Bookmark this page:
If you were Registered and logged in, you could reply and use other advanced thread options
All, I've been charged with the task of generating a grid covering
certain states where each grid is X square miles.
To do this I need to take a point x1,y1 and add X mile(s) E/W and X
mile(s) N/S. Does anyone out there have a function that will accept a
point in lat/lon, a distance in miles, and a direction (N/S/E/W) only
and return a lat/lon of the new point?
tia,
CG
certain states where each grid is X square miles.
To do this I need to take a point x1,y1 and add X mile(s) E/W and X
mile(s) N/S. Does anyone out there have a function that will accept a
point in lat/lon, a distance in miles, and a direction (N/S/E/W) only
and return a lat/lon of the new point?
tia,
CG
http://williams.best.vwh.net/avform.htm#LL
Watch out, since ALL parameters need to be radians - also your X miles.
tc is the true course: 0, pi/2, pi and 3*pi/2 for the 4 directions.
Watch out, since ALL parameters need to be radians - also your X miles.
tc is the true course: 0, pi/2, pi and 3*pi/2 for the 4 directions.
What do you really want to do? It's not possible to overlay a square
grid on the surface of a sphere. Imagine trying to glue a piece of
plane graph paper onto a sphere. Somewhere it will develop creases, or
it will have to be stretched.
Many mid-western states have roads laid out on "section lines". Each
section encloses one square mile. The E-W roads run along parallels.
The N-S ones take periodic jogs. Without them, the sections would get
smaller in width as you went North.
The resulting sections are all (approximately one mile square, but
you'd need a loose definition of "grid" to describe the roads as such.
If a grid with curved sides is acceptable, lay out a square grid on
an equal area projection of the sphere (of which there are several) and
project back onto the sphere.
crgiles@gmail.com wrote:
grid on the surface of a sphere. Imagine trying to glue a piece of
plane graph paper onto a sphere. Somewhere it will develop creases, or
it will have to be stretched.
Many mid-western states have roads laid out on "section lines". Each
section encloses one square mile. The E-W roads run along parallels.
The N-S ones take periodic jogs. Without them, the sections would get
smaller in width as you went North.
The resulting sections are all (approximately one mile square, but
you'd need a loose definition of "grid" to describe the roads as such.
If a grid with curved sides is acceptable, lay out a square grid on
an equal area projection of the sphere (of which there are several) and
project back onto the sphere.
crgiles@gmail.com wrote:
> All, I've been charged with the task of generating a grid covering
> certain states where each grid is X square miles.
> To do this I need to take a point x1,y1 and add X mile(s) E/W and X
> mile(s) N/S. Does anyone out there have a function that will accept a
> point in lat/lon, a distance in miles, and a direction (N/S/E/W) only
> and return a lat/lon of the new point?
>
> tia,
>
> CG
> certain states where each grid is X square miles.
> To do this I need to take a point x1,y1 and add X mile(s) E/W and X
> mile(s) N/S. Does anyone out there have a function that will accept a
> point in lat/lon, a distance in miles, and a direction (N/S/E/W) only
> and return a lat/lon of the new point?
>
> tia,
>
> CG
- eTrex Vista HCx -- gray grid lines!
- Garmin GPS
- 2009-11-19
- Satnav that accepts input in UK BNG (Ordnance Survey) Grid reference ++INSIDE
- UK GPS Discussions
- 2009-12-16
- Rocanda Grid Map
- Garmin GPS
- 2009-06-22
- Calculating a coordinate?
- Satellite Navigation
- 2006-09-29
- UK in car sat-nav devices - navigate to OS grid reference point? (answer: yes!)
- UK GPS Discussions
- 2007-08-14
> certain states where each grid is X square miles.
> To do this I need to take a point x1,y1 and add X mile(s) E/W and X
> mile(s) N/S. Does anyone out there have a function that will accept a
> point in lat/lon, a distance in miles, and a direction (N/S/E/W) only
> and return a lat/lon of the new point?
> tia,
> CG