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

learn more… | top users | synonyms (1)

0
votes
0answers
3 views

Export background tile map to raster file

In QGIS I managed to display the ship traffic density from marinetraffic.com as a background tile map using the TileLayer plugin. Here is my TileLayer.tsv file: #title credit serviceUrl yOriginTop ...
1
vote
0answers
35 views

Generating Canal on DEM using ArcGIS for Desktop?

I want to generate a canal going from point A to B with a given slope. The canal should be on the underlying DEM. Is there any way to do this with the tools in ArcGIS 10 or do I have to do it ...
3
votes
1answer
21 views

Identify all continuous networks in a dataset

I have a set of pedestrian streets for a city. I would like to assign all of the streets that can be reached to one another along a continuous network to a unique group. I am wondering if there’s an ...
0
votes
0answers
14 views

Querying related tables in QGIS

I have a parcel layer and a table of property sales. I have the two tables related (it is a one-to-many relationship) in a QGIS project so that when you click on a parcel you see all the related ...
1
vote
1answer
21 views

QGIS syntax raster calculator

I'm working with QGIS and I want to reclassify a raster in different ranges. Using the following statement does not work even recognized as valid (2950 <= "dem_tallat @ 1"> = 3050) = 3000 ...
0
votes
0answers
16 views

Exported QGIS composer map using Openlayers base map has city labels shrunken

I've created a map in QGIS composer and I'm using the Google physical base map via the openlayers plugin. When working with the map in QGIS canvas & the composer view, I see city names with ...
1
vote
2answers
52 views

How to draw a polygon given a distance and bearing in QGIS

Apologies if this question has been asked before I'm not come across it. I want to draw a polygon given a length and a bearing, basically a square with lenght 1m. I cant seem to manage it with the ...
0
votes
1answer
28 views

Using QGIS and PostGIS for multi-user capabilities, similar to ArcSDE for ArcGIS [duplicate]

I have previously used ArcSDE technology with Microsoft SQL Server to allow for multi-user database editing. My ESRI licenses have recently ran out and I have been using QGIS for my GIS work. I am ...
1
vote
0answers
22 views

Guidelines for publishing large datasets on QGIS Web Client

Can anybody provide simple guidance to publishing large datasets on QGIS web client? I have a mixture of shapefiles and rasters to display. Biggest shapefile is 230 MB. Biggest raster is 1.4GB. At ...
2
votes
1answer
34 views

How to remove abnormalities from the Green vegetation fraction

Study area was clipped by using the shape file from Band 3 and Band 4. First, Band 3 and Band 4 were converted to at-satellite brightness temperature by using the built-in function in semi-automated ...
2
votes
2answers
34 views

QGIS 2.4.0 marker line interval does not work properly when line is bending

I am trying to style a line using marker line option. When I am using styling the line in the style window everything looks nice as you can see on the print screen bellow. I am using three line ...
3
votes
2answers
60 views

QGIS Installation on Windows

I'm newbie to QGIS and to this forum. I want to develop application using Qt on QGIS to real time updation/mapping of a symbol using GPS co-ordinates. Initially i have installed QGIS on Windows 32 ...
0
votes
1answer
18 views

osm2pgsql doesn't run in a QGis plugin

I have a problem with osm2pgsql when it runs in a qgis plugin. The function i use looks like this: osm2pgsql = "osm2pgsql -s -d {databaseName} -U {databaseUser} -H {databaseHost} -E ...
3
votes
1answer
30 views

matching shape file to csv within QGIS - all strings

I am trying to link a csv to a shape file using the method as described in this tutorial: http://maps.cga.harvard.edu/qgis/wkshop/join_csv.php It seems to work fine but the problem is that the csv ...
0
votes
0answers
17 views

Exporting QGIS Raster/Vector layers into one PDF? [duplicate]

I have seen a similiar post to this a while back (Is it possible to export GeoPDF from QGIS?), and thought I would try asking it again to see if there has been any improvement or new knowledge on ...
3
votes
2answers
64 views

Visualize overlapping line vertices in QGIS

I am trying to inspect the vertices of some linestrings in QGIS 2.4. My goal is to visualize every vertex of a line and easily find those that are duplicated. To clarify this, for an example line ...
3
votes
1answer
56 views

How do I merge DEM rasters correctly?

I've been struggling with this problem for awhile. Here is a curvature raster to illustrate the problem. I'm using 10m DEM rasters from the NRCS Data Gateway for a large portion of California. The ...
1
vote
1answer
16 views

QGIS: OSM Landscape layer not printed

I am new in GIS and I am trying to print a new map. If I use Google Street and web layer, it got printed without problem in the composer, but OSM Landscape does not appear on the printed document (it ...
3
votes
2answers
44 views

Locate points that are within a certain distance of other points in QGIS

I need a way of locating all points in my dataset that are within a certain distance of any other point. For example, in the following data set in which EASTING AND NORTHING are British National Grid ...
2
votes
1answer
29 views

View with sequence in QGIS 2.4

In postgres, I created a view with a sequence nextval() to have an unique id (called vid). I tried to vizualise this view in QGIS but it failed. It seems that nexval() causes some issue according to a ...
3
votes
1answer
54 views

Distincly color world map by language in QGIS 2.4

For a map of Wikipedia language prefixes, I need to color a map by a country's value in the 'language' column. I. e. all countries with the same language worldwide should share a color, which they ...
2
votes
0answers
27 views

How to calculate surface out of GPS points in QGIS

I have uploaded several squares (which consist out of 4 GPS points, not connected). I need the total surface of the squares. Is there a simple way of doing this? Do I create polygons and than ...
-1
votes
0answers
35 views

How to load Google Satellite images in QGIS using python [on hold]

I have to write a python program to remove all the existing vector layers in QGIS. I then have to write a python program to load the Google satellite images. Please help me by answering this ...
0
votes
1answer
25 views

How to manage the CRS of Open-Layers plugin in QGIS?

I am working with OpenLayers plugin in QGIS 1.8 but I am not sure on how should I manage thc CRS. The defaul CRS for Googles/Bing layers is WGS84/Pseudo Mercator (EPGS:3857) but I am not sure on the ...
0
votes
1answer
22 views

How to run and debug PyQGIS scripts in PyCharm Community Edition 3.4.1

I am working with creating plugins for QGIS 2.4.0 (Chugiak). I am curious to know how I can write the codes, and debug them in the environment I am comfortable in, i.e. PyCharm Community Edition ...
1
vote
0answers
12 views

QGIS PointConnector Plugin - x out of x lines not drawn

Unfortunately every try to generate lines between points (.shp) with ids (1-6) and a csv-file with from - to values failed. Maybe you can give me a hint whats wrong with my workflow? 1) I generated a ...
0
votes
2answers
56 views

How to draw a perfect circle with a set radius in meters on map?

Following this istructions on how to draw a circle I can make buffer layer on each point I need. I am not able to draw perfects circle because the buffer will be elliptic? The CSR is EPSG:4326 - WGS ...
0
votes
0answers
25 views

Open a *.qgs project file in API, why maps do not show?

I'm using QGIS-2.4.0 API. I saved a test.qgs file in QGIS Desktop, in this project, there is one layer that is visible in it. Then I open the test.qgs project file in QGIS API to developing an App, ...
4
votes
0answers
41 views

Why are my calls to SAGA routines in QGIS not working cross platform?

The ability to write and run cross platform scripts for QGIS using python is OUTSTANDING! However, when I try to run the SAGA:MERGESHAPESLAYERS algorithm from a python script it works fine in windows ...
5
votes
0answers
66 views

How to produce high-resolution DEMs from new Sentinel-1 data?

This is a general question relating to the new Sentinel-1 data. I'm interested in the potential for using this data to create high resolution DEMs in GIS (I use QGIS), to investigate archaeological ...
2
votes
0answers
45 views

Issue with dissolving a polygons layer in QGIS 2.4

I downloaded a dataset of roads and parks from OSM. I then buffered the roads and merged with the parks. Now - all i want is to dissolve / union all the features in the merged layer. I fail to do it ...
1
vote
1answer
33 views

How to save multiple layers from QGIS to a Spatialite db?

I thought I had asked this before but I can't find any trace of it. Each time I save a layer from QGIS as a spatialite it insists on creating a new db ( if you select a existing db you are asked ...
1
vote
1answer
27 views

QGIS: How to get Symbols saved in GPX Files

I have some waypoint layers that contain different types of points and I distinguish these in QGIS by different symbols and colours. I want to export these to a GPX file that I can download to my GPS ...
2
votes
0answers
21 views

How to move to the next feature in the polygon with user keyboard inputs

I am new to this qgis i have one question. There is one rectangle and it is divided into some 20 grids.I wrote a program to zoom into the each feature.but if i am in one feature i want to move to the ...
1
vote
1answer
36 views

Open Source solution to batch process shortest distance between points along road networks?

I have the locations geocoded (a fairly small dataset, ~200), but I haven't found a straightforward way to load these data into QGIS and perform network analysis between nodes. Any suggestions? ...
1
vote
1answer
26 views

Convert From Northing/Eastings to Latitude/Longitude with QGIS

How can I convert a file with the projection below (NAD83) to one with Latitude and Longitude? The import file is a SHP file and I would like to export back out a SHP file. +proj=tmerc +lat_0=0 ...
2
votes
0answers
22 views

Assigning Color Ramp using PyQGIS

According to the PyQGIS Cookbook, a color ramp can be assigned in the following way: rlayer.setColorShadingAlgorithm(QgsRasterLayer.ColorRampShader) lst = [ QgsColorRampShader.ColorRampItem(0, ...
0
votes
1answer
55 views

Creating Map from database

I'd like some general advice on creating dynamic maps. I have a bunch of geospatial points saved on SQL Server and PostgreSQL. People will enter new data into the databases from time to time. I want ...
1
vote
2answers
40 views

Contour of single feature on QGIS

I'm trying to extract one single contour line at given elevation from a DEM. Taking into account that I want only one contour and not all contours with the given elevation, is there a way to do it in ...
1
vote
1answer
13 views

Print with different settings of layer view?

Using QGIS is it possible to print on the same paper two windows with different settings of layer? I mean: window1: layer1 ON - layer2 OFF window2: layer1 OFF - layer2 ON
2
votes
2answers
46 views

Printing A3 format map

I have a question about printing A3 map from QGIS. I'm going to make A3 map of one country and nearby countries, digitalise borders etc. I want to save it to A3 format, but I have only A4 printer, ...
1
vote
1answer
26 views

How to load territorial maps on QGIS from web?

Is it possible to use QGIS like Google Earth? I need to draw simple shapes on territorial maps. I would like to do that without using multiple files for each part of the Earth. I use QGIS 1.8, but I ...
1
vote
0answers
26 views

Raster calculation with string in modeler

In my model I have one raster file and also a string input (factor for further calculation). I tried to use the grass r.mapcalculator where I can find the raster and also the string input. I tried to ...
1
vote
1answer
19 views

Problem by changing the order of Layers in QGis Layer Tree

I'm using QGis 2.4 on a virtual machine (Ubuntu 14.4 with XFCE). I'm connected to the VM via vncviewer, what works pretty well. But now I want to add some more layers to an existing QGis Project. ...
2
votes
2answers
69 views

Can't transform lines to polygons

I have a similar question to: How to join lines in QGIS for later using "lines to poly"? I have a line shapefile that I wish to transform into a polygon shapefile. After making some ...
1
vote
1answer
27 views

How do you extract the data behind a raster histogram

Bit of a newbie, so this may be a daft question. I have an .ecw picture - it is has no CRS, as it is a picture taken at ground level with an NIR camera. It was originally converted from a RAW image. ...
1
vote
0answers
41 views

Geometric functions in field calculator in QGIS

I had a look in the manual of QGIS and I also browsed the Internet to find some useful information about the geometric functions of the field calculator. I've found this post but I'm still confused. ...
1
vote
1answer
28 views

Pattern Effect in Pie Charts in QGIS?

I have more than 3 attributes to add to pie charts in QGIS, so I need a patterned fill e.g.dots, lines. Using a grey scale gives white, black and grey but using different shades of grey doesn't work ...
1
vote
0answers
32 views

How can I get a .asc file to load into QGIS?

I got some files from an ag plane that are in ASCII format. I can not seem to be able to get them to load into QGIS without the This is a link to the file I am trying to use. ...
2
votes
0answers
25 views

infer the altitude from a DTM & finally provide it to point / evincere la altitudine da un DTM & finalmente fornirla a dei punti

I would like to complete a point vector's table with Z data. I am not able to take Z coordinate from a dtm (downloaded from ...