Home Accessibility Courses Twitter The Mouth Facebook Resources Site Map About Us Contact
 
Python and Tcl - public course schedule [here]
Private courses on your site - see [here]
Please ask about maintenance training for Perl, PHP, Lua, etc
 
Working out distance between places, using OS grid references and a program in Tcl

In Great Britain, locations have Ordnance Survey grid reference positions which place them to within 100 metres. Our training centre / hotel is at ST907633 - that's
  100 km square ST
  90.7 km into that square from the west side
  63.3 km into that squate from the south side

One of the requirements that I've got at present is to take 597 survey inputs from the TransWilts survey we did last October and come up with some metrics of journey length. From previous work I have details of all the stations on the network, including their OS references, [here], and I've got the layout of the 100 km squares in a data file [here].

As I'm teaching a Tcl course this week, I've chosen to write my distance calculation code in that language. Here's the program in use - calculating the dictance from Melksham to Swindon, and from Swindon on to London Paddington.

  munchkin:survey grahamellis$ tclsh distance_between
  What are the grid reference on your journey (space separated?)
        ST899646 SU149853 TQ265814
  32.46
  111.67
  munchkin:survey grahamellis$


(Take a look at the source code which is commented if you want to see the logic in Tcl. It makes strong use of string handling and lists in Tcl, and you'll see examples of for, foreach and while loops too - they make an excellent comparison)
(written 2015-03-11)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
T205 - Tcl/Tk - String Handling in Tcl
  [4454] Everything is a string - even a list - (2015-03-11)
  [4205] Regular Expression Substitution - Tcl - (2013-11-12)
  [3576] Tcl - apparently odd behaviour of string trimleft - (2012-01-13)
  [3285] Extracting data from a string / line from file - Tcl - (2011-05-10)
  [3192] Tcl - Some example of HOW TO in handling data files and formats - (2011-03-04)
  [2472] split and join in tcl and expect - (2009-10-23)
  [1601] Replacing the last comma with an and - (2008-04-04)
  [1410] Tcl / regsub - changing a string and using interesting bits - (2007-10-27)
  [1403] Square Bracket protection in Tcl - (2007-10-23)
  [943] Matching within multiline strings, and ignoring case in regular expressions - (2006-11-25)
  [779] The fragility of pancakes - and better structures - (2006-06-26)
  [404] How to check that a string contains a number in Tcl - (2005-08-06)

T206 - Tcl/Tk - Lists
  [4209] Lists in Tcl - fundamentals in a commented source code example - (2013-11-16)
  [3618] lists and struct::list in Tcl - Introduction to struct::list and examples - (2012-02-18)
  [3583] Expanding a list of parameters in Tcl - {*} and eval - (2012-01-17)
  [3582] Tcl collections - lists, dicts and array - (2012-01-16)
  [3415] User defined sorting and other uses of callbacks in Tcl and Tk - (2011-09-02)
  [3394] The difference between lists and strings - Tcl - (2011-08-16)
  [2468] What are Tcl lists? - (2009-10-22)
  [1405] Sorting in Tcl - lists and arrays - (2007-10-24)
  [1402] Tcl - append v lappend v concat - (2007-10-23)
  [1334] Stable sorting - Tcl, Perl and others - (2007-09-06)
  [1283] Generating traffic for network testing - (2007-07-29)
  [1282] Stringing together Tcl scripts - (2007-07-29)
  [781] Tcl - lappend v concat - (2006-06-27)
  [463] Splitting the difference - (2005-10-13)
  [144] Tcl sandwich - lists in Tcl - (2004-12-08)

T203 - Tcl/Tk - Conditionals and Loops
  [4323] Learning to program - Loop statements such as while - (2014-11-22)
  [4322] Learning to Program - the conditional statement (if) - (2014-11-21)
  [3571] Comparing loop commands in Tcl - (2012-01-06)
  [3570] Trapping errors in Tcl - the safety net that catch provides - (2012-01-06)
  [3397] Does a for loop evaluate its end condition once, or on every iteration? - (2011-08-18)
  [3189] Tcl - the danger of square brackets in a while command - (2011-03-02)
  [2681] Tcl - a great engineering language - (2010-03-17)
  [2471] A short form of if ... then ... else - (2009-10-23)
  [2261] Tcl - nice and nasty - (2009-06-29)
  [1696] Saying NOT in Perl, PHP, Python, Lua ... - (2008-07-04)
  [1477] Decisions - small ones, or big ones? - (2007-12-18)
  [1401] Tcl - using [] or {} for conditions in an if (and while) - (2007-10-23)
  [210] Joining lists in Tcl. Indirect variables in Tcl. - (2005-02-12)


Back to
Everything is a string - even a list
Previous and next
or
Horse's mouth home
Forward to
Objects in Tcl - iTcl - updated first steps example
Some other Articles
Managing the window size (and layout) in Tcl/Tk
A new Tcl/tk example - a window to show system status
Test framework for TCL - Tcltest - some examples
Objects in Tcl - iTcl - updated first steps example
Working out distance between places, using OS grid references and a program in Tcl
Tcl variable names - no real limits!
Binary data handling - Python and Perl
Running an operating system command from your Python program - the new way with the subprocess module
Deciding whether to use parameters, conditional statements or subclasses
4759 posts, page by page
Link to page ... 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96 at 50 posts per page


This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

Link to Ezine home page (for reading).
Link to Blogging home page (to add comments).

You can Add a comment or ranking to this page

© WELL HOUSE CONSULTANTS LTD., 2019: 404 The Spa • Melksham, Wiltshire • United Kingdom • SN12 6QL
PH: 01225 708225 • EMAIL: info@wellho.net • WEB: http://www.wellho.net • SKYPE: wellho

PAGE: http://www.wellho.net/mouth/4455_Wor ... n-Tcl.html • PAGE BUILT: Sat May 27 16:49:10 2017 • BUILD SYSTEM: WomanWithCat