Hi Laurent,

Those columns give the "level of importance" (LOI) of a city
(1=major international metropolis to 7=very small town), and
the three-digit country identifier. For details:

http://www.projectpluto.com/random.htm#city_format

You can modify them in the manner you suggest without any
great risk. Making the LOI into a tenths-of-arcminute field
means that the "city" in question may become more or less
"important", which would cause it to be more or less likely
to appear on the chart. (Guide draws the most "important"
cities first; less "important" cities may not have room for
their labels to be shown.) The country field isn't currently
used for anything at all.

Your comments about the problems with different longitude
formats are well-taken. I've revised the program to work
"logically": you can always enter + or - for latitudes,
since there is no "south is positive" convention to confuse
us. If you've selected display of lat/lon with compass
letters (in the increasingly misnamed RA/Dec Format
dialog), you can't enter + or - for longitudes, because Guide
can't figure out if positive is east or west (both conventions
get roughly equal use).

If you do select +/- for longitude display, with either the
"E positive" or "W positive" convention, then Guide will
accept longitude "compass signs" of E, W, +, or -,
with the last two interpreted depending on whether
you selected "E positive" or "W positive". Confusing to
describe, perhaps, but it should be passably intuitive
to use.

-- Bill