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

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2
votes
2answers
38 views

How can I import shapefile in python?

How can I import a shapefile in python? from PyQt4.QtCore import QSettings, QTranslator, qVersion, QCoreApplication from PyQt4.QtGui import QAction, QIcon, QFileDialog # Initialize Qt resources from ...
2
votes
1answer
17 views

How to apply a radial fill to a voronoi polygon centred on its original home point in QGIS?

I'm working with a point layer (airports from OpenFlights), and I want to create a map of distance to the nearest airport. I thought I might be able to do this by using radial fill on the voronoi ...
1
vote
2answers
54 views

How do I make equidistant circles covering the whole globe in QGIS?

What's the simplest way to make equidistant circles in PostGIS/QGIS? (my software versions are Postgres 9.3, PostGIS is 2.1, QGIS 2.10) I tried this in PostGIS, but the circles that come near or ...
5
votes
4answers
1k 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 ...
0
votes
0answers
5 views

Using Lastile in Qgis

I want to tile one large las tile into few minor. But i just cant get it done. My original LAS file have around 30mil points and i want to get 5 smaller LAS files with 5mil points in it. What is ...
6
votes
3answers
141 views
+50

Creating disease risk map in QGis

I would like to create a risk map using RFE Data and Tiffs but now I realised that I actually have no idea how. I have dowloaded .Tiff(Region), .hdr and .bil(Rainfall/RFE) files from the USGS page, ...
0
votes
1answer
47 views

Sorting points based on Northing and Easting

I have around 1320 point/centroid features in a shapefile for my research plots. Each point/centroid has X and Y coordinate associated with them which were calculated using Field Calculator > Geometry ...
23
votes
7answers
24k views

Removing small spaces (slivers) between polygons?

I have a set of polygons representing administrative districts. The districts were digitized by hand, and there are small spaces (slivers) between polygons where the polygons should be touching. How ...
0
votes
0answers
19 views

Displaying heatmap with large number of dense points of interest in QGIS?

I am currently trying to make heatmaps of bird observations in an area. I have had a lot of success making the actual heatmaps for most birds, except the ones that are extremely abundant. I use the ...
1
vote
1answer
32 views

Can't get my QGIS external map to display on Ubuntu trusty: QObject::connect: Cannot connect (null) error

I've been following along the examples from the book "Building Mapping Applications with QGIS and for the life of me I can't figure out why my shape files aren't loading and displaying in the app ...
0
votes
1answer
111 views

GeoJson and D3.js multipolygon

I have this geometric shape file, so no map of a city. I store the two Shapefiles in a GIS database as a geometric form. Now, I want to visualize the geojson data. I created the GeoJson data ...
2
votes
1answer
46 views

How to load a style from POSTGIS in PyQt

The thing is that I have four styles I have created in QGIS through the GUI and saved into a postgresql database. I can see them in the table named layer_styles I have seen similar questions asking ...
2
votes
1answer
12 views

OTF reprojection and reprojecting layer not working in QGIS

more troubles in QGIS. I georeferenced this raster in Corrego Alegre UTM23S and loaded up, so project CRS automatically changed to that. So far so good. I need it to be however in WGS84 UTM 23S. None ...
3
votes
2answers
57 views

How to create a dashed polygon border in C++?

In my maps I have a symbol, his type is polygon, I want to change the line style of the border, actually is solid , I had to put it in dash Is there a simple way to change it ? i think to the ...
4
votes
1answer
44 views

How do I count the number of vector lines that pass though a given raster cell?

I am working on a project (currently in GRASS7 though I'm not against exporting to Arc or R or other software if necessary) where I am generating thousands of shortest cost paths (using the r.walk and ...
3
votes
2answers
437 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 ...
5
votes
2answers
101 views

How to run qgis scripts in parallel across remote server(s)

I have a stand alone python script using qgis that I wrote with the help of the SE question here The script takes three arguments being; an input file path, an output file path, and another input ...
3
votes
2answers
45 views

How can I create a QGIS plugin that needs an external Python library?

I’m trying to enhance QGIS's Profiletool plugin by adding DXF export functionnality. For this, I need to to import dxfwrite library. As it's installed on my computer, i added the following lines to ...
0
votes
2answers
149 views

Displaying polylines in different color / Color gradient

Though i am using QGIS, yet I am not confined by tool (can use an entirely different tool or a plugin for QGIS) usage.. Only aim is to get the following: I am reading various shapefiles in QGIS and I ...
0
votes
0answers
26 views

Qgis network analysis why find vertex return always -1

I'm trying to compute the shortest path between points using the QGIS networkanalysis library. But the graph.findVertex always return -1. Basically what I'm trying to do is : 1/ Given a set of ...
0
votes
1answer
10 views

Loop to check multiple polygons overlap in r

I have a set of polygons (available here: http://ulozto.cz/x39ELbFt/polygons-zip) created in QGis and processed in R. I would like to know if they are overlapping or not, and if yes, where is the ...
1
vote
1answer
155 views

Trying to set NAD 1983 EPSG 102631 in QGIS

I was able to find the right coordinate system online NAD 1983 Alaska But now I don't know what to do. I can't find the coordinate system on QGIS. When I choose the one I think is correct it warps ...
3
votes
0answers
47 views

How to access a deleted features attributes (before committing)

I have a signal setup for a feature deletion event on a layer: self.layer.featureDeleted.connect(self.feature_deleted) When I try and grab an attribute from the deleted feature on the slot, a ...
1
vote
1answer
40 views

My QGIS plugin shows GUI but not Works. How to get Error log?

I am new to PyQgis. I made a simple calculator with PyQt4, now I am trying to run it under QGIS. I connected calculator as plugin, and tested it, its GUI works without error but it does not calculates ...
1
vote
1answer
70 views

How to get the signal when the color changes in pyQGIS?

I would like to have the signal when the color of a vector layer is changed by the user. In the doc, there is a signal that seems to fit ...
1
vote
1answer
20 views

How to scale SVG symbols which are not label background on zoom level in QGIS

I need to scale the SVG symbols on zoom level. @Underdarks answer in the posted question did not help me thus I can't set the SVG symbols as label background for I have labels which should not be ...
0
votes
0answers
14 views

Prevent Overlapping Features in QGIS from Being Faded

I have multiple layers in QGIS that I've set as transparent so I can see their respective features. However, I would like one layer (showing proportionally sized points) to NOT fade when it overlaps ...
6
votes
0answers
185 views
+50

How can I create a form so the user has to be authenticated to access a project?

I have a login form in QGIS and when it is loaded, python gives me an error for, apparently, not recognizing the findchild part. This is due to the fact that the form isn't loaded before the script is ...
5
votes
0answers
221 views

How to create a chart of elevation using points?

I am using shapefiles with basic information including the x-, y- and z-coordinates. I want to see how the objects (in this case points, which are finds from an excavation) are scattered along the ...
1
vote
2answers
48 views

Polygons in one layer have different attributes

Is it possible in PyQGIS to have in one layer more polygons and some would have one set of attributes and another different? E.g. Polygon_1(name, size, average_age), Polygon_2(name, size, ...
0
votes
1answer
16 views

Normalized icon for BOYLAT

I try to find normalized icons to use for the BOYLAT ( lateral buoy ) I find description, but for the boylat it seems that different shape to show different buoy link for the description ...
0
votes
0answers
11 views

How can I extract the latitude and longitude from a s57 File [duplicate]

I had to extract the longitude and latitude from a s57 file, in order to superpose a satelite view from the same point. These coordinate will allow me to get the exact position on google map by ...
2
votes
0answers
30 views

How do you merge overlapping .asc files in QGIS with topography and bathymetry?

Firstly, apologies for any incorrect terminology - this is my first time trying to manipulate GIS data. I have two files. The first is higher resolution (SRTM) topography data for a region of islands ...
70
votes
4answers
46k views

File Geodatabase (*.gdb) support in QGIS?

Following questions: Open Source Tool capable of reading Esri File Geodatabase (.gdb)? How to access file geodatabase in Qgis? How to get FGDB support in GDAL 1.9 without compiling? I have spent ...
6
votes
6answers
255 views

Is there a quick way to clear all attributes from a layer but leave the polygons in place?

I have a Shapefile layer in QGIS 2.6 with several polygons, each of which has data in over 100 fields. I need to create a new layer with all the same polygons, but with all their data fields blank ...
1
vote
0answers
15 views

What solutions to use QGIS as insert tool for a Postgres relationnal database?

I have a Postgres/PostGIS relational database and I would like to use QGIS as an interface for inserting data. The thing is that my database is quite complex and I need my tool to handle the following ...
0
votes
0answers
14 views

QGIS measure growth in special directions

I want to measure the growth of different areas in special directions. The same as in this article of M.S.Moeller on page 5 (Figure 5 and 6). But I don't know how to build such a Wind Rose in Qgis. Do ...
2
votes
1answer
29 views

How to calculate the 3D length of line segment in QGIS?

I've been looking through all of the GRASS commands in the QGIS 2.10 processing toolbox and it seems like one of these must be able to do this but I haven't found one yet. There is 'v.sample' which ...
1
vote
1answer
14 views

automated selection by attributes and location within another Layer

I have two Polygon Layers. Layer A are Districts of a City and Layer B are Blocks of a City. Currently i'm working with QGIS 2.6.1 and i don't have access to any other GIS. What i'm trying to do is: ...
1
vote
2answers
229 views

How to create a polygon feature using Python?

I'm making a plugin for Quantum GIS in python. I have a polygon layer and want to create a new feature. So far, I have this because I need a polygon geometry to add the feature: surface = ...
1
vote
2answers
84 views

Why is SAGA from the Processing Plugin not recognised?

Similar to this post: SAGA algorithms don't work in QGIS 2.8 except the fact that SAGA does not appear at all in the Processing Toolbox: As a check, I used the Python Console with the following ...
2
votes
3answers
580 views

Draw line between points from multiple datasets

I have 2 point datasets and want a tool or script to draw a line between all points in one dataset to all the points in the 2nd dataset. Is it possible? I have tried ESRI "Point Distance" and ...
2
votes
3answers
2k views

Convert Shapefiles to GeoJSON?

I'm trying to convert Shapefiles from the State of Texas Senate Districts website into a GeoJSON file for use with Google Maps API. I'm using QGIS to facilitate but I can't get the ...
0
votes
0answers
23 views

Merge layers (SAGA) ERROR

with QGIS 2.10 it is not possible to merge vector layers with the "Processing-Saga" tool (merge layers). The following error log comes up: Algorithmus Merge layers startet... shapes_tools "Merge ...
1
vote
1answer
294 views

How to generate random points with minimum distances between points in multiple polygons

I am looking to create random points for a random stratified survey. There are three different categories being surveyed; for each, I have a single shapefile, each containing a number of polygons. I ...
2
votes
1answer
25 views

Calculating distances across land only

I am trying to do point to point distances in QGIS but I have points to point distances that are being calculated across oceans. Given people don't generally fly around cities does anyone know a way ...
1
vote
0answers
26 views

Why do pixel (cell) values change for 32 real NDVI values when taking from Multispec to QGIS?

Landsat 5 values change from normal NDVI -1 to 1 when created in Multispec as a 32 bit signed data image. When adding the raster layer in QGIS, the value range changed to 0-255. How does one ...
0
votes
3answers
5k views

Why won't QGIS recognize my GPS?

Garmin BaseCamp recognizes and receives data from my GPSmap 60CSx, but QGIS GPS Tools plugin does not. Am I missing a step? I want to be able to transfer data both directions. MacOS 10.6.8 QGIS ...
3
votes
1answer
258 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 ...
1
vote
0answers
60 views

Unable to stylize as pseudocolor render type

In a raster layer's Style Properties, I can choose pseudocolor render type, and choose a color ramp and classify the raster. However, when I click the 'Apply' button, or click 'OK', the ...