ordering columns

dear colleagues, who has save my job at various situations:

i'm dealining with a code in topographic analysis, the requiered assistance is next:

i got a table A

 A=

 379  700782,872000000  6015755,46600000  700487,673000000  6015992,71900000
121  700487,673000000  6015992,71900000  700563,348000000     6016086,87700000
379  700563,348000000  6016086,87700000  700858,548000000  6015849,62400000
398  700487,673000000  6015992,71900000  700858,548000000  6015849,62400000
398  700782,872000000  6015755,46600000  700563,348000000  6016086,87700000
121  700782,872000000  6015755,46600000  700858,548000000  6015849,62400000

composed by various

the first is g, and the rest are defined as x1, y1, x2, y2

the question is:

i need to order the table rows with the minor values of the pairs of rows x1 and y1 in ascendent order from top to bottom.

conditions:

the entire row is not modifiable, maintaining intact the rows structure, because are pair of coordinates.

so the requested that i have found in the example before is:

 121  700487,673000000  6015992,71900000  700563,348000000  6016086,87700000
 121  700782,872000000  6015755,46600000  700858,548000000  6015849,62400000

there are two possibilities, beacuse exist and x and an y values¡¡¡¡

what i'm searching for is the coordinate near to the center than the other (of the cartesian plane X=0 and Y=0). In other word, from this two answers select which-one is the more near of the center of the axes x and y (0,0)

i hope u understand the problem.... is a little bit complicated but well redacted.

Greetings from Congo

Answer 1

[Walter Roberson]

sortkeys = [A(:,2).^2+A(:,3).^2];
sortorder = sortrows(sortkeys);
sortedA = A(sortorder,:);

Note that this will sort entirely based upon distance from origin. If you would prefer to sort based upon g primarily and then distance from origin secondly, use

sortkeys = [A(:,1) A(:,2).^2+A(:,3).^2];

I do not bother to take the square root of the distance because doing so takes computation time and does not affect the sorting order.

[Jules Ray]

Walter: thanx for your answer...

ihave trying but fails in the las part of the script

sortedA = A(sortorder,:);

give this message

??? Subscript indices must either be real positive integers

or logicals.

any idea?

[Walter Roberson]

Sorry, the line

sortorder = sortrows(sortkeys);

should instead be

[sortedkeys, sortorder] = sortrows(sortkeys);