I'm Jean-Philippe Gauthier and I work for Environment Canada as a software specialist in scientific programming and visualization. We have been using Tcl/Tk since the 90's and have built many advanced tools for scientific visualisation and data manipulation.
http://eer.cmc.ec.gc.ca/index_e.php?page=s_software/spi/spi_e.html
SEH -- SPI looks extremely impressive. I tried to get the source code from the subversion repository mentioned in the INSTALL.txt file in the download section of the site, but it appears to be no longer active. Any idea where the source now resides?