----------------------------Original message---------------------------- A patron asked me the meaning of a symbol on a provisional edition of a topo sheet, and I didn't recognize it. It looks like "crosshairs," i.e., a circle divided in four, and it occurs in various places on the map. Next to each one is a hyphenated group of numerals, such as 1-112, 2-27, etc. My guess is that it has to do with the sequence of aerial photos used for surveying the area, and that they'll gone if the sheet is published in its final form. Is this correct? -- KR Ken Rockwell "Just another map librarian" at Marriott Library University of Utah Salt Lake City, Utah "Without Geography--you're NOWHERE!"