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Hi,<br>
<br>
If you assume that the transform is linear and can be described by<br>
a matrix T such that B = T*A, then you merely get T as<br>
T = B / A<br>
-->T = B/A<br>
T =<br>
<br>
0. 0. 0. 0. <br>
0. 80113.778 - 80081.268 0. <br>
0. - 11913.312 11955.211 0. <br>
0. 92027.09 - 92036.479 0. <br>
<br>
then, checking that T*A gives B :<br>
-->T*A<br>
ans =<br>
0. 0. <br>
2131. 1534. <br>
2131. 1.455D-11 <br>
- 9.313D-10 1534. <br>
<br>
-->B<br>
B =<br>
0. 0. <br>
2131. 1534. <br>
2131. 0. <br>
0. 1534. <br>
<br>
// So, it's OK. T*A has some residues as big as ~10^-10 instead of 0,
due to <br>
// numerical approximations (finite number of digits in inputs and
during <br>
// the processing). <br>
<br>
Then, if you wish to decompose T as a rotation o translation o scaling,<br>
it is an additional piece of work.<br>
<br>
HTH<br>
Samuel<br>
<br>
Le 12/10/2011 18:25, Capitao Obvio a écrit :
<blockquote
cite="mid:CAFZz7Xq4O6XgnKGN3g+Ef41L55KieNtwQHSMzqkjVG_P6W7yOA@mail.gmail.com"
type="cite">
<div>Hi!</div>
<div><br>
</div>
<div>I'm starting to work with Scilab, and I'm trying to figure out
how to work with matrices.</div>
<div><br>
</div>
<div>
<div>My goal is to find a way to convert any point from one system
into another.</div>
<div><br>
</div>
<div>My (failed) approach so far was to estimate the necessary
rotation, translation and scale; but it didn't work quite well, because
the second map is slightly distorted (probably due perspective).</div>
</div>
<div><br>
</div>
<div>Being a bit more specific: </div>
<div><br>
</div>
<div>I have the following points:</div>
<div><br>
</div>
<div>A = [</div>
<div><span style="white-space: pre-wrap;"> </span>[52.363965,
4.892435],</div>
<div><span style="white-space: pre-wrap;"> </span>[52.384611,
4.898272],</div>
<div><span style="white-space: pre-wrap;"> </span>[52.379267,
4.881105],</div>
<div><span style="white-space: pre-wrap;"> </span>[52.369678,
4.911489],</div>
<div>]</div>
<div><br>
</div>
<div><br>
</div>
<div>They correspond to these points:</div>
<div><br>
</div>
<div>B = [</div>
<div><span style="white-space: pre-wrap;"> </span>[0, 0],</div>
<div>
<span style="white-space: pre-wrap;"> </span>[2131, 1534],</div>
<div><span style="white-space: pre-wrap;"> </span>[2131, 0],</div>
<div><span style="white-space: pre-wrap;"> </span>[0, 1534],</div>
<div>]</div>
<div><br>
</div>
<div>Do you have any suggestions on how to calculate tje transform
from A to B?</div>
<div><br>
</div>
<div>Thanks in advance,</div>
<div><br>
</div>
<div>Cap.</div>
<div><br>
</div>
</blockquote>
<br>
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