How does one calculate direction?

[Frederick Wilson]

Hello,

I have a table of known points. We have a course we send out managers
through. They pick several of the known points any any random order. I
would like to figure out how to get access to calculate the direction
from one point to the next.

I have searched google and other places but nothing that I have found
seems to work. depending which quadrant the easting and northing is in
will tell base direction but I can not get the compass direction.

Any ideas?

Thanks,
Fred

 

[Rob Oldfield]

Give us an example of the data you have in your table. What data type is
it?

 

[Frederick Wilson]

Point = Number as Double
Easting = Number as double
Northing = Number as double

 

[Rob Oldfield]

Minutes? Degrees? What is 'Point'?

Point = Number as Double
Easting = Number as double
Northing = Number as double

 

[Frederick Wilson]

OH Sorry. It is utm coordinate system. I am so sorry, guess I'm a little
slow.

Point (probably bad word to use), there are several known locations or
points.

So point 1 might be 5543 4756
point 2 5893 4322
point 3
point 4
..
..
..
Point 10 4972 5034

so how do I find the direction from point 10 to point 1

 

[Frederick Wilson]

I'm not normally that stingy. I do not have an excuse but I can give you
a reason, 2 kids, wife, dog, cat, 2 and half men.

 

[Dan Artuso]

some people are just stingy with the details

 

[Rob Oldfield]

Not having heard of the utm system before...is this the way that you're
using it...?

http://geology.isu.edu/geostac/Field_Exercise/topomaps/utm.htm

 

[Frederick Wilson]

yes

Not having heard of the utm system before...is this the way that you're
using it...?

http://geology.isu.edu/geostac/Field_Exercise/topomaps/utm.htm

 

[Rob Oldfield]

And that starts talking about which 'zone' you're in. Could you clarify how
that is recorded?

(Would "It's somewhere over there" be a good enough answer?)

 

[Fred Wilson]

And that starts talking about which 'zone' you're in. Could you clarify how
that is recorded?

(Would "It's somewhere over there" be a good enough answer?)



I

Okay. UTM is basically a metric grid system I guess it is very similar
to MGRS. One grid square is 1000 meters. You can find the distance
between two points by doing
sqrt(e1-e2 + n1-n2) where e=easting n=northing.

What I can not get worked out is the direction between two points.

 

[PC Datasheet]

Fred,

Please define quadrants. How many are there?

How do you tell what quadrant easting and northing are in?

Is there a 0,0 point?

 

[Frederick Wilson]

see now you are asking the questions where I start to get confused. I
know the grids count up as you move to the east/right and when you move
north/up.

 

[Paul Overway]

Are all the points in the same zone? If yes, and I'm understanding the
write up correctly, I believe you can determine direction comparing the
easting and northing values from one point to the next. So, if point 1
easting = x and point 2 easting > x...you're moving east. If point 2
easting < x you're moving west. Similarly comparison for
northing...whichever point has a higher number is farther north....which
should allow you to determine a general cardinal direction.

 

[PC Datasheet]

Frederick,

If we are going to help you, you need to answer our questions instead of
being evasive! I asked three questions and you did not answer any of them.

Are these statements fair to say ?

If easting Point 1 < easting Point 2 AND northing Point 1 = northing Point
2, you have moved due West?

If northing Point 1 < northing Point 2 AND easting Point 1 = easting Point
2, you have moved due North?

Another question ---
Is moving 10 units easting the same distance as moving 10 units northing?

--
PC Datasheet
Your Resource For Help With Access, Excel And Word Applications
(e-mail address removed)
www.pcdatasheet.com

 

[Rob Oldfield]

Are all the points in the same zone?

That definitely needs an answer. What result are you actually after
Frederick? A bearing (i.e. 0-360 degrees)? Or just, as Paul is talking
about, a cardinal direction.

 

[Fred Wilson]

I am REALLY not trying to be evasive I REALLY don't understand. I am
trying and I appreciate your patients.

Okay, 360 degrees are in effect. Cardinal headings are not good enough.
Northing and easting are the same measurements.

If anyone has been in the military it is just like using a military map,
compass and know points through the woods from point a to point b,
then to c and so on.

I did find some information from an aviation page but it is talking
about the great circle rule which applies to distances WAY bigger than I
am speaking of.

northing 'a' can be < or > or = northing 'b'
easting 'a' can be < or > or = easting 'b'

and any combination thereof.


Once again, thanks for your patients.

 

[PC Datasheet]

To get the direction you need to check these conditions:
1. northing 1 = northing 2, direction = due east or due west depending on
easting 1 and easting 2
2. northing 1 < northing 2, direction = north by east or north by west
depending on easting 1 and easting 2
3. northing 1 > northing 2, direction = south by east or south by west
depending on easting 1 and easting 2
4. easting 1 < easting 2, direction is easterly
5. easting 1 > easting 2, direction is westerly

To get the angle of travel (Xdegrees, Yminutes, Zseconds):
Calculate: Tangent of angle = (northing 1 - northing 2)/(easting 1 -
easting 2)


--
PC Datasheet
Your Resource For Help With Access, Excel And Word Applications
(e-mail address removed)
www.pcdatasheet.com

 

[Rob Oldfield]

....and the arctangent function in Access is called atn.

 

[Frederick Wilson]

I found this formula

=atan2((e1-e2),(n1-n2))*180/PI()
e= easting
n=northing

It seems to work in Excel Kind of. I say this because it appears to give
the direction 180 degrees out.

Additionally, atan2 is not a function in Access and because I do not
know what this formula is doing I am not sure how to work around it.

Any ideas?