At risk of boring some people I will post once more on my star viewer app and report the latest development. It all started long ago as a Java / java-gnome exercise while I was doing an evening class on astronomy. Basically the program is based on a PostgresSQL database of celestial coordinates, which can be selected and projected via the brilliant Postgres spatial extension, PostGIS. A simple GUI allows the user to select stars by constellation and provides an image, annotated with the principal star names.
Now it has transmogrified from an astronomy exercise to a demonstrator of RPi capability.
First, a a brief resumé:
- it was ported to Raspberry Pi – to see if I could, and retaining Java as its language and java-gnome as its GUI
- then re-engineered to Python 2, using PyGTK for the GUI
- then up-graded to Python 3, introducing TkInter as the GUI
- a web version was developed using an Apache HTTP Server module called mod_python as a CGI type interface – still accessing the PostGIS enabled database server for stereographic projections of star maps
Now a new web technique has been adopted, relying on a new Apache module called mod_wsgi which supports the Python WSGI interface, i.e. the Python Web Server Gateway Interface. WSGI is said to provide a standard way to interface different web-apps without hassle and it does sem to work pretty well when you get the hang of it.
The end-user sees pretty little difference of course: