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latitude and longitude fomat question

Old 12-12-2002, 06:36 AM
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Default latitude and longitude fomat question

on this site http://marinefisheries.org/ar/index.htm

They have latitude and longitude number in this format

2753.694 8251.177


can someone help me make sense of their format. What I assumed was way off from know point when I loaded it to my gps

Thanks
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Old 12-12-2002, 07:59 AM
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Default latitude and longitude fomat question

2753.694 8251.177

It looks to me like N27-53.694 by W82-51.177

I would think that would put the point near Winter Haven since my Lat/Lons are N25 and W80 from Key Largo.
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Old 12-12-2002, 08:01 AM
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Default latitude and longitude fomat question

What they are showing you is DDD MM.MMM which is to say degees, then minutes, then three decimal places of a minute. What they didn't do is seperate the degrees from the minutes.

So what you are seeing there is:

27 degrees 53.694 minutes Latitude (presumabley North) by 82 degrees 51.177 minutes (presumably west) Let's see, that would be somewhere in the gulf down around south florida wouldn't it (I'm at work with out a map within miles of me so i'm just guessing).

The other common formats are DDD.DDDD, DDD MM SS.S

The nice thing about the format you showed is that the last digit works out to be about 6 feet, just nice to keep in your head because it varies depending on location.

Thom

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Old 12-12-2002, 08:42 AM
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Default latitude and longitude fomat question

That is what I thought. I went back and looked again and in the spredsheet. To get it to my gps I was doing some math to convert to dd.ddddddd and I screwed up. Funny how far off you get when a "-" is where a "+" should have been


Thanks guys
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Old 12-12-2002, 09:21 AM
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Default latitude and longitude fomat question

Here is the text of an email, that I sent them about that very data a month ago (I used to work in the computer based mapping business, so I was asking about their conversion method etc).

My particular question was in reference to a software package called Arcview from ESRI, but the general description sheds more light on how they did things.

-=Andy


--- --- --- --- --- ---
We work with Arcview quite often to plot out these reefs coordinates, taht's amain reason it is in the format seen on teh web page. However we have no need to do a statewide map, so we do not have these all these coordinates re-formatted statewide into GIS format.

However, we do it regularly for given county and it is very easy to do in Excel with the existing data format.
What I do is set up an new column next to the LATITUDE and then another next to the LONGITUDE.

Next, I do a formula that divides the number of minutes by 60. It would look like this, for example 3023.234'N latitude would be: =(3023.234-3000)/60+30 and would return 30.38723. Of course in Excel you would put the cell number of say "N1" instead of the actual number of 3023.234. You can then cut and paste the entire column as long as the # of degrees stays the same (30 in this example). Make sure you copy and paste special "values" after this exercise to get rid of the formula.

Longitude is similar, except you need to multiply the result by -1, since Arcview needs a negative longitude (or it will plot off India somewhere).
Example 8645.234'W longitude would be: =[(8645.234-8600)/60+86]*-1. This would return -86.75390.
Hope this helps. I could send an example along if that would help.

-----------------

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