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

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7 views

access the encrypted table in qgis

I have a vector layer in qgis connected to PostgreSQL database table. Suppose I encrypt the table column using pgp_sysm_encrypt or some other encryption in PostgreSQL Is there any way i can say ...
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0answers
3 views

How to change programmatically the value of attribute in one of several feature in a vectorLayer

I have a vectorlayer that contains a lot of feature, I know that each feature has an unique Id Each of them has some propertie like coordinateX, coordinateY, color, name With a QTimer, each 2 sec I ...
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0answers
6 views

Building error on changegeometryvalues

I am working with c++/QT and c++api gqis 2.8.2 I want to change the geometry of a feature, I have this code : QgsVectorLayer * lLayer = mMapLayer.value(TRACKS); QgsVectorDataProvider * ...
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0answers
14 views

Is QGIS aspect analysis description mistaken?

I've been checking the Aspect analysis tool and several sources indicate that aspect is measured from 0 to 360, starting North and going counter-clockwise. Nevertheless, I've been testing it on ...
1
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1answer
11 views

Trying to create colour co-ordinated values on a map from data from a csv. file

I have a list of values for some data recorded via Magnetic susceptibility, I have these in a shapefile and want to try creating a colour map out of the values. The values that I'm using relate to, ...
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0answers
7 views

fTool -Line to Polygon does not work

I am working new with QGIS (Version 2.8.2 / Window 8.2) and try to make Polygon from Line (see example picture 1) with the fTool LineToPolygon, but it doesn't work (see picture 2). I work with ...
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0answers
12 views

how to rotate a symbol

I am working in c++/python/QT 4.5 with the api qgis 2.8.2 My application receive data from a communication port that indicate the change of position of an object diplayed on the map and represented ...
1
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0answers
15 views

Remove inner rings from QgsGeometry polygon in QGIS Python

I am a QGIS python user. I want to iterate over rings of polygon to remove holes in polygon, so: I need to iterate over rings in QgsGeometry polygon I need to detect main ring of polygon I need to ...
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0answers
12 views

How to change the value tof the use tag in a svg file

I am working in C++/QT4.5 with the qgis c++ api 2.8.2 I have a svg file that contains different form tag by Id When i want the first form i place the id name in the use xlink:href="#formname" .... ...
2
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1answer
23 views

How to center a user-defined CRS on an area of interest?

My study extent in central Iran straddles two UTM zones (39 and 40): I would like to create a user-defined CRS in Transverse Mercator projection with central meridian inside this area. Through ...
1
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0answers
15 views

Toggling selected feature when using Node Tool of QGIS?

Does anyone know of a way, when using the Node tool in QGIS to edit a polygon, to choose or toggle which feature (within the same layer) is being selected if they share a boundary? It seems to just ...
1
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1answer
25 views

Selecting features within bounding box using QGIS?

What is the best way within QGIS to select all of the features within a rectangular bounding box? Is it necessary to create a separate layer with the box, then to use the intersection tool within ...
1
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0answers
22 views

Communicate relation between two table

At this time, I'm able to create a relation (1:M) between two table or geometries. After, I user Identify tool to exploit the relation. It is only possible to use this feature when your Identify tool ...
1
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0answers
20 views

Projected CRS interfering with Spatial Analyses?

I have come across a problem I am very puzzled about. I am working with two polygon shape files, one of which is a buffer around the other, and a point shape file in a project set to EPSG:54016. All ...
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0answers
15 views

Difference between adding spatial layer from MSSQL through “browser” and “add MSSQL table”

So I am trying to pinpoint the difference of adding layers from MSSQL Database that contains spatial layers like geography and geometry. I have noticed that when adding from the browser it retains it ...
1
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0answers
7 views

Change Volumes when saving outputs?

Im sure there is a simple answer to this but its eluding me. When saving outputs/QGIS projects the file navigator interface opens up and I can go through my files until I find the place I want to save ...
2
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0answers
23 views

How to display charts next to features in the map?

This question is meant to be primarily on QGIS software but all other software solutions are welcome as far as it is possible to achieve it as easy as possible, preferably out of the box. Though the ...
1
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0answers
25 views

Make a new shapefile from parts of two shapefiles

I have tried all day to connect two shapefiles and crop a part of them and save it in a new shapefile. In the image see two shapefiles and inside of the square is the part which I want to export in a ...
1
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1answer
39 views

Python script to copy first row of certain attributes and paste in the newly digitised rows the copied features

Starting from this question, I need a script to be insterted in the processing graphical modeler that can copy some attributes from the first digitised row in all the newly digitised lines of a ...
2
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2answers
30 views

Store in a python list the attribute table of a vector in QGIS

I'm stuck with a very simple issue.. I've loaded in QGIS (through the py console) a csv layer (no geometry) made of 4 fields and 3 rows: #load the csv layer = QgsVectorLayer("path/to/the/csv", ...
0
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1answer
40 views

How to remove points in QGIS?

I have way points of my field work, but some of points I saved are not related to my project. How can i remove them in QGIS?
0
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1answer
51 views

Is there something like a fast access for QGIS?

When I need QGIS only to check up something, opening the QGIS application takes way to long (on my computer: 5 minutes from double cklick on the the project until ready). I tried QGISCloud which ...
2
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0answers
19 views

SVG symbols are not available on other computers

I created some layers with SVG symbols. Those symbols are saved on the server, as it is not possible to store it in the database (postgis). Every computer can access to the server. But if I open the ...
2
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2answers
43 views

How to find the irregular polygons in qgis using python

I have a vector shape file and i want to find the irregular polygons. What are the parameters to be considered to check the iregularity of the polygon features? Calculating the perimeter and extent ...
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0answers
13 views

Geofence and GPS-Tracking in QGIS

What is the easiest possibility to create a geofence and to track if subjects cross the fence? I assume the fence is a simple polygon vector? What do I need for the cars? GPS data set? GPS layer? ...
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0answers
17 views

ORACLE Metadata Table used by QGIS?

When connecting to ORACLE Spatial with QGIS, QGIS Needs a metadata table about all available Geomtry columns in the database. If not provided, QGIS scans all tables with geometry columns wich can ...
3
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5answers
62 views

Is there any simple integration for counting points in polygon using python qgis?

Is there any simple integration for calculating count of points in polygon using QGIS-Python integration? In other words, are there any pre-defined functions for points in polygon of QGIS using ...
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0answers
9 views

measuring a distance on QGIS 2.2. in meters not degrees [duplicate]

Im using QGIS 2.2.0 and when I want to measure the distance on a map, the units are in degrees instead of meters. I have tried this : Right click on layer -> "Save as..." -> CRS: Selected CRS (WGS84) ...
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1answer
31 views

Can we count the points in polygon using pyqgis code? [duplicate]

Does anyone know how to calculate the point in polygon from the given points and the buffer output using python qgis. I have every thing loading the data and retrieving the output. But now I want to ...
2
votes
1answer
22 views

from tiff file extract values with QGIS

I have download a tiff file with elevation from http://srtm.csi.cgiar.org/SELECTION/inputCoord.asp and i try to export in file text or excel the cordinates and the elevation and i dont know how to ...
5
votes
2answers
76 views

QGIS Filtering Multiple Values using Query Builder

I am a complete beginner in QGIS, so I'm sorry if I don't use the right terminology. In the "Query Builder" I can currently filter on value from the "Values List", but I'd like to be able to filter ...
2
votes
1answer
27 views

GRASS plugin for QGIS2.10 missing [duplicate]

I have installed installed qgis2.10 from source on Centos6.6 however the issue i'm facing is that i am missing the grass plugin form the gui. I have checked the plugin manager, its not listed there. ...
1
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1answer
33 views

Close dialog when algorithm is finished (QGIS plugin)

I've read many threads on this but I'm not able to figure out the solution (I'm a beginner to the plugin creation...). What I what to do is to close the dialog window when the algorithm has finished ...
4
votes
2answers
78 views

How can I remove the gap between two polygon boundaries in QGIS?

I have a couple of messy polygon boundaries (example data) that should share a boundary but don't: I've had a look at some suggested tools for a similar issue using ArcGIS in a separate question ...
3
votes
1answer
52 views

Convert shp 2 sqlite with correct character encoding

I want to convert Shape data with the QGIS browser in the SQLite database . Unfortunately, the umlauts then appear with a mark (see screen shot ) . I do not want to change the UTF-8 encoding for each ...
1
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2answers
65 views

PDF map with selectable layers

I need to make a map with selectable layers. I am using ArcGis and so far I am able to create a map that has some selectable layers and most labels are selectable. The PDF looks like below: But I ...
2
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1answer
25 views

Rasterization of point vector in QGis: how to align the resulting raster to an existing one?

I have a point shapefile, with no associated .prj file, that I have to rasterize. Each point should be transformed into a pixel of 30x30 size aligned to the pixels of a Landsat image (the point file ...
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0answers
14 views

Space points out a minimum distance along a line

I have just snapped thousands of points to the polylines they share attribution with but a lot of the locations overlap slightly. I would like to create a minimum distance between points. I DO NOT ...
0
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1answer
16 views

Why does Spatialite layer prompt for CRS if SRID was not explicitly defined in Layer Options?

In QGIS, if I Save As... a SpatiaLite file and don't enter an SRID in Layer Options, I will be prompted for a CRS upon opening the file. Yet GDAL documentation says that this option is only for ...
1
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1answer
21 views

Is the undo functionality possible in QGIS while creating a line feature?

I have noticed that when creating a new line feature in QGIS, control+z does not seem to be possible. When you insert a vertice of this line in a slightly wrong place, you cannot undo your actions ...
2
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0answers
59 views

Can we create buffer analysis using python in qgis?

Can we create a buffer of distance 0.004 using python in qgis. I tried this link, but it isn't working for python in qgis 2.10.1-Pisa. The above is the diagram of buffer I am asking. It's located ...
1
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2answers
55 views

How do I generate an image of each polygon in a shape file? [on hold]

I have shapefiles containing areas (states, counties, bodies of water, etc.) and need to generate an image (png / jpg) of each area. How can I do this? In my mind, the manual workflow would be: ...
2
votes
1answer
28 views

QGIS Reprojecting csv point file to projected CRS

This is a problem I have been struggling with quite a bit and so far have not found a good solution, so I hope to find some help here or an eyeopener where I have gone wrong so far. Using QGIS 2.10.1 ...
0
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0answers
5 views

qgis print composer fails on Mac (Mavericks)

For the last few versions of qgis, including the current 2.10, I have been unable to use the Print Composer to output maps. After choosing Print Composer from the menu, a tiny window pops up, with ...
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0answers
15 views

QGIS Heatmap Plug: Filling a radius with one color

I'm using the heat map plug in and I want to fill in my circles with just one color that corresponds with a specific color along a gradient. My tinkering has not been fruitful and every tutorial I've ...
0
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0answers
14 views

Is QGIS Server working like this?

On CentOS 7 I have QGIS Server and QGIS Desktop installed. In QGIS Desktop I created a project with raster and vector data and saved it in a ".qgs" file. Then I copied the file in ...
2
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1answer
21 views

QGIS GRASS raster to GeoTiff

First of all: Windows 8.1 QGIS 2.8.2 Wien My problem is that I used the GRASS module r.watershed to delineate watersheds and get flows with a DEM. It worked fine so everything is OK so far. But ...
1
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1answer
24 views

How to merge(transfer) one layer into another postgis layer?

I want to merge 2 layer which have identical structure. First layer is from postgres database table say "layer1" and other layer is shapefile say "layer2". I want to merge layer2 "INTO" layer1 (NOT ...
3
votes
1answer
43 views

CRS does not match after upgrade to QGIS 2.2

QGIS project, which was saved in 2.0 has defined CRS for project as a whole and for each of the layers. When I open the project in QGIS 2.2 and higher, one of the layers is shifted and does not match ...
2
votes
1answer
103 views

Copy first row of attributes and paste for each feature

In a newly digitised polyline vector layer, there are 7 columns attributes value that are choosen inside a value map combo-box that MUST be exactly the same for every newly digitised line (I choose ...