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

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1answer
129 views

QGIS Polygon overlaps on “Merge Shape file”

I am trying to merge two polygon shape file in QGIS 2.6.1. One is older one with all state boundary, which I have (.shp, .shx, .prj, .dbf). New one is downloaded from WEOGEO (.shp, .shx, .prj, ....
3
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1answer
102 views

Finding roads in one particular province of The Netherlands using QGIS?

I have two shapefiles that I want to use to see all the roads in one particular province of The Netherlands. So I have one layer with all the roads in The Netherlands and one layer with the ...
1
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2answers
107 views

Transform from artificial coordinate system to a real one

I have spatial data generated in an Archaeological excavation which is in an artificial coordinate system and I want to convert it to a "real" coordinate system. To do this I took real coordinates ...
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0answers
25 views

QGIS - Label polygon with different projections

I have a polygon layer projected in an UTM. In properties I checked 'show all labels for this layer'. Does anyone know why the label does not show until zoom 15:1 in QGIS with CRS-4326, while in ...
2
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1answer
726 views

How to add label to QgsVectorLayer by Python

my goal is to define label programmaticly for the case similar for the figure below: But didn't find any guidance how to do so using Python. I have a feeling it could be done using QgsLabel but ...
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0answers
48 views

QGIS attributes disappeared when reopened shapefile

I'm a new QGIS user so sorry if this sounds lame. Working in QGIS, I've built a vector layer and added attributes. When I reopened the file this morning, the attributes won't show up in the ...
0
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1answer
117 views

Is there a difference between the two sets of QGIS terrain analysis tools?

Is there a difference between Raster/Terrain Anaylsis and the same features in Raster/Analysis/DEM (Terrain Analysis)? The two appear to do the same types of computations; are they the same or is ...
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0answers
58 views

What is the background processing of rainfall thresholding?

I want to create a flood map using Quantum GIS. First of all I create catchment area (flow accumulation). Then, I delineate a Channel Network by applying a threshold to flow accumulation. So I want to ...
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0answers
78 views

Generating ESRI compatible raster reference files in QGIS?

Backstory: employer is GIS incapable and most of the data we work with doesnt play nice with GIS software. That said, we have a client who is very GIS oriented. My boss (not my work) is providing them ...
2
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1answer
73 views

Cache - how to give QGIS more?

Another question... how do you increase Cache size? think QGIS is falling-over as haven't given it enough... image to export 1080 x 800 mm! would like at least 120 dpi or 200 : ) Many thanks, Cas
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2answers
31 views

QGIS - seem to have killed my 'Items Properties' panel

QGIS 2.6.1 Microsoft Windows 7 Relative Newbie to QGIS; old hand at drawing software Think I have corrupted this on my actual file that I'm working on. Yes, I know that I can right click and get ...
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0answers
63 views

QGIS creating contour lines ERROR 1 CPLRealloc() out of memory allocationg 416 bytes

When i try to create contour lines from raster (tiff file) in QGIS 2.6.0 Brighton i get the following message: I thought it could be irregular size of raster that causes error so i clipped it in ...
2
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6answers
978 views

How to export attribute table with start and end coordinates of lines to Excel?

I am working in QGIS. I have a georeferenced line layer and I want to export the attribute table and the coordinates of start and end points of my lines to Excel. Can I do this with QGIS?
2
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1answer
234 views

How to add multiple attributes to a newly created feature with PyQGIS

I am creating a form for updating the attribute values of the newly created feature. But when i am updating the values only one attribute field is getting updated. So if i want to update the multiple ...
4
votes
1answer
1k views

Does mapCanvas().refresh() not work in QGIS 2.6?

Before I used the function qgis.utils.iface.mapCanvas().refresh() to reload the map canvas after for example a layer color was changed from a plugin. But this is not working with QGIS 2.6 for me. ...
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1answer
382 views

How to export only certain column from selected feature to csv file in QGIS using python code

I have selected features in QGIS, I want to export only two columns from the selected features to a csv file automatically using python code. I have tried the following code: layer = qgis.utils.iface....
7
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3answers
1k views

How to define layer's CRS and avoid the CRS dialog in PyQGIS?

There is an existing Shapefile, which I want to add. At the moment my code looks like: self.iface.addVectorLayer(self.shpFilePath, "Track", "ogr") It works fine, but i want to define the crs ...
2
votes
1answer
237 views

Download file from network using PyQGIS 2.x

I have a python plugin targeting QGIS 1.8 that uses QgsNetworkAccessManager and QNetworkRequest to issue a GetCapabilities request to WMS servers. With 1.8 everything was working fine. Now we are ...
2
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1answer
297 views

Turn off the setting of QGIS to produce xml when closing

Every time I open and close a raster layer in QGIS it creates an xml file for that raster when closing. While I do a lot of automatic processing this really bugs me, since I have to add every time ...
2
votes
1answer
462 views

How do I unselect features in ONLY the current layer in QGIS

So, I hope this is an easy question, but: How does one unselect features only from a certain layer? I know there's the Deselect features from ALL layers button. But that's extreme. Is there a simple ...
2
votes
1answer
249 views

Creating Isochrones with pgrouting - Network set up, locations (from point shapefile) imported into PostgreSQL/PostGIS DB and now?

I want to calculate isochrones representing the accessability of certain locations in a city. So I have set up the pgrouting enabled database, imported the OSM-Roads and created a network (thanks ...
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1answer
1k views

Merging polygon and line shapefiles into one using QGIS?

I have two shapefiles: One is a line feature of the rivers and waterways of London, the other is a polygon feature of the reservoirs, lakes and ponds of the same area. Is it possible please to merge ...
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0answers
28 views

Exporting route from QGIS Roadgraph plugin?

I've created a route with qgis roadgraph plugin, and I want to create a shapefile (line) from this. I've tried with export, and save as .shp, but the new shapefile doesn't show the line!
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1answer
891 views

Creating point to lines intersection in QGIS?

I have two line layers, and I want to create a point where they cross each other. How can I solve it in Qgis?
0
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1answer
112 views

What's the PostGIS equivalent to Extract Nodes in fTools / QGIS? [duplicate]

I'm looking to convert Park polygons from OSM into points. The QGIS fTools Extract Nodes tool will convert a polygon to points at the vertices. What is the equivalent function or work-flow in ...
1
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1answer
47 views

QGIS multiple whitespace in attributes are removed after restart [closed]

Concerning this question: http://stackoverflow.com/questions/28660079/firefox-is-ignoring-more-than-one-whitespace-in-svg-text-and-showing-them-smalle I have an issue with the saving of Strings with ...
4
votes
1answer
834 views

How to compute average slope and area-weighted average slope?

I am learning GIS for use in hydrologic analysis. Related to computation of overland flow there are two types of slope that I would like to be able to obtain from GIS. The first is average slope for ...
2
votes
1answer
459 views

Can't open projects with qgis. Why? What i have to do?

I have an essential problem with QGIS, that I had both with version 2.2 and now with 2.8. I can't open the projects that I have saved. It is a project of 4 layers: a vector with a region of Madagascar,...
1
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1answer
159 views

extract 1st level boundaries from GADM worldmap in QGIS

I need a world map, broken down to GADM 1st level. The obvious way would be to download all single country .shp files and merge them. But that is far too tedious of course. I tried the dissolve ...
1
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1answer
43 views

Is there an out-of-the-box way to manage 1:n data in QGIS?

I think an image explains the question best: What I basically want to do is select the object, view its attributes and from there call the second table to view/edit/add status entries. Since I can'...
10
votes
1answer
584 views

Adding new menu item to QGIS Desktop app?

I need to add new menu item to the top level menu of QGIS Desktop (2.7.0); I.e. it shall be on same level as "Project", "Edit", "View", "Layer" etc. As far as I know there is pretty nice way how hide ...
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2answers
264 views

Shapefile to KML Conversion Problems in QGIS 2.6.1 on Mac

I am currently using QGIS 2.6.1 on a Mac with OS 10.9.5. I am trying to export a shapefile using QGIS to KML format. I am having success with the export but the data is skewed halfway across the ...
0
votes
1answer
124 views

QSpatiaLite Plugin: LINESTRINGZ(x y z, …) supported?

I get an error when trying to import this query as a spatial table in QGIS: select geomFromText('LINESTRING Z(13.091464 47.061328 2597, 13.092059 47.061287 2580)') as geometry 'The result can't ...
2
votes
1answer
369 views

How to check the value of a single pixel in QGIS?

I was wondering how to check the value of a pixel at a mouse click in QGIS (as of 2.4). In ArcGIS, the "Identify" tool does the job for both rasters and vectors. However, in QGIS, the "Identify" tool ...
2
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0answers
40 views

QGIS Python Script for RoadGraph plugin

I am looking to create a Python script that will take X,Y coordinates from one field in an attribute table, compare them to another set of X,Y coordinates in a different field, and populate a field ...
2
votes
1answer
256 views

Issues with PyQGIS while running a QgsZonalStatistics script

I have experienced a very bizarre issue with my PyQgis code. I simply want to load a raster and a vector layer to do zonal statistics, the first part works perfectly but for the zonal statistic I have ...
1
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1answer
603 views

How to use Delaunay triangulation in QGIS?

I have to create a Thiessen polygon for a site in New Jersey and all I have right now is the concentrations from samples we took in the area. What else do I need and how do I input it into QGIS to get ...
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0answers
50 views

How to change the attribute values of the feature using the custom feature form

When i am using the following command it opens the feature form with all the fields: qgis.utils.iface.openFeatureForm(qgis.utils.iface.activeLayer(), f) But i want to open a feature form with the ...
2
votes
0answers
153 views

QGIS extremely slow to clip vrt on Mac

I've been using QGIS 2.6 (Brighton) happily for awhile but suddenly it became extremely slow during certain operations, after being reasonably fast in past use. I'm merging NAIP JP2 files to virtual ...
1
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0answers
142 views

Inflating the boundaries created with convex hull

I have a set of lan and lat points and have plotterd a convex hull for them using QGIS. A polygon is created along the set of points and plotting them on the MAP. Now I am trying to inflate the size ...
1
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2answers
80 views

QGIS dividing a raster by a polygons layer

I've got a raster image and I want to divide that raster by a polygon layer. There are just 7 polygons in the layer so i need to obtain 7 raster images as output. How can this done in QGIS?
1
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1answer
57 views

How to compute buffers for certain features?

I used the following snippet of codes for finding buffer. def buffer(self): layer = self.iface.activeLayer() distance = float( self.dlg.DistancelineEdit.text() ) city = self.dlg.Citycombo....
0
votes
1answer
204 views

How to connect mouseclick to map canvas in QGIS?

How to connect mouse click to map canvas in QGIS using python script? I have two lines of code to connect mouse click to map canvas: button.clicked.connect(self.onClicked) self.areapushbutton.clicked....
1
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1answer
149 views

QGIS/OpenLayers - How to add a “labels-only” reference layer (basemap focused on labels)?

In ArcGIS you can add a "reference basemap" which features labels for key locations as in: http://www.arcgis.com/home/item.html?id=8b3d38c0819547faa83f7b7aca80bd76 however, in QGIS, I cant figure ...
2
votes
1answer
98 views

How to visualize car park occupancy over time?

I am using QGIS Brighton 2.6.1. I have a csv table with the exact entrance datetime and exact exit datetime of every car in an specific parking. Example of table: Nº DateTimeEntrance ...
3
votes
1answer
131 views

How to import fromUtf8 in QGIS?

# Declare instance attributes self.actions = [] self.menu = self.tr(u'&City_searcher_plugin') # TODO: We are going to let the user set this up in a future iteration self.toolbar = self.iface....
2
votes
1answer
214 views

How to update Trackball controls at three js

I have a project at three.js created from qgis to threejs export where i need to update the trackball controls on window resize.. I need to do that updating the whole controls calling the function ...
1
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1answer
72 views

Keeping no data values in clipped rasters

I am using QGIS and I have a raster layer with temperature values. The ocean has "no data" values, since I need only terrestrial information. I need to clip this image to retain only one part of the ...
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0answers
121 views

creating composite raster tiles from multiple vector layers as new background map in QGIS

I have been patiently restyling OS Vectormap product to create a map background I'm happy with, which i want to now use as a background for a leaflet map using QGIS2leaf. I understand that performace ...
1
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1answer
99 views

Determining Projection using QGIS?

I am very new to QGIS and I am trying to determine the spatial projection and the units of distance of a certain raster file. The closest thing I can find is the CRS, which is set to some sort of ...