Wednesday 28 May 2014

Released first beta version of gvSIG CE 1.0.0 (64 bit OS)

From gvSIG CE developer announcement:

The first beta version of gvSIG CE 1.0.0 has just been released.
Downloads for Linux, Mac OS X and Windows here:
https://sourceforge.net/projects/gvsigce/files/beta-1/
All provided packages are for 64 bit operating systems.

Read the full announcement at:
http://gvsigce.sourceforge.net/wiki/index.php/GvSIG_CE_1.0.0_beta_1_release_notes

Sunday 25 May 2014

Plot of geological attitudes and traces in vertical sections along fold axes with Quantum GIS and qProf

The new released version of qProf (0.2.4), a Python plugin for Quantum GIS, allows to project geological attitudes and traces onto a vertical section along fold axes. On-the-fly reprojection of layers is supported.

The first step in using this plugin is creating a topographic profile by defining one (or more) source DEMs and a line layer that define the section, plus a line densify distance (generally of the order of the used DEM cell resolution) and an optional line order field (required only when the input geometry of the line layer is not sufficiently simple, see previous posts on the qProf plugin).
While for creating only topographic profiles the input line can be made up of many points and more than one DEM can be used, for geological projections the input line must be made up by just two points and only one DEM may be selected.
After having defined and created the profile using the tools in the "profile" tab, it is then possible to project geological attitudes or traces by using the commands in the "Project" tab.


Projection of geological attitudes

Geological attitudes will be stored in a point layer, with the measured dip direction and dip angle of the features in two distinct fields of the attribute table.
The commands are available from the "Geological attitudes" subwindow.
The projection of geological attitudes may be applied via different methodologies: (a) the nearest intersection point between the geological plane of a feature and the section plane; (b) using a common projection ("fold") axis for all features; (c) using individual axes for each attitude, with two numeric fields storing trend and plunge values.
If some data are selected, only those selected will be plotted, otherwise all layer features will be used. Labels can also be added to projected measures.
It is possible to cumulate in a single analysis session more sub-analyses, distinguishing them via different colors. Previous sub-analyses can be removed with the 'Reset geological attitudes' button.
Data can be saved as csv files or shapefiles.


A plot example, with attitudes labelled by original trend and plunge values, is in the figure below.



Projection of line traces

Line traces can represent the intersection of geological surfaces with the topography. When these surfaces are cylindrically folded, it is possible to projected the traces onto the section via a user-defined fold axis. The elevation information will be derived from the chosen DEM.
The commands are available from the "Geological traces" subwindow.
A line layer has to be chosen, with the name of the id field and a value for the line densification.
Trend and plunge of the projection axis will be defined, and a color chosen for the line plotting.
Different subanalyses, with different projection axes, can be differentiated by using different colors.
Previous analyses can be eliminated with the "Reset traces" command.
Results can be saved as text file, storing id-s-z values (where s is the horizontal distance from the section start) for each resulting point.



An example of the output is below. In this case, only geological traces are plotted. In general, both geological traces and attitudes can be plotted in the same section.



Installation

qProf can be installed from Quantum GIS via the plugin manager, or downloaded and unzipped in the Python plugin folder from:


For bug segnalation:
or write directly to alberti.m65@gmail.com (also for improvement requests or questions).
 

Friday 9 May 2014

Interactive map of small particle air pollution in world cities

In the Guardian web site an interactive map, based on the data of the World Health Organization, is available:
http://www.theguardian.com/news/datablog/interactive/2014/may/08/exposure-air-pollution-city-map
North America has lower pollution levels than in European states, with south-eastern European countries having the highest pollutions for Europe. India, China, Mongolia, Pakistan, Afghanistan, Iran present the highest levels in the world, together with many Middle East cities.

Monday 5 May 2014

Traduzione del manuale di QGis in italiano: vuoi contribuire con una donazione?

"QGIS è un software open source molto potente sviluppato interamente da volontari. Ma cosa sarebbe un software senza un'accurata documentazione? 
Una nuova versione di QGIS viene rilasciata ogni 4 mesi e di conseguenza la documentazione cambia ed è necessario aggiornare il manuale con le nuove funzionalità in modo che tutti siano in grado di sfruttarlo al massimo.

Siamo un gruppo di volontari che nel tempo libero crea, mantiene e traduce la documentazione di QGIS. Aiutaci con un piccolo contributo!"