----------------------------Original message---------------------------- To all of you wonderful people who helped: Thank you so much for the many responses to the question I posted about a formula for computing distance based on latitude/longitude. I've forwarded all of them to the person at ROCKWELL INTERNATIONAL CORP. in Cedar Rapids, IA who called me with his question. If he has any further questions, he will contact you directly. What would a Liberal Arts-type Map Collection Assistant do without you????? Jane Carlson Univ. of Iowa