Saturday, March 14, 2009

Unit Conversion

Neither Google nor ConvertAll know about Scruples. Both are convenient ways to convert units. The unix console utility (non-GUI) Units is my choice, so far, as it knows at least one unit, about which the two flashy tools do not.

I installed ConvertAll through Synaptic on Ubuntu. It is written in python using the QT library, so it is usable on Windoze as well as GNU/Linux systems. It's a GUI solution. It doesn't know about scruples, but it is claimed to work well with composite units, such as Kg/m/hr

In the google search bar, I enter "2 scruples in g". Google doesn't know about scruples either.

Units wins the first round. And it's easy to use.

Saturday, March 7, 2009

Some ideas for new projects

Weekends are good. This morning I started poking around the Inet. Here are a couple of nice things I found out about that I can use in my classes. That NFWF grant we lost because we had so much trouble spending out money? That would come in real handy just now.

GeoWall?

Today, I discovered this page: A tour of the Mariana Subduction System . Guess what? It's available as an "ArcScene GeoWall visualization of Mariana 3-D topography and earthquake distribution".

It can be done in GNU/Linux. I think Gentoo would be more appropriate, but one possible option is available out of the box, for Ubuntu, my current system of default choice. One package is "viewer" and it might be around. Another is "inventor". It looks hairy. And why not? It involves projecting a scene through two projectors, superimposed. Let me guess: with polarized glasses.

I saw such a system at the University of Texas Texas Museum of Natural History---a flythrough of a vertebrate skeleton. Which vertebrate? Don't want to spoil it for you.

Bilko

http://www.noc.soton.ac.uk/bilko/index.php

...for learning and teaching remote sensing image analysis skills. Current lessons teach the application of remote sensing to oceanography and coastal management, but Bilko routines may be applied to the analysis of any image in an appropriate format, and include a wide range of standard image processing functions.

Supported by UNESCO, Bilko is available to registered users absolutely free!


Wednesday, March 4, 2009

Machine meltdown experience, unnumbered

This week I've been working out how to synchronize systems using git. I've been monkeying around with Emacs Org-mode for a while, both at home and at work, and at infrequent times on a laptop. How can I keep both work environments pretty well evenly matched, so I can work on all of my little projects on both machines (or all three)? Git and a USB flash drive. I won't get into that now, but it's pretty much working out. I have found I need to set the UID (User ID) and/or the GID (Group ID) numbers the same on both systems, and I have implemented a "git" group to which my user (me) on both machines belongs, so there is no conflict when pushing today's work to the repository on the USB stick. It seems to be almost there, as far as my simple use case is concerned.

However, at one point, last friday, I had been working fairly hard on some files that I wanted to be synchronized at home, and I tried to push the changes to the USB stick. The write failed due to lack of permissions, so I sloppily did a "sudo chmod -R a+rw " and was able to recover. After I figured out the permissions might be at least part of the problem! It worked, but in the meantime, I, knowing-just-enough-to-be-dangerous, flailed at the keyboard (I recommend Keytronic), and managed, unknowingly, to mess the settings up in the /etc/group file: on Monday, I was unable to access the groups and users tool to try to solve my problem with permissions---on which I had researched all weekend.

This all to tell you that I was left on Monday with a machine that promised to be unrecoverable. At least by me. But, lo! and behold! On that machine was an unused partition---a Windows partition, and hence an unwanted one. An unneeded one, especially since I was now able to run windows in virtual box as needed. So I quickly installed Ubuntu Intrepid Ibex over lunch, and went back to it before I went home.

Chapter II. Why you need to run dpkg --get-selections

I ran dpkg --get-selections > selections-.

This gives me a list of all the packages on my current system. Lucky my system was at least running! I tucked these away in a file on the current ~/ (home directory), and rebooted the newly made Intrepid Ibex install.

I have installed various GNU/Linuces, dozens of times. Ubuntu is now a favorite because it is painless, and good. It does almost everything. (I still want to get another Gentoo Box going, but the amount of work would be intensive.) My experience has taught me a few routine steps to take to get the machine into working order, MY WAY. It is taking less and less all the time.

This time, however, it went even faster. With my "selections-" file, I started Synaptic, and told it to read this list. (Read Marks). Now the new system has a long list of most of the software that I have working on the old system. It starts downloading them. It says 2d and some. But in the evening the net is faster, and by morning, when I got to work, my machine was up and running, with most of the important bits and pieces I had installed, and also updated for the 4 or 5 months since that CD was assembled by Ubuntu. Pretty impressive. A few tweaks here. A few tweaks there. And the machine is at least functional! It will take little time to be back in the saddle, at 100%, on that steed.

What are my little tweaks? Here are a few
  1. Display some icons on the panel, and place two more panels on the left and right sides. These are made moveable, and expandable, and put at the top, extending down from the top panel, so extra icons can be spilled over onto them like ears. This has been a boon in real estate for icons.
  2. System->Preferences->Windows: set so mouseover raises windows, and to roll up on click of the title bar.
  3. Install emacs-snapshot and a bunch of it's friends.
  4. Firefox add-ons I have met: downthemall, video download helper, tableclipboard tool, zotero, recently flash got, multiple tab handler (allows duplicate tabs, etc), delicious (for the past two weeks, experimental.
  5. On the Firefox bookmark bar, in install a folder called "WLOG" (weblog) where I can pull the little icons from the left end of the location bar to make a bookmark. Just pull it over and drop it onto the WLOG folder. Very useful.
  6. Sometimes compiz configuration tool (forgot the name). The main thing I miss on Gnome is a way to move windows from workspace to workspace by dragging. Spinning cube is nice, but too much of a drag.
  7. Set up an array of "folders" (directories). I haven't figured this one out---perpetually seeking a simplified, hierarchical arrangement that isn't difficult to navigate.
FOLDERS:
  1. I establish too many at the level of ~/: Library (link to separate partition for PDFs); Downloads (where I direct all downloads---this is a candidate for modification, as I would prefer to sort things now rather than later), Work related main directory.
  2. I've been keeping old work around for longer than I am willing to remember. So many subdirs from projects of years ago are still hanging around---all of them meaning to be worked on sooner or later (maybe org mode can help with this). I have the following top level directory trees set aside for various kinds of these: Projects; WORKBENCH; STUDY.
  3. New idea: ~/SCRAPBOOK for all the stuff that hangs around the Desktop and ~/ directories that just stays around and I am unwilling to get rid of. Maybe ~/ATTIC is next.
  4. Another idea that hasn't found it's correct niche: ~/TOP_SHELF. I thought of this after I tried a little applet called top shelf, a place to store things short term, one means to get back to right away. One of the nice things about the new KDE is the window-like desktop. I have tried to implement something of this kind, with no borders, just a place that can display---or be temporarily out of the way. There seem to be two kinds of these top shelves: the top shelf that is too high to reach, with stuff one wants close around; and the back shelf just above the desk where a few cherished and often thought about and used items reside. Need to rename these.
  5. ~/MUSIC; ~/VIDEOS; ~/IMAGES (for teaching stuff); ~/PHOTOS.

  1. I also install several programs by hand, so I immediately install build_essential. The main programs I do by hand are XTide and Xephem. Each of them requires other libraries and tools, so I install them.
  2. Gscan2pdf is getting good. My scanner is problematical. When it is working, gscan2pdf is working too.





Chapter III. Permissions and Flash Drives


That's another story.