Derive latitude/longitude from integer values

I'm a software developer hired to work on a GIS application. My client
has an Access database they purchased a long time ago from some website
that no one remembers. The database contains a list of cities along
with their coordinates (latitude/longitude). I have to process the
coordinates as latitudes and longitudes, but the database has stored
them as signed integers (not decimals). I can't figure out the
conversion from integer to degress/minutes/seconds and was hoping
someone here can help me.

Here is some of the sample data:
(The 'ACTUAL' values displayed below are from a sample application that
shipped with the data, but we don't have the source code for it).

Austin, TX
ACTUAL: 30 17N, 97 44W
STORED IN DB: 3028, -9773

Berkeley, CA
ACTUAL: 37 52N, 122 16W
STORED IN DB: 3787, -12227

Birmingham, AL
ACTUAL: 33 31N, 86 48W
STORED IN DB: 3352, -8680

As you can see, the data provider seems to have encoded the degrees as
is (e.g. 30, 37, 97, 122). What I don't get is how you calculate the
minutes/seconds from the integer. For example, in Austin, TX above, how
do you figure 17 minutes (latitude) from 3028?

If any math wiz can figure out the pattern here, I'd greatly appreciate
it. Thanks!

On 30 Jun 2005 13:06:07 -0700, turntableguy@gmail.com wrote:



It looks like the "integer" values are actually fixed-point values,
with an implied decimal point before the rightmost two digits.



--
Chuck Taylor
http://home.hiwaay.net/~taylorc/contact/

turntableguy@gmail.com wrote:

No problem :)

The key is that there are 60 minutes to a degree...

So Austin, TX, above was actually 30 17N and 3028 in the database.

You have already figured that the first two digits from the database is
the number of degrees, 30 in this example.

The next part is 17 minutes, which is 17 minutes divided by 60 minutes
per degree eqauls 0.28 degrees, hence 3028 in he database.

Going the other way you take -9773 which makes W (think of a coordinate
system where W is to the left of the axis making values negative) 97
degrees 73 multiplied by 0.6 equals 44 minutes: 97 44W

So N and E are represented as positive values in the database, while S
and W are negative values in the database.

Hope this helped.

/Mogens

Mogens Beltoft wrote:

I think more accurately the last two digits are the decimal degrees, e.g
the value -12227 represents -122.27.

Walter

turntableguy@gmail.com wrote:

There are 60 minutes per degree, so in .28 degrees there are 17 minutes
(0.28 * 60).