Epifanio's Blog Posts on Spatialguru.com

Control Ossimplanet using a joiystick (unfinished)

epifanio — Fri, 13 Feb 2009 09:17:17 -0900

Hi, as we can see here: External control of OssimPlanet, it is possible to navigate the planet using an external connection based on the TCP protocoll.

Using python with the module pygame it is possible to read the raw data from an usb device like joystick or joypad, then is easy to parse the data and send the navigation message to Ossimplanet.

Here a video on how it works : ossimplanet_joystick

Datum transformation in Python

epifanio — Sat, 14 Feb 2009 05:53:46 -0900

I’ll describe here a procedure for the evaluation of the tranforming parameters necessary to effect coordinates change among reference frames materialized on different Datum.

In order to have the changing of Datum it is used a geometric transformation of correspond (conforme) type through the resolution of a last squares system based on a homologous points series, in order toobtain the direct changing from plane coordinates in one of the two Datum to the corresponding in the other Datum.

Epsg code in python

epifanio — Mon, 09 Feb 2009 15:50:08 -0900

Python script to store epsg code, params and title in a dictionary and a simple search tool.

It's just a try ... episg.py

How to run in python :

    >>from episg import *
 
    >>test()  # print out some examples
 
	#  rep3('path to epsg','order',str('order'),'a')
	#  order (code,param,title)
	# 'c' epsg code 
	# 't' title
	# 'p' parameters
	# 'a' all
	# input : epsg code
	# output param, code, title (all)
 
	>>>output = rep3('/Users/sasha/Desktop/epsg','code',str('4326'),'a')
	>>>print output
 
['proj=longlat', 'ellps=WGS84', 'datum=WGS84', 'no_defs'] 4326 WGS 84

How to run in bash :

    $python episg.py /Users/sasha/Desktop/epsg code 3004 t
    $Monte Mario - Italy zone 2

The epsg file comes from the proj4-source code.