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3
votes
1answer
423 views

How to calculate the perimeter of the polygon using python programming

Is it possible to calculate the perimeter of each feature of the polygon? For calculating the area we are using: area=feature.geometry().area() is there any function to calculate the ...
5
votes
3answers
3k views

Misplaced Google Maps with OpenLayers plugin in QGIS?

I was using Google Maps with OpenLayers plugin in QGIS with my vector layer with projection EPSG:4326 with google map projection EPSG:3857 and "on the fly" transformation enabled. It was matching ...
1
vote
0answers
159 views

Creating a Raster of Road Distance to Point

I am using QGIS 2.6. This question is in two related parts: I'm trying to create a raster of travel time from one point to another point travelling via the road system. Each raster pixel will roughly ...
0
votes
0answers
17 views

How to draw coordinates QGIS print composer? [duplicate]

I am trying to add coordinates to a map, I fix all of the settings, but they don't show in the map... Do I need to do any previous work?
0
votes
0answers
133 views

QGIS raster symbology problem in 2.6

With the new 2.6 QGIS version I often have problems with raster colors. For some reason certain pixels do not display initially, but if I move the raster a little spatially they show up.
5
votes
3answers
3k views

QGIS 2.6.0 Minidump crash EVERY TIME I SAVE

Just got QGIS 2.6.0 running on Windows 7 service pack 1 64 bit. Project loads, edits, saves editing changes, adds removes, layers no problem. Only problem is saving the project. Do that and it's ...
2
votes
2answers
124 views

Using python to batch process lasclip - LAStools/QGIS

I am trying to use the python console to batch quite a few processes from lastools. I'm having trouble with the arguments to lasclip. clipped_las = processing.runalg('lidartools:lasclip', True, ...
2
votes
1answer
306 views

QGIS 2.6 Brighton: Problem with zoom

I seem to have a problem with the zooming levels in QGIS 2.6 Brighton. When I go to zoom in to a vector or raster layer, e.g. for digitizing purposes, the scale seems to be fixed at 1:2,256, I can't ...
1
vote
1answer
250 views

How to import multiple shapefiles without any dbf to a postgis database?

I have a polyline shapefile (.shp and .shx) without .dbf. I would like to import the shp into Postgis. In order to do that, I created the corresponding .dbf using the r code provided by mdsumner in ...
3
votes
3answers
482 views

Saving a QGIS project using the API loses mapcanvas (and other) XML nodes

I'm using the following python script to open a QGIS project, modify some things, and save it under a different name: from PyQt4.QtCore import QFileInfo from qgis.core import * def main(): ...
1
vote
1answer
364 views

Creating a mosaic with gdalwarp - How to deal with no data and overlap

I want to create a mosaic of satellite imagery in .tiff format. I want to create an actual mosaic, not a vrt, because afterwards I will cut the image in to tiles that make sense for my users. Gdal ...
2
votes
1answer
184 views

Intersection between polylines feature to polygon in QGIS

I would like to transform a line shapefile into polygons. However, the tool Vector>Geometry>Line to Polygon doesn'to work to me. What I would like to do is using the intersection between lines and ...
3
votes
1answer
175 views

How to get the length of each line segment in a line shape file in QGIS

Iam new to QGIS. I drew a line depicting a small length of road. But I drew it in segments and then atlast right clicked at the end point and gave id=1. I extratced the nodes, their geometry. But what ...
2
votes
1answer
391 views

How to add vertex to an existing polyline programatically?

I have a Polyline and would like to add new vertex to before start point or end point or at any part of the polyline using python in qgis. How can i do that?
1
vote
0answers
33 views

Avoiding intersections with QGIS Spline plugin (Version 2.0)

Has anyone gotten the QGIS 'avoid intersections' option to work when adding polygons via the Spline plugin? When checking the option and enable topological editing, I continue getting overlaps in my ...
1
vote
0answers
79 views

How i can have the same xMin,yMin for vector files in Qgis 2.4

i have a .shp file(polygon) in EPSG:2100 - GGRS87 / Greek Grid and an other .shp(points) in the same system(EPSG:2100 - GGRS87 ) but different xMin,yMin. The first has xMin,yMin 583309.00,4152885.94 ...
1
vote
1answer
1k views

Converting local Coordinates to lat/long Coordinates using QGIS?

I'm using QGIS to do some data analysis and visualization for my newspaper and I'm a basic/novice user at all this. I received some x,y coordinates from the City of Minneapolis that I can use to ...
4
votes
1answer
452 views

Digitizing contour lines from paper maps using QGIS?

Is it possible to give digitized altitude lines (from paper map) heights using QGIS?
2
votes
1answer
80 views

area elevation distribution with QGIS

I have a raster DEM and a polygon covering a part of it. I need an area-elevation distribution (i.e. how many m2 are in which elevation interval). 20m intervals will be fine. I cant figure it out.
2
votes
1answer
33 views

Percentage of a polygon at, or less than, a specific height (supplied by a raster)

I am using QGIS to process some LIDAR data. I need to be able to define the area of a pond with respect to its depth (i.e it is 100m^2 at 32mAOD and 500m^2 at 33mAOD). Is there a way of finding the ...
2
votes
0answers
78 views

QGIS returns “invalid layer” when adding a WMS layer

I want to add a WMS layer in my map. I select the server and obtain the list of layers that are published there. I select one of them (the problem is the same with all layers), but QGIS does not load ...
1
vote
1answer
85 views

How do I make my map use a set of coordinates

Right a little background. I've made a custom google map with the google map api which has a few functions that work well within it - one specifically is limiting the user on what they can view within ...
1
vote
0answers
54 views

How to merge DMAs using QGIS — Creating Custom Regions?

What I am trying to do might seem basic, but bear with me as I am just hacking my way through a lot of this space. What i am trying to do: I am trying to create a new .shp file of custom regions. ...
2
votes
1answer
218 views

QGIS print composer, DMS grid when SRC is not in decimal degrees

I have a QGIS project where the layers are in projected SRC, and when I go to the print composer to draw the grid, the units are in millons of meters, and I want them in decimal degrees. Is it ...
2
votes
1answer
142 views

J2000 to WGS84 in QGIS?

How to transform Earth-Centered Inertial J2000 CRS to WGS84 CRS in QGIS? I searched J2000 in spatialreference.org, however nothing found. I don't know the proj4 string of J2000. Any advice would be ...
2
votes
0answers
116 views

Menu actions in QGIS 2.6 feature attributes

I would like to ask about new menu 'actions' in feature attributes which appears in new QGIS 2.6. This menu shows 'actions', defined for the layer but I am wondering if it is possible to add some ...
0
votes
1answer
242 views

Apply an sld to a vector layer in OpenLayers

I'm trying to apply an sld style to a vector layer in Openlayers. I already took a look on google and here and I got a lot of informations, but still I don't manage to achieve the result I'm looking ...
2
votes
2answers
186 views

With QGIS Plugins/PluginBuilder, how to prevent 2nd instance of Plugin from starting

I am using QGIS 2.6.0, with PluginBuilder 2.0.3 [checking the version, I just noticed that the 2.1.0 update is available] I am writing a plugin; it installs and runs. While running, I am able to ...
3
votes
0answers
463 views

QGIS 2.6 Brighton - Graduated Symbols

I can't get graduated symbols to show in QGIS 2.6. This is what I have done. I have two fields of type integer, saved as a shape file which I have tried to import as a shape file and as a secondary ...
3
votes
1answer
211 views

Add button to custom standalone QGIS application

Im able to implement zoom in and zoom out functionality as described in the PyQGIS developer cookbook using a tool bar. I would like to have buttons that display above my map canvas layer and have the ...
3
votes
1answer
183 views

How to prevent users from removing QGIS layers?

I need to prevent users from removing layers. In my plugin code I use the following to achieve that: QgsMapLayerRegistry.instance().layersWillBeRemoved.connect(self.dontremovefunc) def ...
2
votes
2answers
161 views

Using QgsRasterCalculator

I'm trying to make a sum of n rasters and create a new one using QgsRasterClaculator, the problem is, every time the code reaches processCalculation, it makes QGis close and create a dump file. I ...
1
vote
1answer
77 views

Compute nearest points to other points using GRASS

I have a layer of address points and a layer of polling stations. My task is to determine the three closest polling stations to each address on the street network. I think that the answer is in ...
3
votes
1answer
484 views

PROJ.4 - General Parameters: +no_defs

within a QGIS-course I would like to tell a bit about the proj.4 parameters. However, I´m not sure about the "+no_defs" parameter. The proj.4 website (https://trac.osgeo.org/proj/wiki/GenParms) ...
3
votes
1answer
79 views

Incorrect placement of a MrSid file in QGIS

I have a map saved as MrSid file which when loaded in QGIS displays as a southern hemisphere location despite being in the UK. When looking at the .sdw file the northing is positive but in QGIS it ...
2
votes
0answers
68 views

Is there a way to change floating toolbar orientation?

Is there a way, within QGIS 2.*, to stop the interface from trying to snap in floating toolbars (as attached pic)? I want to maximise canvas space, but the interface keeps on wanting to grab my ...
2
votes
0answers
234 views

How to create dynamic maps based on updated attributes in SHP file

I am novice GIS'er. I can create maps and do basic transformation of the SHP file using QGIS. I also succesfully applied formatting based on attributes. I am able to add new attributes to SHP file in ...
2
votes
2answers
256 views

Is there an algorithm for transforming from CGCS2000 to WGS84?

Is there an algorithm that supports transforming from CGCS2000 coordinate to WGS84 coordinate? CGCS2000 is China Geodetic Coordinate System 2000. Any advice would be thankful!
1
vote
2answers
48 views

Reduce squarish effect on group of polygon

I am trying to represent the average speed of some ship in the north of Mediterranean sea. I am interested in aggregate the speed information by zone. The raw data I am working with are .shp with ...
3
votes
0answers
219 views

QGIS installation failed - requires matplotlib which has been installed by Anaconda

Is there any way to specify python environment variable to solve this? When I tried to install QGIS on my machine - mac OS 10.9 and Anaconda has installed numpy, scipy, and matplotlib, I got the error ...
0
votes
0answers
179 views

Extract Aerial Imagery using QGIS

I need to create city-wide (Warsaw in this case) aerial based map, pretty detailed (clearly visible buildings and possibly 1-pixel-sized cars. So far the only way I found is: Using this method: ...
0
votes
0answers
170 views

How to create a map in Pulkovo 1942 with grid?

I have a problem with coordinates when I change projection. With WGS 84 it's fine, I have normal, geographic coordinates. But when I'm changing to Pulkovo 1942 (I need a map of Poland), coordinates ...
0
votes
2answers
73 views

Error with layer.pendingAllAttributesList

While coding to obtain individual layers' attributes (field) list, I am stymied by the code. I can identify a specific layer: MyLayer = QgsMapLayerRegistry.instance().mapLayersByName("TestPoint") ...
1
vote
1answer
26 views

How do I ensure polygons are properly displayed when using 'on the fly' CRS transformations in QGIS 2.6?

QuantumGIS 2.6.0 (Windows 7 64-bit) I have created a PostgreSQL POLYGON as WGS84 (CRS 4326). The polygon is a series of points around (but not actually on) the edge of the map. This is a rectangle ...
1
vote
2answers
373 views

QGIS Python Script - Routing along Waypoints [closed]

I used Anita Graser's script point_layer_to_route.py which worked like a charm until I updated to 2.6. With QGIS 2.6 I always get objects without any features. Can anybody tell me if he/she had the ...
2
votes
2answers
121 views

fit a wrap column in the print composer QGIS 2.4

i have an attribute table in the map composer, and the field i want to see is quite long...so i wrap it. but the field width is not fitting this new length. how can i do that. is qgis prepared to do ...
0
votes
1answer
84 views

Is there a QGIS plugin that can transform tabular data to graph?

I have a CSV file with water level measurments in a well, taken once a year for 40 years. Is there a way to show this data as a graph (x axis being the date and y axis the water level) in QGIS?
3
votes
1answer
86 views

How to insert some holes in a polygon?

I have a problem with QGIS digitizing advanced tool plugin. I have a landcover-like shapefile. I have to perform some corrections on it, and I have to cut or split some polygons. I want to insert some ...
0
votes
1answer
362 views

How do I use a filter on an uncached WFS layer in QGIS?

I am trying to create a filter to show only specific features based on an attribute query within a WFS using QGIS. This works fine when using the standard WFS loader and creating a filter (based on ...
1
vote
1answer
87 views

How can I avoid displacements in exportet JPGS from QGIS 2.2? [duplicate]

I observed a small but annoying problem for a long time now. I have to design maps/plans of survey areas for work including maps where a satellite image is printed under a vector-layer showing the ...