[Xastir] Re: USGS DRG files no longer free.. (Tyler Allison)

[Tyler Allison]

> On Mon, 6 Oct 2003, Tyler Allison wrote:
>
>> Yes I know that part...but how do I get -121.000000 (or 121.0W) from
>> this:
>>
>> >> Upper Left    ( 632249.045,5382177.092)  (121d12'24.93"W,
>> 48d34'50.46"N)
>> >> Lower Left    ( 632249.045,5305885.652)  (121d13'50.68"W,
>> 47d53'40.68"N)
>> >> Upper Right   ( 739487.845,5382177.092)  (119d45'17.40"W,
>> 48d32'56.01"N)
>> >> Lower Right   ( 739487.845,5305885.652)  (119d47'52.37"W,
>> 47d51'48.94"N)
>> >> Center        ( 685868.445,5344031.372)  (120d29'50.79"W,
>> 48d13'27.20"N)
>>
>> Can I simply round 121d12'24.93W to 121W and call it a day?  That doesnt
>> sound very accurate or correct.
>
> Nope.
>
> Bring up Xastir's Coordinate Calculator.
>
> Type in "48 34 50.46N" and "121 12 24.93W".  Press Calculate.
>
> You should see:
>
>     "Decimal Degrees: 48.58068N  121.20692W"
>
> as the first line in the output.

True. That's what I get.

Im not trying to be a tard really. I just dont see how 121.20692W turns
into -121. Shouldnt the line be -121.20692 or can you simply drop the
decimal section when building a fdg file from hand?

Am I thinking too hard? ;)

On to the next question:

How do I know which number to use as the east/south/west/north boundaries?
The listgeo file has two numbers listed for things like 'lower left' or
'upper right' which obviously isnt east or south ;)

Right now Im just sorta looking at the 'working' geotif files and saying...

Well the second number on the third line of that listgeo was a 121 and the
fdg for east boundary is 121 so I must need to take the third line of my
listgeo output and make it my east boundary.  I have no idea what it all
means Im just faking it ;)  I'd prefer to understand what Im doing instead
of "take the third number, drop the decimal and make it the East boundary"

-Tyler