One doesn't even need a print out of the photo--I 
log my microprobe spots by bringing my notebook 
computer along, opening the photo of the sample 
in CorelDraw (though most any drawing program 
should work for this), locking that layer and 
then adding circles over the photo in the 
appropriate places, which I colour code (redish 
for garnet, blue for white mica, brown for 
biotite, etc.), and I give each circle a name 
that matches the spot name recorded by the 
microprobe.  I also mark phases I check for 
composition but don't do an analysis on (like 
quartz) so that I have a record of those, 
too.  This is the habit I developed while 
analyzing experimental results, where I actually 
sit with the probe for each analysis, so there is 
plenty of time available to create the record in 
the drawing program while the probe does the analysis.

When doing my PhD instead of sitting with the 
probe while it did the analysis we would program 
the points to be done and then leave it to work 
overnight, so I used a different technique:  I 
drew marks of the spots on a print out of the 
photo and then later imported the X-Y coordinates 
from the probe into ArcMap and aligned a digital 
copy of the image with those points.  Usually it 
was only necessary to align two or three spots 
towards the edges of the group of them and all of 
the other spots would then show up on the image 
in the same places as I had marked on the paper.

Both methods are nice because one has the names 
of the spots and so can open the program and zoom 
straight in to a specific analysis point of 
interest. A word of warning:  If you use the 
ArcMap method and are later transferring to 
another university which does not have a ArcMap 
licence make good, annotated, printouts (jpg is 
good enough) of every sample, in case you want to 
look things up later.  It is annoying to have 
files with such useful data in them and not be 
able to open them on the new computer...

--Reia

at 09:44 31/08/2011, Jochen wrote:
>Hi David,
>
>isn't it better avoiding the problem in the 
>first place, either by logging probe spots (if 
>you have the equipment), or defining each 
>individual spot with the help of the backscatter 
>image, having a blow-up photo of the garnet at 
>hand. Modern microprobes also give you the 
>coordinates of the measurement spot. If you take 
>the coordinates of all your spots and import 
>them into a GIS program, you can get a map of 
>your points with the correct distances. Unless 
>you automatically probe/scan a straight line, 
>your path will have curves and bends and 
>ultimately be longer than the garnet diameter.
>
>This won't help you now, but should be useful 
>when planning future garnet probing.
>
>Best wishes,
>
>Jochen

Reia M. Chmielowski
Dipartimento di Scienze della Terra
Università degli Studi di Milano
Via Botticelli 23, 20133 Milano
phone +39 02503 15609
mobile phone +39 388 1199 386
fax +39 02503 15597
http://users.unimi.it/~spoli/thelab.html
http://unimi.academia.edu/ReiaChmielowski