(meteorobs) OT- Map question.

Chris Peterson clp at alumni.caltech.edu
Thu Jan 1 14:27:11 EST 2009


Hi Larry-

Your questions have been answered elsewhere, so let me add something on a 
little different note. I don't know with what accuracy you are able to 
measure positions from your camera. Certainly, determining the position of a 
fireball explosion or a meteor in an individual frame to better than a 
degree is not difficult. Plotting that on a paper map, however, is difficult 
and likely to produce a significant error for a typical event 100 miles 
away. Even a conformal projection is unlikely to help all that much, since a 
conformal map is only exact for a specific latitude.

If your interest is to provide enough accuracy to aid in meteorite hunting, 
I'd suggest abandoning the paper map completely. Computer based map programs 
will allow you to accurately draw a line on a specific bearing, and will do 
so correctly, without regard to projection. I mostly use Garmin MapSource, 
which is a very inexpensive program.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message ----- 
From: "stange" <stange34 at sbcglobal.net>
To: <meteorobs at meteorobs.org>
Sent: Tuesday, December 30, 2008 1:19 PM
Subject: (meteorobs) OT- Map question.


>I have a 1965 raised relief map of California I use to estimate fireball
> explosion positions. It is a Nystrom "Lambert Conformal Conic Projection" 
> 1:
> 1,000,000.
>
> My question is how close are the Longitude lines in (alignment) to TRUE
> NORTH ?
>
> Latitude or elevation is not an issue. Thank you.
>
> (I have had varying answers from Nystrom, who suggested aligning the 
> map(?)
> with a compass, then rotate the map CCW 16 degrees ). There are no 
> magnetic
> declination reference marks on this map. Just latitude and longitude.
>
> Larry
> YCSentinel




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