Radar Plot using geographical coordinates

[David]

I am trying to generate a circular radar or XY scatter point plot using
geographical coordinates referenced to a tower in the aproximate center
(with its own geographical coordinates and the plotted data in 4 quadrants
(+X/+Y, -X/+Y, -X/-Y and +X/-Y) in order to plot the RF field strength of an
FM broadcast station.

I have 5 columns of data:
1 the Latitude coordinates of the tower for center reference.
2 the Longitude coordinates of the tower for center reference.
3 the Latitude coordinates where I took the measurements.
4 the Longitude coordinates where I took the measurements.
5 The RF field strength at the aforementioned coordinates .

I would really appreciate any help with this as it has been quite a few
decades since I have tried Cartisian Co-ordinates, or rectangular to polar
conversions and such. What's left of my brain is starting to get foggy!!!

Dave Whitehead
(e-mail address removed)

 

[Barb R.]

Try this
http://www.teacherschoice.com.au/Maths_Library/Coordinates/polar_-_rectangular_conversion.htm

 

[Tushar Mehta]

I am not sure you need to convert between polar and cartesian
coordinates. When looking at latitude and longitude lines over a small
enough region, the lines will form a rectangular grid. [It is only
when looking at a large enough region of the earth that the convergence
of the longitude lines becomes apparent.]

So, if the region of interest is sufficiently small, all you need to do
is subtract each latitude (y) and longitude (x) from the tower's
lat/long readings. Now, plot these relative x,y readings and you will
have a map of the various positions where you took the readings with
the tower being at the center at (0,0).

Use Bovey's XY Chartlabeler (www.appspro.com) or Walkenbach's Chart
Tools (www.j-walk.com) to add the RF field strength as a data label for
each plotted point.

--
Regards,

Tushar Mehta
www.tushar-mehta.com
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