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

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-3
votes
0answers
31 views

how to write first program in QGIS [closed]

I installed QGIS but I cant understand how to write and execute a simple hello world program. I am C# programmer and very beginner in QGIS.
-4
votes
0answers
23 views

QGIS 2.14.1 Point density graduated feature [closed]

I am working on QGIS 2.14.1. I want to know how to use the graduated feature to show point density of herbivores into the grids. I want to show different shades for different densities within the ...
1
vote
0answers
5 views

Mapping shapefile attributes to raw data [duplicate]

I have raw address data stored in a sql server database (2012) which comprises address, city/suburb, state and generally country (Australia). I would like to take this address data and following ...
2
votes
1answer
60 views

How do you create a buffer for a specific feature in QGIS?

Fairly competent ArcGIS user here, very new to QGIS. What I am trying to do is create a one-mile buffer around the highlighted parcel in QGIS 2.14 (from a .shp). Seemed straightforward enough: ...
3
votes
1answer
33 views

Get the full list of commons

In QGIS I've loaded the shape file "province" in which attribute table contains 242 fields (the municipalities of this province) and also two other files downloaded from openstreetmap about hotels ...
4
votes
0answers
48 views

Issues updating field values programmatically for particular field data type on 64bit Windows computer using QGIS 2.8.7

I have an issue with a plugin for QGIS 2.8 I'm developing when using it on a Windows 64bit machine (as opposed to 32bit). I am trying to update values in a particular field in my plugin, and the ...
3
votes
0answers
32 views

Translating ArcGIS field calculator python expressions in to QGIS field calculator python expression?

I'm transitioning to QGIS from ArcGIS. I'm having trouble getting my python field calculator expressions to work in the QGIS advanced python field calculator. Here is a screenshot of the working ...
2
votes
2answers
46 views

Convert a vector into a csv file [duplicate]

Is it possible to use QGIS to convert a vector that contains points/polygons into a csv file and, if yes, in which way?
3
votes
2answers
74 views

How to calculate the relative share of an area of a circle that has a slope >15% in Germany

I need to calculate the share of buildable land for the 15 major german cities within a 50 kilometer radius of the city center. Part 1 of the definition buildable is that the area must have a slope ...
1
vote
1answer
29 views

Extract results from zonal statistics

I am trying to calculate mean slope in given polygons. I first interpolate my (x,y,z) data to create a raster file and use the terrain analysis tool to calculate slope. Then I use the zonal ...
0
votes
0answers
23 views

How to use the “geometry generator” to intersect geometries with an entire layer in QGIS?

In the "geometry generator" style in QGIS, it's possible to define an intersection for a specific geometry of an other layer like this: intersection($geometry, geometry(get_feature( ...
1
vote
1answer
47 views

Why does joining all layers in a group not work?

I am attempting to re-join all layers within a group to another layer ("Main.shp") outside of this group. The idea is for users to change values in one of the group's layers. As these layers are ...
1
vote
1answer
23 views

Create lines between two points, given an ID

I have a spatialite point table (p1) with an additonal column (pid) that relates each point to a point in another point table (p0) in the same database. I want to create a line between every pair of ...
1
vote
1answer
41 views

QGIS 2.14 save pdf with google maps

I have an shp file in CRS 2100. I use the open layers plugin and inserted goggle satellite as background. It changes the project's CRS into 3857(OTF). So, in the composer manager, when I try to save ...
3
votes
1answer
31 views

displaying attribute table on top

I would like to pin (fix) the opened attribute table to the QGIS window or display the table on top. The attribute table is opening as another window (and it is possible to open the same attribute ...
1
vote
1answer
37 views

How to design a flood with water elevation on a specific point?

Actually I have to know the flooding area caused by a rise of the water level due to the implementation of a dam. So I would like to know if there is an extension or any tool in QGIS or GRASS which ...
2
votes
2answers
42 views

Sum line lengths by category

Is there any chance to calculate line lengths by category. To be precise, I have 4 road categories (state, county, local and uncategorized) and want to calculate them all within one poligone. So ...
2
votes
1answer
43 views

QGIS: intersect on a single shape file

I am using QGIS version 2.14.1 (Essen). I'm trying to do some spatial analysis, including an intersect between the same shape file. Basically I have a shape file with the geometries of all the events ...
3
votes
0answers
22 views

Create an optimised path between nodes avoiding polygons entities

I have nodes as a shapefile representing seaports. I have the linear cost of shipping for every pair of seaport (specific shipping cost to go from one node to another node). I want to find a way to ...
1
vote
0answers
30 views

Finding point on line closest to other point: unexpected results [closed]

I'm basically trying to do the same thing as outlined here: Finding the point closest to a point on a near feature However, the results I'm getting with the queries suggested in the accepted answer ...
1
vote
0answers
18 views

How to write postgres source in virtual layer in Qgis 2.1x

In Qgis 2.14, I am trying to create a connection with my postgres database using virtual layer. But in the virtual layer window, how should I write the parameters in source field ? I can't find any ...
4
votes
1answer
58 views

Is it possible to create a round map frame in QGIS Map Composer to create circumpolar maps?

Does anybody know if it's possible to create a round map frame in QGIS Map Composer to create circumpolar maps?
-1
votes
2answers
44 views

Merge layers with different geometry

I need to merge two different layers but they don't have the same geometry, in particular one contains points and one is a polygon (province). Is it possible to do so by converting them to the same ...
1
vote
1answer
36 views

Two inner polygons touching and covered by two different outer polygons

I need to create a topology where 1 and 2 touch but don't overlap, a and b touch but don't overlap, and 1 covers a and 2 covers b. Is it possible to achieve this? I've tried various snapping ...
3
votes
1answer
49 views

How can I work with time in QGIS

I would like to make a map displaying how several building uses have changed during the last decades. For example, this building was built in the year 1483 as a monastery, in 1880 it turned into a ...
2
votes
1answer
24 views

Raster rotation on QGIS

How can I rotate a raster layer (global land-mass) to make the 180 deg longitude the center of the map (using QGIS)? 'rotate' function in R is simple but not accurate. Raster has 'longlat' projection ...
1
vote
2answers
39 views

QGISimported CSV points are not visble

I am trying to import CSV file and get no reported errors but there are no points visible. If I click on "zoom to extent" nothing happens (even if I move away from the location of the points before ...
-1
votes
0answers
24 views

Indoor path finding

I am working on an interior geolocation project on Android with Indoor Atlas SDK, and I needed a way to map precise points on the map to LatLong. After trying to code an algorithm that converted x,y ...
4
votes
2answers
53 views

What's the correct syntax to use Processing gdalogr:merge from python?

I am using gdalogr:mergein Python console in order to merge to rasters (.tif) But I don't really understand the first parameter, where I have to put two variables. I get the following error: ...
2
votes
3answers
122 views

How to count classified points in polygons?

is there a way to merge the attribute table of a csv file into a the attribute table of a vector? Join is not the answer for me because in this way the plugin GroupStats that you suggested me to use ...
2
votes
0answers
27 views

QGIS Function Editor/ Python question

I'm currently using the layer_property(layerName,'source') to produce a list of copyright statements for the Print Composer by putting that in an if() statement. However, that isn't very flexible as ...
5
votes
1answer
67 views

QGIS clip vector layer to current map extent

I wonder if there is a way to simply clip a vector layer in QGIS (2.14.1) to the current map extent. Clipping algorithm needs another 'clipper' vector layer as input and 'save as...' saves a vector ...
3
votes
0answers
18 views

QGIS create raster from csv and find raster index [duplicate]

I have a csv with about 2 Mio. entries with X and Y coordinates WGS84 and many attributes. The X and Y coordinate are the south west coordinate of 100 meter by 100 meter grid over a country. But the ...
4
votes
2answers
48 views

How to get layers in x number of subgroups?

I have a project which has dozens of groups and subgroups. E.g.: Main_Group > Sub_Group_1 > Sub_Group_1A > Layer_1A > Layer_2A How can I access ...
1
vote
0answers
27 views

Eclipse PyDev has quit recognizing QGIS objects

I followed the instructions for setting up Eclipse with PyDev to start creating QGIS plug ins found here: http://docs.qgis.org/testing/en/docs/pyqgis_developer_cookbook/ide_debugging.html after doing ...
2
votes
0answers
47 views

Classification and measurement of feature basing on scan [closed]

It`s not entirely a GIS question, however maybe somebody can help. I need to automatically classify and then measure area of certain elements on image. That image is a scan of a thin wood slice and ...
0
votes
1answer
17 views

QGIS algorithm parameter: <ParameterString> [duplicate]

I have been working with the algorithm gdalogr:warpreprojectand have failed several times in the parameter in the title. Now, the problem is solved. It was about the EXTRA parameter. I read 3 books, ...
2
votes
0answers
48 views

Deployment of optical fiber QGIS Python

The subject that I’m working on is the deployment of optical fiber . I have a shapefile which represents a country containing homes. And I have another shapefile representing an infrastructure plan of ...
1
vote
0answers
13 views

Median and Mode estimations in the QGIS Modeler?

I would like to know if there is anyway in which I can combine the available tools in QGIS in the Modeler to estimate median and mode values from a raster (DEM) using polygons. I know the zonal ...
1
vote
1answer
26 views

QGIS Script Editor to get operations between raster and float number

I am looking for developing python codes mainly for working with raster data, in particular satellite imagery from Landsat. I need to write a script (into the QGIS Script Editor) to make operations ...
4
votes
0answers
26 views

Automatically style raster using unique values in QGIS?

In ArcMap, it is possible to automatically calculate the unique values for a raster and then apply a different style to each unique value (see 1st image). However, in QGIS, I have to manually add ...
4
votes
2answers
114 views

Double classification for symbols in QGIS

I am using QGIS version 2.14.1 (Essen). I have symbols that I have classified according to certain value from one of the columns in my shapefile. Furthermore, I was wondering if it is possible to do ...
9
votes
3answers
142 views

How to refresh the attribute table of a layer after editing the table in the DB-Manager?

Is there any way to refresh the attribute table of a layer after editing the table (e.g. add a column) in the DB-Manager?
4
votes
2answers
128 views
+100

How to render layer into png in a standalone application?

I would like to use standalone appliction to apply .qml style to a layer and use QgsMapRenderer() to save it as image on a hard disk. The are a lot of questions like mine at this site and it seems ...
3
votes
1answer
44 views

Topographic Position Index unexpected result in QGIS

I am using Windows 7 enterprise and QGIS version 2.12.2 Lyon. Have found an unexpected result when I use QGIS to generate a topographic position index (TPI) raster from a 30m by 30m DEM. I find a ...
3
votes
2answers
57 views

Label and symbol with condition in layer properties under style tab

I have forest areas. I want to put tree.svg with condition. Layer properties-> style-> background -> shape ->svg Something like this: if (myfield<1300 , then show, ...
0
votes
2answers
34 views

Trouble getting shapely to run

I downloaded the GDAL complete Framework von Kyngchaos which also includes the GEOS Framework and shapely for python. I can import shapely without a problem, but when I try to perform some "geo ...
2
votes
1answer
52 views

Coordinates calculation using QGIS

I am quite new to GIS software. I use QGIS. I have a question that might be trivial. I would like to derive the coordinates (Y and X) for an area. Just to make an example: I have two regions A and B. ...
4
votes
1answer
109 views

Cannot locate GRASS plugin in QGIS 2.14.1 on Linux

I am trying to load the GRASS plugin in QGIS but it is not shown in the plugin manager (no matter if I turn on experimental and deprecated plugins). Under processing / options / providers GRASS GIS 7 ...
2
votes
1answer
27 views

Polygon rendering issue in map composer, QGIS 2.8

Since a picture is worth a thousand words, let's go straight to the point. This is what I get in QGIS main window (and what I'd like to get in QGIS' map composer): And this is what I actually get ...