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Help with NGS descriptions

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I've noticed that some data sheet use some text in their descriptions that I'm not sure what it means. An example can be found on this sheet, AA6775 at http://www.geocaching.com/mark/details.aspx?PID=AA6775

 

I've highlighted the text I'm trying to figure out in RED:

CENTERLINE OF SHELDON ROAD IS N 90 E, 33.30 FEET, CENTERLINE OF FIVE MILE ROAD IS N 0 W, 132.91 FEET, A POWER POLE LIES N 20 W, 79.31 FEET, THE NORTHEAST CORNER OF A SIGN BASE LIES S 45 W, 37.11 FEET.

 

Thanks

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I've noticed that some data sheet use some text in their descriptions that I'm not sure what it means. An example can be found on this sheet, AA6775 at http://www.geocaching.com/mark/details.aspx?PID=AA6775

 

I've highlighted the text I'm trying to figure out in RED:

CENTERLINE OF SHELDON ROAD IS N 90 E, 33.30 FEET, CENTERLINE OF FIVE MILE ROAD IS N 0 W, 132.91 FEET, A POWER POLE LIES N 20 W, 79.31 FEET, THE NORTHEAST CORNER OF A SIGN BASE LIES S 45 W, 37.11 FEET.

 

Thanks

The short answer is that directions are being given either starting from the north or the south. The idea is tho keep the bearing (i.e. direction) to 90 degrees or less.

 

The way it works is the first letter is the starting direction, either N (=north) or S (=south). The other letter is the direction you turn towards. It will either be E (=east) or W (=west). The number between the two letters is how far to turn in degrees.

 

Example: N 45 E means start by facing north and turn 45 degrees towards the east. We would simple call that northeast.

 

Example: S 60 W means start by facing south and turn 60 degrees towards the west. That is a little past southwest.

 

If you use the system we usually follow (generally called the "azimuth" - such as when we use a compass or GPS) we would say

 

N 45 E = an azimuth of 45 degrees

 

S 60 W = an azimuth of 240 degrees.

 

I will leave it as an exercise to convert the numbers given in your example to azimuth. But I would say the ones "N 90 E" and "N 0 W" are rather pedantic to say the least. Why not just say "East" for the first and "North" for the second. Oh well, maybe it was a summer intern who had to write it up :laughing:

 

Just watch out for one thing: occasionally numbers will use magnetic north (or south) rather than true north (or south). This is rare but it can happen. The general rule is if it doesn't say anything, then it's true north (or south) they're using. It will only be magnetic if it says so.

Edited by Papa-Bear-NYC

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I've noticed that some data sheet use some text in their descriptions that I'm not sure what it means. An example can be found on this sheet, AA6775 at http://www.geocaching.com/mark/details.aspx?PID=AA6775

 

I've highlighted the text I'm trying to figure out in RED:

CENTERLINE OF SHELDON ROAD IS N 90 E, 33.30 FEET, CENTERLINE OF FIVE MILE ROAD IS N 0 W, 132.91 FEET, A POWER POLE LIES N 20 W, 79.31 FEET, THE NORTHEAST CORNER OF A SIGN BASE LIES S 45 W, 37.11 FEET.

 

Thanks

 

The measurements appear to be FROM the mark to the respective landmarks.

 

N 90 E is the direction 90 deg east of North, which is an azimuth of 90 deg, due East

 

N 0 W is 0 deg West from North. which is an azimuth of 0 deg, due North

 

N 20 W is 20 deg west from north which is an azimuth of 340 deg

 

S 45 W is 45 deg West from South, which is an azimuth of 225 deg.

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Introduction to Compass Bearings

 

N 90 E - reads North, 90 degrees east (of) or just plain East

N 0 W - reads North 0 degree west or just plain North

N 20 W - reads North, 20 degrees west (of)

S 45 W - reads South, 45 degrees west (of)

 

Image10588.gif

Edited by Z15

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