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

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How do you modify selected geometry with a function in qgis python console?

My example use-case is that I want to redistribute vertices along lines as in Redistribute linestring vertices to specified distance and I've written some functions to do some of the work: import ...
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0answers
62 views

QGIS 2.4: plugin changes map tool canvas click behavior from 2.0

I had created a plugin for QGIS 2.0 to add new features more easily. It involves changing extents and updating snapping options along with triggering the default actionAddFeature(). However, I've ...
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70 views

distance difference in Google Earth with exported GPX or KML compared to source shapefile

I've converted a shapefile (points) to KML with QGIS. Points in the shapefile are within 100m distance from each other. When I measure it in Google Earth, the distance changes to 80m. The same ...
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1answer
225 views

QGIS Updating composer label text via python - problem with Item Properties panel

I am writing a plugin that replaces the text of a composer label based on its itemID. When I change the text of the label using: item.setText("Hello World") the label changes on the composer but ...
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1answer
9 views

QGIS 2.4 Attribute Table Search Bar?

I am learning how to use QGIS and am following various tutorials. My version of QGIS (2.4) does not have a "look for" search bar in the attribute table window as seen in older versions in screenshots ...
4
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1answer
139 views

QGIS 2.0.1 linking table issue, MSSQL 2008 database

I'm trying to link tables in QGIS 2.0.1 and MSSQL 2008 database. I can link them but when I try to open the attribute table QGIS throws an error and shuts down creating a *.dmp file. I saw that ...
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2answers
1k views

How to split a polyline into points at certain intervals?

I am trying to split a polyline into points with 2m intervals in ArcGIS but I don't have the necessary license. Is there a way that I can do this in QGIS? Context: I have drawn a hypothetical lake ...
2
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1answer
25 views

How to do loops on raster cells with python console in QGIS?

I'm new here and beginner with python. I'm looking for a solution to my problem for some hours but now you are my last chance... I'm using the python (2.7.5) console in QGIS (2.4.0). Is there a ...
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2answers
65 views

How to convert data from a .gdb into a shapefile without ArcMap?

I have a .gdb folder with LOCK Files, FREELIST Files, ATX Files, GDBINDEXES Files, GDBTABLE Files, GDBTABLEX Files and, SPX Files. I want to convert the parcel data within this folder into a ...
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7 views

Obtain an altimetric map from a layer with lines

I have a layer with contour line and I need a map with polygons colored in funzione of altitude. It's possible in arcMap, it's also possible in qgis? Thanks!
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23 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 ...
3
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1answer
44 views

How to display bidirectional flows?

I'm working on a map showing oil shipping. Basically, I have a a series of nodes/line segments that make up the shipping network. I've joined the sums of oil that traveled along each node, so can ...
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1answer
21 views

python qgis 2.4 : display a view with symbology

I have managed to display a view created using postgresql from qgis using python code: uri = QgsDataSourceURI() uri.setConnection("localhost", "5432", "stat", "postgres", "admin") ...
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1answer
14 views

How to export drivingDistance results in pgRoutingLayer on QGIS 2.2.0?

Hi and first of all congratulation for the great work on working and explaining the posGIS functions in QGIS : it makes this rich GIS enven richer. Thank's to Underdark's pgRoutingLayer extension, I ...
21
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3answers
3k views

What do I need to know, to develop a plugin for QGIS?

I wish to develop a simple plugin for QGIS, which will open some data, and some specific processing. I have quite a it of development experience with ESRI's Arcojects, but haven't developed with QGIS ...
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1answer
96 views

How to creat multiple rings between two circular buffers?

I am working with mathematical-ecological modeling and I am also a new user of QGIS Software. First I am creating 3 circular buffers with same center (shape center) covering a region with roads (shape ...
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0answers
18 views

Features in .shp can't be identified & won't render

Using QGIS 2.4.0 on Windows 7 Service pack 1. I have several .shp's, all polygons, that give me the following problem: 293 features are listed in the metadata and shown in the attribute table but the ...
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1answer
86 views

Using Union on multiple shapefiles to output single result

Using QGIS 2.2 and Python, I would like to use the Union algorithm on multiple shapefiles (contained in a folder TEST) which would then produce single shapefile containing all the data. Currently ...
2
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1answer
39 views

Not able to save edits to vector layer in QGIS

I have a vector layer with about 200 features. So far I have been able to add polygons to this layer just fine, now it is giving me trouble. When I draw the polygon and try to save edits, the polygon ...
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1answer
19 views

Merge multiple linestring features into a single multilinestring

Using QGis or ogr2ogr how do I convert a vector file containing multiple linestrings features into a single multilinestring feature? At the moment I've been doing this manually by converting the data ...
2
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3answers
99 views

How to highlight polygons within another polygon?

I want to symbolize public buildings in OSM data. For Example: There is a polygon and in column "amenity" it has the value "school". But i don't want to highlight this polygon, but the buildings ...
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0answers
11 views

Add a new polygon to an existing shapefile from wkt in QGIS

I have a layer of polygons in QGIS; I want to add programatically (pyqgis) a new polygon to this layer using WKT. Example: mywkt = POLYGON ((522762 376413 0,530635 368671 0,522237 353713 0,522762 ...
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32 views

Editing the QGIS Attribute Table

Is there a way to edit the name, type and length given to each column on the attribute table once the information has been imported from Excel?
4
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2answers
515 views

Where has the cartogram plugin for QGIS gone?

This plugin used to be downloadable from Carson Farmer's plugin repository page. However, the repository is broken. An old version of the plugin source code is still available at ...
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0answers
11 views

QGIS custom labeling by clicking on polyline (and polygon)

QGIS has now few really good options for custom labels but I can't find a way how easily manage labels along polylines. Is there any tool which helps me to place labels by clicking on polyline so the ...
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5 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 ...
3
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1answer
48 views

Saving selection as new layer in QGIS 2.4?

I've selected a number of polygons from one layer and want to create a new layer. Because I can't right click using a mac how do I find "Save Selection As". Its not in the list in the "Layer" ...
2
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2answers
170 views

What is causing this distortion in QGIS georeferencer results?

When importing a JPG map using QGIS's georeferencer plugin, the resulting map layer is distorted and does not look anything like the map that I am trying to import. I can't work out what is causing ...
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59 views

what happens to attribute table while performing union, intersection, difference of gml and shp file in QGIS

I am trying to do an analysis of the data conversion from shapefile to GML file using QGIS. For the analysis I have taken a point, line and polygon file. I first took a shapefile and converted it into ...
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1answer
64 views

Interpolation without a point layer in QGIS

I have a vector layer with incidence data (i.e. frequencies) and I made a graded color map from this using the above frequencies. Now I am looking forward to creating an interpolated (kriging) map ...
3
votes
1answer
88 views

Continuous color band for a raster legend in QGIS composer legend

I'm looking for a way to insert continuous colour legend for a raster layer. I managed to create discrete symbols with values along the bar, but I would like to have a continuous bar with some values ...
3
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2answers
893 views

Can I fix 'qodbc3:unable to execute statement' when querying SQL Server 2008?

I was testing features of QGIS and its really cool.I tried to query each table using right click and query but I can't query sql server 2008 database : Error: An error occured when executing the ...
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0answers
21 views

Create global raster layer with latitude values of each cell in QGIS

I have a raster with a 0.0083 degree resolution (WGS 84) of which I need the area of every single pixel. An easy but compute-intensive approach is explained here but as I need to work with bigger ...
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2answers
33 views

Error while importing CSV File using PyQGIS

Currently I am trying to import a CSV file using the python extension in QGIS and I have run into a problem that I can not seem to solve. I am trying to do a basic import of a CSV file from a python ...
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0answers
41 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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0answers
60 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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1answer
116 views

Pull pixmap image source from ui edit text in QT

I'm putting together a custom form for QGIS identify using Qt Designer. One attribute has a file name to the accompanying photo of the feature. I'd like to have the photo label in the form grab the ...
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0answers
32 views

Ripley's K function Interpretation, and another R questions

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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0answers
15 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 ...
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1answer
46 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 ...
0
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1answer
47 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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2answers
289 views

How do I successfully install the LecoS plug-in for QGIS 1.8

I have been trying to follow the instructions given here, but repeatedly get an error message pop-up titled "Mount" stating Access is Denied. Does anyone have a solution please?
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0answers
10 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. ...
5
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2answers
2k views

How to install QGIS on Centos 6?

I'm new on this; I really tried a lot before ask.. but nothing works. I did all that the qgis page says. Install ELGIS. after that i investigate and tried diferents comands.. but nothing works..the ...
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1answer
899 views

Yum Install QGIS on CentOS 6

I was trying to install qgis on centos 6.3 and follow the instruction here. However after running yum install qgis qgis-python qgis-grass qgis-mapserver I got below errors: ---> Package ...
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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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16 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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0answers
9 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 ...
3
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2answers
301 views

WMS layers don't draw in QGIS or ArcMap but do in OpenLayers

WMS Map was published by myself in AutoDesk Infrastructure Map Server 2013. I can connect and load detials (properties / metadata) in QGIS Browser, ArcCatelog. I can load the wms into QGIS desktop and ...
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25 views

Points generated using mmqgis are invalid

I used mmqgis plugin to geocode some addresses, he pointed to have found them all. But the screen shows only a point when there are more than 100, in the attribute table all appear. I loaded this ...