Conversion between ECEF to local Geodetics datum

Could anybody please provide me a link or material to convert from ECEF to
local Geodetics datum (like East-North-Sky)? Better with plots. Any other
paper about datum conversion are also welcome.

Thank you!

You might want to look at
http://www.ngs.noaa.gov/PC_PROD/XYZWIN/

Johnson L wrote:



KBH wrote:

Here is some KBH code...just straight out of my files...for Delphi console
mode. And so the code will convert ECEF XYZ coordinates in meters to
latitude and longitude. Then the latitude and longitude can be
converted...with other programs...to UTM or to State Plane or to Local
Topocentric. (And I might have some Local Topocentric code but I don't post
my UTM code.)


Var
a: string;

Procedure Latlon;
Var
ra, lat, lon, x, y, z: double;
a, ee, v, h: double;
nr, ea, ht: double;
Begin
{KBH Code}
ra:= 180 / Pi;
a:= 6378137;
ee:= 0.006694379990;
WriteLn;
Write(' Input latitude in degrees: ');
ReadLn(lat);
Write(' Input longitude in degrees: ');
ReadLn(lon);
Write(' Input ellipsoidal height in meters: ');
ReadLn(h);
lat:= lat / ra;
lon:= lon / ra;
v:= a / Sqrt(1 - (ee * Sqr(Sin(lat))));
x:= (v + h) * Cos(lat) * Cos(lon);
y:= (v + h) * Cos(lat) * Sin(lon);
z:= ((1 - ee) * v + h) * Sin(lat);
WriteLn;
WriteLn(' x coordinate y coordinate z coordinate');
WriteLn;
WriteLn(x:18:3, y:18:3, z:18:3);
WriteLn;
{xyz to topocentric:}
{lat:= 45 / ra;
lon:= 0 / ra;}
lat:= 0;
lon:= 0;
nr:= (-x * Sin(lat) * Cos(lon)) + (-y * Sin(lat) * Sin(lon)) + (z *
Cos(lat));
ea:= (-x * Sin(lon)) + (y * Cos(lon));
ht:= (x * Cos(lat) * Cos(lon)) + (y * Cos(lat) * Sin(lon)) + (z * Sin(lat));
WriteLn(nr:18:3, ea:18:3, ht:18:3);
WriteLn;
End;

Procedure Xyzs;
Var
r, ra, lat, lon, x, y, z: double;
a, ee, f, p, u, la, lt, ha, hb, h, fm: double;
Begin
{KBH Code}
ra:= 180 / Pi;
a:= 6378137;
f:= 0.003352811;
fm:= 1 - f;
ee:= 0.006694379990;
WriteLn;
Write(' Input x coordinate in meters: ');
ReadLn(x);
Write(' Input y coordinate in meters: ');
ReadLn(y);
Write(' Input z coordinate in meters: ');
ReadLn(z);
If (x = 0) Then x:= 0.0001;
If (x < -a) Or (y < -a) Then Exit;}
p:= Sqrt(Sqr(x) + Sqr(y));
r:= Sqrt(Sqr(p) + Sqr(z));
u:= z / p * (fm + (ee * a / r));
u:= ArcTan(u);
lon:= ArcTan(y / x);
la:= (z * fm) + (ee * a * Sin(u) * Sqr(Sin(u)));
lt:= fm * (p - (ee * a * Cos(u) * Sqr(Cos(u))));
lat:= ArcTan(la / lt);
ha:= p * Cos(lat) + (z * Sin(lat));
hb:= a * Sqrt(1 - (ee * Sqr(Sin(lat))));
h:= ha - hb;
lon:= lon * ra;
lat:= lat * ra;
If (x < 0) Then lon:= 180 + lon;
WriteLn;
WriteLn(' Latitude Longitude');
WriteLn;
WriteLn(lat:18:6, lon:18:6, h:18:3);
WriteLn;
End;

Begin
{KBH Code}
WriteLn;
a:= 'lat';
While (a = 'lat') Or (a = 'xyz') Do
Begin
Write(' Enter "lat" for lat/lon to xyz or enter "xyz" for xyz to lat/lon:
');
ReadLn(a);
Begin
WriteLn;
WriteLn(' Program end: Hit [Enter]');
End;
If (a = 'lat') Then Latlon;
If (a = 'xyz') Then Xyzs;
End;
ReadLn;
End.


And those are ellipsoidal conversions...

I did a google search for my Local Topocentric code and found it at
sci.tech-archive.net:

{Latitude and longitude to ECEF xyz}
{KBH Code}
ra:= 180 / Pi;
a:= 6378137;
ee:= 0.006694379990;
Write(' Input latitude in degrees: ');
ReadLn(lat);
Write(' Input longitude in degrees: ');
ReadLn(lon);
Write(' Input ellipsoidal height in meters: ');
ReadLn(h);
lat:= lat / ra;
lon:= lon / ra;
v:= a / Sqrt(1 - (ee * Sqr(Sin(lat))));
x:= (v + h) * Cos(lat) * Cos(lon);
y:= (v + h) * Cos(lat) * Sin(lon);
z:= ((1 - ee) * v + h) * Sin(lat);


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


{ECEF xyz to local topocentric}
{KBH Code}
nr:= (-x * Sin(lat) * Cos(lon)) + (-y * Sin(lat) * Sin(lon)) + (z *
Cos(lat));
ea:= (-x * Sin(lon)) + (y * Cos(lon));
ht:= (x * Cos(lat) * Cos(lon)) + (y * Cos(lat) * Sin(lon)) + (z * Sin(lat));


{Note the first input is the lat and lon of the first xyz point converted to
local topocentric and then that lat and lon is held in the computations for
all the next xyz input points going to the same local topocentric system}


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


{ECEF xyz to latitude and longitude}
{KBH Code}
ra:= 180 / Pi;
a:= 6378137;
f:= 0.003352811;
fm:= 1 - f;
ee:= 0.006694379990;
WriteLn;
Write(' Input x coordinate in meters: ');
ReadLn(x);
Write(' Input y coordinate in meters: ');
ReadLn(y);
Write(' Input z coordinate in meters: ');
ReadLn(z);
If (x = 0) Then x:= 0.0001;
If (x < -a) Or (y < -a) Then Exit;}
p:= Sqrt(Sqr(x) + Sqr(y));
r:= Sqrt(Sqr(p) + Sqr(z));
u:= z / p * (fm + (ee * a / r));
u:= ArcTan(u);
lon:= ArcTan(y / x);
la:= (z * fm) + (ee * a * Sin(u) * Sqr(Sin(u)));
lt:= fm * (p - (ee * a * Cos(u) * Sqr(Cos(u))));
lat:= ArcTan(la / lt);
ha:= p * Cos(lat) + (z * Sin(lat));
hb:= a * Sqrt(1 - (ee * Sqr(Sin(lat))));
h:= ha - hb;
lon:= lon * ra;
lat:= lat * ra;
If (x < 0) Then lon:= 180 + lon;


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

Okay...I found a source that says that Topocentric Coordinates are often
called EHN (East North Height).