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

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NDVI from raster to vector isnt working

I have question...can I make from raster img. vector file via qgis? Because Ive tried it on NDVI image and Ive only got one file with atribut table full of #null. Image is from landsat7... ...
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27 views

Obtaining NDVI data from selected area

I need to analyse NDVI (-1/1) change between years (05-10y). But still only under selected shapefile. To analyse the extent of each NDVI category. Any tips? I have tried to make vector from the NDVI ...
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1answer
46 views

“Browse” button returns python error in QGIS

I use the latest version of QGIS (2.8.2) in MAC and have se the default Python version 2.7. Moreover, I have installed all the required python modules and GDAL. It was working before, but now, when I ...
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1answer
21 views

Is it possible to export layers scale-based visibility to a webmap?

Is it possible to make or convert a QGIS map into an interactive webpage map? For example, I have layers that appear at certain zoom levels, is there a way to have that interaction on the map for ...
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0answers
24 views

Placing road labels only at map edges and road intersections in QGIS

I want to place road labels only near the map edges, and where roads intersect - as depicted by the red X's in the image. Background: I've seen the military do that in their topo maps, and I think ...
2
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0answers
18 views

Help Needed with QGIS Vector->Geoprocessing Tools->Difference [duplicate]

I'm trying to use the Vector Geo processing Difference Tool in QGIS to "take a bite" out of one polygon using another in another layer. The tool menu Difference icon is exactly what I'm trying to do - ...
0
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1answer
30 views

Create ID for each string attribute in QGIS

I'm trying to rasterize a vector layer by using an attribute filed stored as string, I got the confirmation through the GDAL mailinglist serv that gdal_rasterize does not work with string field. So my ...
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2answers
37 views

Where to get QGIS toolbar icons?

Does anybody know where to download the QGIS toolbar icons?
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1answer
22 views

How can I overlay city and borough names in QGIS with political boundaries?

This post is related to this one. The following images are from @Weinfried's answer. I was able to get the ITA_adm0.kmz, ITA_adm1.kmz, ITA_adm2.kmz, but not ITA_adm3.kmz, which for some reason does ...
1
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1answer
27 views

QGIS Coverage help

I am using QGIS 2.8.2 and everytime I try to load in a coverage type Shapefile, like forest density or population density it all comes up as the same color, but has the sections marked for the ...
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1answer
26 views

Generating elevation 'database' from NED IMG data

I'm starting to work with the NED 1/3 and 1/9 arc-second data. I've been using gdal in Python and QGIS to do some basic conversions of the raw .IMG data from USGS. My goal is to get elevation data of ...
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0answers
14 views

Vector data getting misaligned in final print in QGIS [duplicate]

My printcomposer view shows the data correctly aligned with background OSM/Google/Bing data but the final print makes it all misaligned. Data is in 3857 What can I do?
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0answers
24 views

How can I render heatmap contours from QGIS into tiles?

I have a heatmap and contours in QGIS, and I want to export these heatmaps as tiles. This works well with tiff, but I want to include contours into images, to make them look better. In QGIS, I can ...
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0answers
15 views

Loading Batch Parameters in QGIS [closed]

I usually work my batches in Excel and then copy/paste it into ArcGIS batch UI. Is it possible to do the same in QGIS? The tutorials I've seen show how to fill the interface line by line, only. I'm ...
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1answer
34 views

Adding the map canvas center to a composer label in QGIS

I am able to access the map canvas center in the python console in QGIS using qgis.utils.iface.mapCanvas().center() What I would like to do is get this into a map composer label. Is this ...
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0answers
22 views

How to format the labels of a UTM Grid in a map Layout/Print Composer

I am doing a map in for a small area (1.5km by 1.5km on UTM zone 14N). I want to know if it is possible (and how to do it) to format the labels of a UTM grid. This is exactly what I want to show a) ...
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0answers
22 views

QGIS DB-Manager: How do I hide a geometry column?

I created a table on a SpatiaLite DB using the DB-Manager: CREATE TABLE Lines ( line_id INTEGER NOT NULL PRIMARY KEY, name VARCHAR(256) NOT NULL); Then I "made it spatial": SELECT ...
1
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1answer
113 views

Calculating Area of Intersecting Polygons and Buffers

SO, in QGIS I have several points with 1km buffers around them; some of the buffers overlap. Within the buffers are a number of ponds, which I have a shapefile for. I want to calculate the area of ...
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2answers
26 views

QGIS create a line graph with attributes value on a section through the map

I wonder if I can make cross sections of GIS data (other than height). An example: I have a shapefile of a city with building plots and attribute values of the plot size. I want to choose a random ...
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0answers
12 views

Shifted point in pdf export on QGIS

When I print as PDF a work done with a shape point and OpenLayer plugin I notice that the point are shifted In the dual screen image you can see the pdf exported image (left) and the QGIS woriking ...
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0answers
22 views

cannot load moule sip qgis 2.8.2

i have an error when i launch the qgis 2.8.2 it says that the module sip cannot be load python 2.7 has been installed i am under ubuntu 14 please if you have any idea here is the message (in french ...
2
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1answer
22 views

PostGIS - interfacing with CADCORP 7.1 and QGIS - user 'postgres' can import, but no other roles can

I'm new to PostGIS (reasonably) - but I'm plagued with one on-going problem: I'm able to access PostGIS from various GIS systems using the main 'postgres' user. Using a newly created user ...
2
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0answers
38 views

How to edit the GUI of a QGIS plugin not made with the plugin builder?

I edited a python plugin's code and had to change the UI a bit as well. However, unlike in the plugins I made from scratch with the plugin builder, the UI doesn't automatically update in QGIS when I ...
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1answer
39 views

Setting PYTHONPATH for compiled QGIS version on Linux

I'm trying to set the PYTHONPATH in order to be able to load the qgis classes in a python console (not the QGIS Python one). I followed some resources I've found (PYQGIS Cookbook, and others) but I ...
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1answer
68 views

How to register “events” for linear referencing in pyqgis?

Is there an easy solution for recording events for a line crossing borders of zones in a polygon layer? I need to implement this in python using QGIS, thus pyqgis. The image attached illustrates what ...
1
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1answer
62 views

How to select polygon features that intersect a line feature using pyqgis?

Is there an easy way to select all features in a polygon layer that intersect (overlap) a line feature? I need to implement this in python using QGIS, thus pyqgis. This code illustrates what I am ...
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1answer
22 views

Why does the Contour Plugin failt to load in QGIS Valmiera?

Whenever i try to load the contour plugin. I get the error as follows: The same happens to when i try to load Qgis2leaf plugin... An error has occured while executing Python code: Traceback (most ...
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0answers
14 views

Installing exifread for QGIS photo2shape plugin for novice

I'm trying to install exifread so I can use the photo2shape QGIS plugin. I know nothing about python and I haven't been able to get it to work using the answers from previous questions. Can anyone ...
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2answers
46 views

Creating Protocolbuffer Binary Format (PBF) file using QGIS?

I have a set of geospatial data, lines (streets) in geojson and shp file format which which i want to convert to PBF (Protocolbuffer Binary Format). I am presently working with QGIS. Please does ...
2
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1answer
28 views

How to count points within the current Print composer atlas feature in QGIS 2.8?

In the print composer when generating an atlas, does anyone know how to show he feature count per each atlas coverage feature? For example, I have generated an atlas where each map is a different ...
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0answers
24 views

Add Vector Layer - Database OODBC does not work

What I am trying to do: Add a vector layer from an remote Oracle database. Platform: Linux Red hat 7 Database: Oracle 11g Connectivity via unixODBC Oracle Description: I tried to add a vector layer ...
2
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2answers
78 views

Attempt to install QGIS 2.8 on Ubuntu 15.04 installs old version instead

I previously had installed QGIS 2.8 with the GRASS plugin on Ubuntu 14.04. Through a chain of events I ended up having to do a clean install of Ubuntu 15.04, and am attempting to re-install QGIS 2.8. ...
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0answers
17 views

Integrate Qgis project to web based google api [closed]

I was planning to convert the shape file into KML which google map supports. However, my project also includes TimeManager and PostGIS database. How do I handle them?
7
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1answer
236 views

How to refer to another layer in the field calculator?

Is there a way to select an attribute from a polygon layer and insert the value into a virtual field of a point layer using "within" in the field calculator? CASE WHEN within($geometry, ...
1
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0answers
23 views

How to remove covering lines? [closed]

I have a shape file where there are polygons perfectly fitting, i created contour lines from all of the polygons so i have a shape containing only the lines. My problem is as the polygons were ...
2
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0answers
15 views

QGIS 2.8.1 (Windows 64bit). Setting snapping to the “decoration” grid?

I was wondering if anyone knew of a way to snap digitizing to the grid you can create in View>Decorations>Grid? I can't see anything in the manual or the menus so I am thinking there probably isn't ...
0
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1answer
13 views

QGIS geolocate a DBF file with another point layer by matching field

I have a DBF table and a SHP with points. I want to geolocate the DBF file using the points layer. Both match in a field called "unificationstring". I know how to do it in postgis but how can this be ...
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0answers
25 views

How to interpolate a Raster DTM

I have a GeoTIFF DTM produced from Agisoft Photoscan at 0.05 m resolution. However the interpolation used by the program to remove the riparian vegetation has used points from the channel, thus ...
2
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0answers
22 views

clipping raster changes raster values?

I am working with BIOCLIM temperature/precipitation layers and I have noticed that when I clip the global raster down to a specific region, something happens and the raster value at a specific point ...
1
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1answer
17 views

QGIS get currentfeature's color in the Expresions Builder

In QGIS Expression builder. I want to obtain the color code of the current feature. I mean: My layer contains lines, each one is painted with a different color. Now I want to assign that color to ...
1
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0answers
17 views

Display different symbols in QGIS using Point Displacement renderer

How to display different symbols (not different in size, different in shape and color) on the same point in QGIS 2.8 using Point Displacement renderer? I want my layout with symbols around the ...
2
votes
1answer
39 views

QGIS 2.8 OSM download with overpass fails

When trying to download OSM data in QGIS 2.8 I am using a layer to provide the extend for the requested data. The extend basically covers all the countries that share coast line of the Baltic sea ...
1
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1answer
37 views

Understanding QGIS scale dependent visibilty?

I cannot understand why the scale dependent visibility function does not want to work in QGIS. I'm using the latest version (2.8.1 Wien) and want to insert diagrams (pie/histogram) to illustrate ...
2
votes
0answers
32 views

QGIS: Edits in attribute table are not updated in Postgis database. Why?

As the title say. I edit values in the attribute tables of my QGIS project but there is no update to the database. I refreshed in QGIS as well as the database. What else do I need to do?
1
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0answers
27 views

How to convert poly-line contour feature class into heat map displaying heights [closed]

I'm looking for a way to be able to convert contour data (as lines) into a heat map that would display the data warmest at the highest points and coolest at the lowest. I have access to QGIS, ArcMap ...
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0answers
23 views

Projections way off on data imported into QGIS?

I have elevation data as a .shp from the USDA ARS and Hi-Res Orthoimages (Mystery Projection (UTM 15N?)) from the USGS website as geoTIFFs (plain NAD 83). I am trying to project all of the images ...
2
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0answers
22 views

Show dimensions on polygons

I have a shapefile that contains all of the property parcel lines in King County, WA. We are currently displaying this data through mapbox on our site with no issues. We would like to be able to show ...
2
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2answers
58 views

Create circle shapefile vector in QGIS

Is it possible to create a circle shapefile feature in QGIS, like it is possible to do in ArcMap? I am trying to digitise a map wich features roundabouts, which I'd like to be part of the same ...
1
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0answers
18 views

assign text values to selected subset in the attribute table in QGIS [closed]

I am using QGIS and I would like to generate a new string of text in the attribute table for a selected subset of features in a vector file. I cannot find an operator in the field calculator to ...
1
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0answers
15 views

Accessing elements Linestring and points from a DGN file and displaying both layers on QgsMapCanvas

I am using PyQGIS APIs to develop a standalone application which currently display's map data layers on QgsMapCanvas from .shp, .tif, .dgn files. I am able to do it for .shp and .tif but not for .dgn ...