speed up the query. When QGIS displays data does it take advantage of any ...
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0answers
16 views

How to create correct vector grid in meter

I want to create a vector grid, with squares of 100x100m but have some serious trouble in solving this apparently easy task. I already read all the posts, but didnt find a good solution. Here is what ...
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1answer
27 views

How to split Polygons by line grid?

I want to split a polygon by a intersecting line into different parts, exactly like in this post(Qgis - Is there a way to split a polygon layer with a line layer?). I have a vector grid to cut the ...
1
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1answer
17 views

Python Error while installing Cartogram

I am quite new to GIS and qGIS especially. I would like to install cfarmers cartogram plugin. From what I understand, this has to be done manually - so I 've followed the instructions from ...
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0answers
18 views

How to write a custom map canvas item by subclassing QObject and QgsMapCanvasItem?

I'm writing a QGIS python plugin where I place some QgsVertexMarkers on the canvas like this: marker = QgsVertexMarker(self.canvas) marker.setCenter(QgsPoint(point[0],point[1])) Now i would like ...
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0answers
27 views

How to select duplicate polygons? [duplicate]

Although it may seem this has been answered before, there doesn't seem to be a solution. I am trying to simply select duplicate polygons. I don't want to delete them or anything like that. I need ...
2
votes
1answer
44 views

Is the csv handling in QGIS bugged?

I am using QGIS 2.4.0 and sadly it seems that QGIS imported csv files are somewhat bugged. I cannot use imported csv files the same way as shapefiles. It seems that sometimes it is easier to import ...
3
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1answer
50 views

Is it possible to use comments in QGIS Query Builder?

I am trying different queries in the Query Builder. Is there a way to comment the query? I tried with /* */ # -- without success : An error occurred when executing the query. The data ...
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0answers
15 views

Exporting ArcSDE feature class to shapefile using OGR?

I'd like to export data from ArcSDE for SQL Server to SHP. I've tried first to run this python script in QGIS: http://trac.osgeo.org/gdal/browser/trunk/autotest/ogr/ogr_sde.py But finally I've got ...
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2answers
51 views

Tool for rendering/drawing maps from coordinates

What tools can be used to convert a set of coordinates into polygons? For example: this code represents a room by providing information about it's four corners. <node id='-202' lat='41.015146' ...
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1answer
31 views

Merging vector layers using QGIS? [duplicate]

I have dozens of vector layers that I want to join together in QGIS. They have identical fields. How do I do this?
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0answers
15 views

QGIS startup error (symbol lookup error, undefined symbol) after system update

I'm using QGIS 2.4.0 on Linux Mint 16 MATE 64-bit. This afternoon I did a normal system update via apt-get update && apt-get upgrade followed by apt-get autoclean && autoremove. But ...
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0answers
12 views

Why is there greyed dupplicated table in Add PostGIS Layers dialog in QGIS 2.X

Does somebody knows why PostGIS 2.X tables are duplicated and greyed in the "Add PostGIS Layers" dialog in QGIS 2.X.? One is coloured with geometry type recognised the other is greyed with unknown ...
3
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1answer
36 views

How to replicate the QGIS vector smoothing effect in ArcGIS?

You can see from the screenshots that QGIS has, in my opinion, much more pleasant on-screen rendering of vector features. I assume there is some sort of smoothing algorithm used in QGIS. Is there a ...