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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html lang="en-us">
<head>
<meta name="viewport" content="width=device-width">
<meta http-equiv="Content-Type" content=
"text/html; charset=utf-8">
<meta http-equiv="Content-Language" content="en-us">
<title>Maidenhead grid long/lat calculator not limited to 6
characters</title>
</head>
<body>
<h1>Maidenhead grid -- longitude / latitude calculator not limited
to 6 characters</h1>
<p>The <a href=
"http://en.wikipedia.org/wiki/Maidenhead_Locator_System">Maidenhead
Locator System</a> is a grid system used by amateur radio
operators. I crudely implemented a Maidenhead grid to
longitude/latitude calculator, not limited to the 6 characters as
often seen with other programs. Written in a one-time <a href=
"http://www.python.org/">python</a> spree here on <a href=
"http://www.debian.org/">Debian GNU/Linux</a>. Download: <a href=
"programs/lonlat2maiden">lonlat2maiden</a>, <a href=
"programs/maiden2lonlat">maiden2lonlat</a>. See my <a href=
"notes.txt">notes</a>, <a href="programs/rkanters.zip">Kanters'
2004</a>, <a href="http://www.g1ogy.com/projects/gps/">G1OGY's
2008</a> augmentations.</p>
<p>First, in case you use DMS notation, convert it into decimal
degrees,</p>
<p><code>$ set 120d51\'57.74\"E 24d10\'54.14\"N ; echo
$@</code></p>
<p>120d51'57.74"E 24d10'54.14"N</p>
<p><code>$ set $(echo $@ | <a href=
"http://trac.osgeo.org/proj/">cs2cs</a> +proj=latlong -f %.8f) ;
echo $1 $2</code></p>
<p>120.86603889 24.18170556</p>
<p>Now we are ready to go,</p>
<p><code>$ echo $1 $2 | lonlat2maiden</code></p>
<p>PL04KE</p>
<p><code>#arbitrarily picking 22:</code></p>
<p><code>$ echo $1 $2 | lonlat2maiden 22</code></p>
<p>PL04KE33WO16WF07TP38UR</p>
<p><code>$ echo $1 $2 | lonlat2maiden 22 |
maiden2lonlat</code></p>
<p>120.86603889 24.18170556</p>
<p><code>$ echo $1 $2 | lonlat2maiden 22 | maiden2lonlat | cs2cs
+proj=latlong</code></p>
<p>120d51'57.74"E 24d10'54.14"N 0.000</p>
<p>By the way, as to just how many digits one needs for what
granularity, we examine what the smallest length one can
distinguish with the <em>latitude</em> parameter as we increase
string length:</p>
<pre>
Len meters example
2 1111200.0000 PL
4 111120.0000 PL04
6 4630.0000 PL04KE
8 463.0000 PL04KE33
10 19.2917 PL04KE33WO
12 1.9292 PL04KE33WO16
14 0.0804 PL04KE33WO16WE
16 0.0080 PL04KE33WO16WE57
18 0.0003 PL04KE33WO16WE57NA
</pre>
<p>So, to dazzle your friends with millimeter precision, one need
not make one's <a href="../../location/coordinates.html">vanity
Maidenhead locator</a> too long after all. (<a href=
"programs/significance">Code used to make above output</a>)</p>
<p>Hmmm, the Maidenhead system is sort of like <a href=
"../taipower/index.html">Taiwan Power Company grids</a>.</p>
<hr>
<address>
<a href="../../index.html">Dan Jacobson</a>
</address>
<p><!-- hhmts start -->Last modified:
2015-02-15 08:57:21 +0800<!-- hhmts end --></p>
</body>
</html>