Geodetic Toolbox

Toolbox for angle, coordinate and date conversions and transformations. Version 2.92a.

Description

A collection of geodetic functions that solve a variety of problems in geodesy. Supports a wide range of common and user-defined reference ellipsoids. Most functions are vectorized. Functions include:

Angle Conversions
  deg2rad - Degrees to radians
  dms2deg - Degrees,minutes,seconds to degrees
  dms2rad - Degrees,minutes,seconds to radians
  rad2deg - Radians to degrees
  rad2dms - Radians to degrees,minutes,seconds
  rad2sec - Radians to seconds
  sec2rad - Seconds to radians
 
Coordinate Conversions
  ell2utm - Ellipsoidal (lat,long) to UTM (N,E) coordinates
  ell2xyz - Ellipsoidal (lat,long) to Cartesian (x,y,z) coodinates
  sph2xyz - Shperical (az,va,dist) to Cartesian (x,y,z) coordinates
  xyz2sph - Cartesian (x,y,z) to spherical (az,va,dist) coordinates
  xyz2ell - Cartesian (x,y,z) to ellipsoidal (lat,long,ht) coordinates
  xyz2ell2 - xyz2ell with Bowring height formula
  xyz2ell3 - xyz2ell using complete Bowring version
 
Coordinate Transformations
  refell - Reference ellipsoid definition
  ellradii - Various radii of curvature
  cct2clg - Conventional terrestrial to local geodetic cov. matrix
  clg2cct - Local geodetic to conventional terrestrial cov. matrix
  ct2lg - Conventional terrestrial (ECEF) to local geodetic (NEU)
  dg2lg - Differences in Geodetic (lat,lon) to local geodetic (NEU)
  lg2ct - Local geodetic (NEU) to conventional terrestrial (ECEF)
  lg2dg - Local geodetic (NEU) to differences in geodetic (lat,lon)
  direct - Direct geodetic problem (X1,Y1,Z1 + Az,VA,Dist to X2,Y2,Z2)
  inverse - Inverse geodetic problem (X1,Y1,Z1 + X2,Y2,Z2 to Az,VA,Dist)
  simil - Similarity transformation (translation,rotation,scale change)
 
Date Conversions
  cal2jd - Calendar date to Julian date
  dates - Converts between different date formats
  doy2jd - Year and day of year to Julian date
  gps2jd - GPS week & seconds of week to Julian date
  jd2cal - Julian date to calenar date
  jd2dow - Julian date to day of week
  jd2doy - Julian date to year & day of year
  jd2gps - Julian date to GPS week & seconds of week
  jd2yr - Julian date to year & decimal year
  yr2jd - Year & decimal year to Julian date
 
Error Ellipses
  errell2 - Computes error ellipse semi-axes and azimuth
  errell3 - Computes error ellipsoid semi-axes, azimuths, inclinations
  plterrel - Plots error ellipse for covariance matrix
 
Miscellaneous
  findfixed - Finds fixed station based on 3D covariance matrix
  pltnet - Plots network of points with labels
 
Example Scripts
  DirInv - Simple partial GUI script for direct and inverse problems
  DirProb - Example of direct problem
  Dist3D - Example to compute incremental 3D distances between points.
  InvProb - Example of inverse problem
  PltNetEl - Example plot of network error ellipses
  ToUTM - Example of conversion from latitude,longitude to UTM

Most recent version can be found at <ftp://geod.nrcan.gc.ca/pub/GSD/craymer/software/matlab/geodetic/>.

• Acknowledgements: This submission has inspired the following:; Equinoxes and Solstices
• MATLAB release: MATLAB 7.0.4 (R14SP2)

Other Files

geodetic/.DS_Store,
geodetic/cal2jd.m,
geodetic/cct2clg.m,
geodetic/clg2cct.m,
geodetic/Contents.m,
geodetic/ct2lg.m,
geodetic/dates.m,
geodetic/dates_old.m,
geodetic/deg2rad.m,
geodetic/dg2lg.m,
geodetic/direct.m,
geodetic/DirInv.m,
geodetic/DirProb.m,
geodetic/Dist3D.m,
geodetic/dms2deg.m,
geodetic/dms2rad.m,
geodetic/doy2jd.m,
geodetic/ell2utm.m,
geodetic/ell2xyz.m,
geodetic/ellradii.m,
geodetic/errell2.m,
geodetic/errell3.m,
geodetic/findfixed.m,
geodetic/gps2jd.m,
geodetic/inverse.m,
geodetic/InvProb.m,
geodetic/jd2cal.m,
geodetic/jd2dow.m,
geodetic/jd2doy.m,
geodetic/jd2gps.m,
geodetic/jd2yr.m,
geodetic/lg2ct.m,
geodetic/lg2dg.m,
geodetic/plterrel.m,
geodetic/pltmap.m,
geodetic/pltnet.m,
geodetic/PltNetEl.m,
geodetic/rad2deg.m,
geodetic/rad2dms.m,
geodetic/rad2sec.m,
geodetic/refell.m,
geodetic/rotct2lg.m,
geodetic/rotlg2ct.m,
geodetic/sec2rad.m,
geodetic/simil.m,
geodetic/sph2xyz.m,
geodetic/ToUTM.m,
geodetic/txyz2ell.m,
geodetic/xyz2ell.m,
geodetic/xyz2ell2.m,
geodetic/xyz2ell3.m,
geodetic/xyz2sph.m,
geodetic/yr2jd.m,
license.txt

[John D'Errico]

This seems pretty good from what I checked. There are many conversions in here.

A couple of minor points. I notice that there is no error checking. For example, in ellradii one must provide an axis length and eccentricity (squared). But there are no checks on the proper number of parameters or even on the sign of the eccentricity.

In dms2deg, I noticed one interesting feature. Converting from 32 degrees, 12 minutes, -3 seconds, results in a degree prediction of:

dms2deg([32 12 -3])
ans =
      -32.201

Overall, its still pretty good.

[Nice Work]

Nice work

[Ali Ebrahimi]

 

[Jagkrich A.warangkul]

Thanks

[Ray Borough]

Very Useful

[Gene Newton]

Thank you.

[jaime torres]

gracias

[Christopher]

under matlab which file do i put this in so that it is being used?

[Sebastian Hölz]

There is a potential bug in function ell2UTM, which may lead to wrong results in the calculated northing, if the funciton is called with a vector containing coordinates from both southern and northern hemisphere. Change lines 23-27, which read ...

if lat>=0
  No=0;
else
  No=10000000;
end

to ...

No(size(lat))=0; % False northing (north)
No(lat<0) = 1e7; % False northing (south)

Sebastian

[Mike Craymer]

I corrected the bug for vector and array input to function ell2utm per Sebastian Holz's comments and posted a new version 2.91. Unfortunately, the fix only worked for row vectors. I've corrected it again in version 2.92 and tested it this time to make sure it works. Sorry for any problems this may have caused. In addition to error checking, I'll consider adding array input to all functions in the next major release (this Summer I hope).

[Sepideh]

Thanks for that, very useful

[Jonathan]

Hello,

Thank you for such a useful toolbox! I have a question, however, regarding transforming lat,lon on the WGS84 ellipsoid to local North East Up. If I use the same lat,lon coordinate as both my point to convert and my origin, why would I get a -21.5 km local North value? Shouldn't North and East both be zero?

Thanks again,
Jon

<SNIP>

>> [a,b,e2,finv] = refell('WGS84'); %get ellipsoid params
rlat = deg2rad(40); rlon = deg2rad(-108); %lat,lon
[Xec Yec Zec] = ell2xyz(rlat,rlon,0,a,e2) %convert to ECEF xyz
[N E Up] = ct2lg(Xec,Yec,Zec,rlat,rlon) %convert to local NEU

Xec =
  -1.5119e+06
Yec =
  -4.6532e+06
Zec =
   4.0780e+06

N =
  -2.1054e+04
E =
     0
Up =
   6.3693e+06

</SNIP>

[Mike Craymer]

Dear Jonathon,

I just saw your question about transforming lat,lon to N,E,U. The ct2lg function in your last step requires as input the X,Y,Z coordinate *differences* between the two points. In your example, you entered the X,Y,Z coordinates for just one point. ct2lg would have interpreted this as very large X,Y,Z coordinate differences. The correct conversion for your example is given below (you need to enter the X,Y,Z differences in ct2lg as Xec-Xec, Yec-Yec, Zec-Zec).

Thanks for your comments!
-Mike

>> [a,b,e2,finv] = refell('WGS84'); %get ellipsoid params
rlat = deg2rad(40); rlon = deg2rad(-108); %lat,lon
[Xec Yec Zec] = ell2xyz(rlat,rlon,0,a,e2) %convert to ECEF xyz
[N E Up] = ct2lg(Xec-Xec,Yec-Yec,Zec-Zec,rlat,rlon) %convert to local NEU

Xec =

  -1.5119e+06

Yec =

  -4.6532e+06

Zec =

   4.0780e+06

N =

     0

E =

     0

Up =

     0