### EGM Coefficient Data (Example)

Source: https://github.com/tomojitakasu/rtklib/blob/master/lib/iers/src/gpt.f.org

Example data for AT_AMP coefficients, used in surface temperature calculations. These are typically part of a larger dataset.

```fortran
     .+0.0000D+000,-4.5415D-002,-1.8027D-002,+3.6561D-004,-1.1274D-004,
     .+1.3047D-005,+2.0001D-006,-1.5152D-007,-2.7807D-008,+7.7491D-009/
```

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

### EGM Coefficient Data (Example)

Source: https://github.com/tomojitakasu/rtklib/blob/master/lib/iers/src/gpt.f.org

Example data for BT_AMP coefficients, used in surface temperature calculations. These are typically part of a larger dataset.

```fortran
      DATA (BT_AMP(I),I=1,55)/ 
     .+0.0000D+000,+0.0000D+000,-8.9895D-001,+0.0000D+000,-1.0790D+000,
     .-1.2699D-001,+0.0000D+000,-5.9033D-001,+3.4865D-002,-3.2614D-002,
     .+0.0000D+000,-2.4310D-002,+1.5607D-002,-2.9833D-002,-5.9048D-003,
     .+0.0000D+000,+2.8383D-001,+4.0509D-002,-1.8834D-002,-1.2654D-003,
     .-1.3794D-004,+0.0000D+000,+1.3306D-001,+3.4960D-002,-3.6799D-003,
     .-3.5626D-004,+1.4814D-004,+3.7932D-006,+0.0000D+000,+2.0801D-001,
     .+6.5640D-003,-3.4893D-003,-2.7395D-004,+7.4296D-005,-7.9927D-006,
     .-1.0277D-006,+0.0000D+000,+3.6515D-002,-7.4319D-003,-6.2873D-004,
     .-8.2461D-005,+3.1095D-005,-5.3860D-007,-1.2055D-007,-1.1517D-007,
     .+0.0000D+000,+3.1404D-002,+1.5580D-002,-1.1428D-003,+3.3529D-005,
     .+1.0387D-005,-1.9378D-006,-2.7327D-007,+7.5833D-009,-9.2323D-009/
```

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

### EGM Coefficient Data (Example)

Source: https://github.com/tomojitakasu/rtklib/blob/master/lib/iers/src/gpt.f.org

Example data for AT_MEAN coefficients, used in surface temperature calculations. These are typically part of a larger dataset.

```fortran
      DATA (AT_AMP(I),I=1,55)/
     .-1.8654D+000,-9.0041D+000,-1.2974D-001,-3.6053D+000,+2.0284D-002,
     .+2.1872D-001,-1.3015D+000,+4.0355D-001,+2.2216D-001,-4.0605D-003,
     .+1.9623D+000,+4.2887D-001,+2.1437D-001,-1.0061D-002,-1.1368D-003,
     .-6.9235D-002,+5.6758D-001,+1.1917D-001,-7.0765D-003,+3.0017D-004,
     .+3.0601D-004,+1.6559D+000,+2.0722D-001,+6.0013D-002,+1.7023D-004,
     .-9.2424D-004,+1.1269D-005,-6.9911D-006,-2.0886D+000,-6.7879D-002,
     .-8.5922D-004,-1.6087D-003,-4.5549D-005,+3.3178D-005,-6.1715D-006,
     .-1.4446D-006,-3.7210D-001,+1.5775D-001,-1.7827D-003,-4.4396D-004,
     .+2.2844D-004,-1.1215D-005,-2.1120D-006,-9.6421D-007,-1.4170D-008,
     .+7.8720D-001,-4.4238D-002,-1.5120D-003,-9.4119D-004,+4.0645D-006,
     .-4.9253D-006,-1.8656D-006,-4.0736D-007,-4.9594D-008,+1.6134D-009/
```

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

### Initialize Google Earth Instance

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Debug_Build/rtkplot_ge.htm

Initializes the Google Earth plugin instance and sets up initial options and event handlers.

```javascript
var ge = null;
var mark1,mark2,track1,track2,points,altmode;
var mark_icon1="http://maps.google.com/mapfiles/kml/paddle/ylw-circle.png";
var mark_icon2="http://maps.google.com/mapfiles/kml/paddle/red-circle.png";
var mark_icon3="http://maps.google.com/mapfiles/kml/paddle/wht-circle.png";

function init() {
    google.earth.createInstance("map3d",initCallback,failureCallback);
}

function initCallback(instance) {
    ge = instance;
    var opt = ge.getOptions();
    opt.setFlyToSpeed(ge.SPEED_TELEPORT);
    opt.setAtmosphereVisibility(false);
    opt.setMouseNavigationEnabled(true);
    opt.setBuildingSelectionEnabled(false);
    opt.setAutoGroundLevelViewEnabled(false);
    mark1 = GenMark('1',mark_icon1);
    mark2 = GenMark('2',mark_icon2);
    track1 = GenLine('track1','cc00ffff');
    track2 = GenLine('track2','cc0044ff');
    points = new Array();
    altmode = ge.ALTITUDE_CLAMP_TO_GROUND;
    ge.getWindow().setVisibility(true);
    document.getElementById('state').value='1';
    setInterval("UpdateState()",250);
}

function failureCallback(errcode) {
    document.write('<P align=center>Google Earth Plugin load error</P>');
    document.getElementById('state').value='-1';
}
```

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

### Initialize Google Earth API

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Debug_Build/rtkplot_ge.htm

Loads the Google Earth API version 1 and sets up the callback function 'init' to be executed once the API is ready.

```javascript
google.load("earth","1");
google.setOnLoadCallback(init);
```

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

### Initialize Google Earth Plugin

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Release_Build/rtkplot_ge.htm

Initializes the Google Earth plugin instance and sets up basic options. This function should be called on page load.

```javascript
var ge = null;
var mark1,mark2,track1,track2,points,altmode;
var mark_icon1="http://maps.google.com/mapfiles/kml/paddle/ylw-circle.png";
var mark_icon2="http://maps.google.com/mapfiles/kml/paddle/red-circle.png";
var mark_icon3="http://maps.google.com/mapfiles/kml/paddle/wht-circle.png";

function init() {
    google.earth.createInstance("map3d",initCallback,failureCallback);
}

function initCallback(instance) {
    ge = instance;
    var opt = ge.getOptions();
    opt.setFlyToSpeed(ge.SPEED_TELEPORT);
    opt.setAtmosphereVisibility(false);
    opt.setMouseNavigationEnabled(true);
    opt.setBuildingSelectionEnabled(false);
    opt.setAutoGroundLevelViewEnabled(false);

    mark1 = GenMark('1',mark_icon1);
    mark2 = GenMark('2',mark_icon2);
    track1 = GenLine('track1','cc00ffff');
    track2 = GenLine('track2','cc0044ff');
    points = new Array();
    altmode = ge.ALTITUDE_CLAMP_TO_GROUND;

    ge.getWindow().setVisibility(true);
    document.getElementById('state').value='1';
    setInterval("UpdateState()",250);
}

function failureCallback(errcode) {
    document.write('<P align=center>Google Earth Plugin load error</P>');
    document.getElementById('state').value='-1';
}
```

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

### Initialize Google Map

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Release_Build/rtkplot_gm.htm

Initializes the Google Map with specified options including center, zoom level, and map type. Requires a div with id 'map' to exist.

```javascript
var map = null;
var marks = [];
var markh = null;
var markz = 0;
var info = null;
var icon0="http://maps.google.co.jp/mapfiles/ms/icons/red-dot.png";
var icon1="http://maps.google.co.jp/mapfiles/ms/icons/yellow-dot.png";

function init() {
    var opt = {
        center: new google.maps.LatLng(0,0),
        zoom: 2,
        minZoom: 2,
        streetViewControl: false,
        mapTypeId: google.maps.MapTypeId.ROADMAP
    };
    map = new google.maps.Map(document.getElementById("map"),opt);
    document.getElementById('state').value='1';
}
```

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

### Show All Points in Google Earth

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Release_Build/rtkplot_ge.htm

Iterates through all points and sets their visibility to 1 (visible). Requires the 'ge' object to be initialized.

```javascript
function ShowPoint() {
 if (ge == null) return;
 for (var i = 0; i < points.length; i++) {
  var mark = points[i];
  mark.setVisibility(1);
 }
}
```

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

### Show Points

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Debug_Build/rtkplot_ge.htm

Makes all added points visible in the Google Earth view.

```javascript
function ShowPoint() {
    if (ge == null) return;
    for (var i = 0; i < po
```

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

### Show All Points in Google Earth

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Debug_Build/rtkplot_ge.htm

Iterates through a collection of points and sets their visibility to 1 (visible). Assumes 'points' array and 'ge' object are defined.

```javascript
function ShowPoint() {
  if (ge == null) return;
  for (var i = 0; i < points.length; i++) {
    var mark = points[i];
    mark.setVisibility(1);
  }
}
```

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

### Set Google Earth Options

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Debug_Build/rtkplot_ge.htm

Configures various Google Earth viewer options like navigation controls, scale legend, overview map, grid, status bar, and layers.

```javascript
function SetOpts(f1,f2,f3,f4,f5,f6,f7,f8,f9,f10) {
    if (ge == null) return;
    var opt = ge.getOptions();
    ge.getNavigationControl().setVisibility(f1?ge.VISIBILITY_SHOW:ge.VISIBILITY_HIDE);
    ge.getNavigationControl().setControlType(ge.NAVIGATION_CONTROL_SMALL);
    opt.setScaleLegendVisibility(f2);
    opt.setOverviewMapVisibility(f3);
    opt.setGridVisibility(f4);
    opt.setStatusBarVisibility(f5);
    ge.getLayerRoot().enableLayerById(ge.LAYER_TERRAIN,f6);
    ge.getLayerRoot().enableLayerById(ge.LAYER_ROADS,f7);
    ge.getLayerRoot().enableLayerById(ge.LAYER_BUILDINGS,f8);
    ge.getLayerRoot().enableLayerById(ge.LAYER_BUILDINGS_LOW_RESOLUTION,f8);
    ge.getLayerRoot().enableLayerById(ge.LAYER_BORDERS,f9);
    altmode = f10?ge.ALTITUDE_ABSOLUTE:ge.ALTITUDE_CLAMP_TO_GROUND;
}
```

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

### Generate LineString Track

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Debug_Build/rtkplot_ge.htm

Generates a placemark with a line string geometry for displaying tracks.

```javascript
function GenLine(name,color) {
    var pm = ge.createPlaceMark('');
    var ls = ge.createLineString('');
    var style = ge.createStyle('');
    style.getLineStyle().setWidth(3);
    style.getLineStyle().getColor().set(color);
    pm.setDescription(name);
    pm.setGeometry(ls);
    pm.setStyleSelector(style);
    ge.getFeatures().appendChild(pm);
    return pm;
}
```

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

### GPT Subroutine Definition

Source: https://github.com/tomojitakasu/rtklib/blob/master/lib/iers/src/gpt.f.org

Defines the GPT subroutine, its parameters, and associated variables. Includes constants and data initialization for geoid models.

```fortran
      SUBROUTINE GPT (DMJD,DLAT,DLON,DHGT,PRES,TEMP,UNDU)
*+ 
*  - - - - - - - - - 
*   G P T 
*  - - - - - - - - - 
*
*  This routine is part of the International Earth Rotation and
*  Reference Systems Service (IERS) Conventions software collection.
*
*  This subroutine determines Global Pressure and Temperature (Boehm et al. 2007)
*  based on Spherical Harmonics up to degree and order 9.
*
*  In general, Class 1, 2, and 3 models represent physical effects that
*  act on geodetic parameters while canonical models provide lower-level
*  representations or basic computations that are used by Class 1, 2, or
*  3 models.
* 
*  Status: Class 1 model	
*
*     Class 1 models are those recommended to be used a priori in the
*     reduction of raw space geodetic data in order to determine
*     geodetic parameter estimates.
*     Class 2 models are those that eliminate an observational
*     singularity and are purely conventional in nature.
*     Class 3 models are those that are not required as either Class
*     1 or 2.
*     Canonical models are accepted as is and cannot be classified as a
*     Class 1, 2, or 3 model.
*
*  Given:
*     DMJD           d      Modified Julian Date
*     DLAT           d      Latitude given in radians (North Latitude)
*     DLON           d      Longitude given in radians (East Longitude)
*     DHGT           d      Ellipsoidal height in meters
*
*  Returned:
*     PRES           d      Pressure given in hPa
*     TEMP           d      Temperature in degrees Celsius
*     UNDU           d      Geoid undulation in meters (Note 1)
*
*  Notes:
*
*  1) This is from a 9x9 Earth Gravitational Model (EGM).
*
*  Test case:
*     given input: DMJD = 55055D0
*                  DLAT = 0.6708665767D0 radians (NRAO, Green Bank, WV)
*                  DLON = -1.393397187D0 radians
*                  DHGT = 812.546 meters
*     expected output: PRES = 919.1930225603726967D0 hPa 
*                      TEMP = 28.94460920276309679D0 degrees Celsius
*                      UNDU = -42.78796423912972813D0 meters
*
*  References:
*
*     Boehm, J., Heinkelmann, R. and Schuh, H., 2007, "Short Note: A 
*     Global model of pressure and temperature for geodetic applications",
*     Journal of Geodesy, 81(10), pp. 679-683.
*
*     Petit, G. and Luzum, B. (eds.), IERS Conventions (2010),
*     IERS Technical Note No. 36, BKG (2010)
*
*  Revisions:
*  2006 June 12 J. Boehm    Original code
*  2006 June 16 J. Boehm    Accounted for geoid undulation
*  2006 August 14 O. Montenbruck Recursions for Legendre polynomials
*  2009 February 13 B.E. Stetzler Added header and copyright
*  2009 March 30 B.E. Stetzler More modifications and defined twopi
*  2009 March 31 B.E. Stetzler Provided test case
*  2009 July  29 B.E. Stetzler Capitalized all variables for FORTRAN 77
*                              compatibility and corrected test case
*                              latitude and longitude coordinates
*-----------------------------------------------------------------------

      IMPLICIT NONE

      DOUBLE PRECISION DMJD,DLAT,DLON,DHGT,PRES,TEMP,UNDU

      DOUBLE PRECISION V(10,10),W(10,10),
     . AP_MEAN(55),BP_MEAN(55),AP_AMP(55),BP_AMP(55),
     . AT_MEAN(55),BT_MEAN(55),AT_AMP(55),BT_AMP(55),
     . A_GEOID(55),B_GEOID(55)

      INTEGER*4 I,N,M,NMAX,MMAX
      DOUBLE PRECISION TWOPI,DOY,TEMP0,PRES0,
     . APM,APA,ATM,ATA,HORT,X,Y,Z

      PARAMETER (TWOPI = 6.283185307179586476925287D0)

      DATA (A_GEOID(I),I=1,55)/
     .-5.6195D-001,-6.0794D-002,-2.0125D-001,-6.4180D-002,-3.6997D-002,
     .+1.0098D+001,+1.6436D+001,+1.4065D+001,+1.9881D+000,+6.4414D-001,
     .-4.7482D+000,-3.2290D+000,+5.0652D-001,+3.8279D-001,-2.6646D-002,
     .+1.7224D+000,-2.7970D-001,+6.8177D-001,-9.6658D-002,-1.5113D-002,
     .+2.9206D-003,-3.4621D+000,-3.8198D-001,+3.2306D-002,+6.9915D-003,
     .-2.3068D-003,-1.3548D-003,+4.7324D-006,+2.3527D+000,+1.2985D+000,
     .+2.1232D-001,+2.2571D-002,-3.7855D-003,+2.9449D-005,-1.6265D-004,
     .+1.1711D-007,+1.6732D+000,+1.9858D-001,+2.3975D-002,-9.0013D-004,
     .-2.2475D-003,-3.3095D-005,-1.2040D-005,+2.2010D-006,-1.0083D-006,
     .+8.6297D-001,+5.8231D-001,+2.0545D-002,-7.8110D-003,-1.4085D-004,
     .-8.8459D-006,+5.7256D-006,-1.5068D-006,+4.0095D-007,-2.4185D-008/ 

      DATA (B_GEOID(I),I=1,55)/
     .+0.0000D+000,+0.0000D+000,-6.5993D-002,+0.0000D+000,+6.5364D-002,
     .-5.8320D+000,+0.0000D+000,+1.6961D+000,-1.3557D+000,+1.2694D+000,
     .+0.0000D+000,-2.9310D+000,+9.4805D-001,-7.6243D-002,+4.1076D-002,
     .+0.0000D+000,-5.1808D-001,-3.4583D-001,-4.3632D-002,+2.2101D-003,
     .-1.0663D-002,+0.0000D+000,+1.0927D-001,-2.9463D-001,+1.4371D-003,
     .-1.1452D-002,-2.8156D-003,-3.5330D-004,+0.0000D+000,+4.4049D-001,
     .+5.5653D-002,-2.0396D-002,-1.7312D-003,+3.5805D-005,+7.2682D-005,
     .+2.2535D-006,+0.0000D+000,+1.9502D-002,+2.7919D-002,-8.1812D-003,
     .+4.4540D-004,+8.8663D-005,+5.5596D-005,+2.4826D-006,+1.0279D-006/
```

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

### Added Library Source Files in RTKLIB 2.2.1

Source: https://github.com/tomojitakasu/rtklib/blob/master/doc/doc/relnotes_2.2.1.txt

New source files added in version 2.2.1. These files implement new functionalities or modules.

```c
convrnx.c, rcvraw.c, rtcm.c
```

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

### Generate Placemark Marker

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Debug_Build/rtkplot_ge.htm

Generates a placemark with a custom icon for use as a marker.

```javascript
function GenMark(name,mark_icon) {
    var pm = ge.createPlacemark('');
    var icon = ge.createIcon('');
    icon.setHref(mark_icon);
    var style = ge.createStyle('');
    style.getIconStyle().setIcon(icon);
    style.getIconstyle().getHotSpot().set(0.5,ge.UNITS_FRACTION,0,ge.UNITS_FRACTION);
    pm.setDescription(name);
    pm.setStyleSelector(style);
    ge.getFeatures().appendChild(pm);
    return pm;
}
```

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

### Compute Zenith Delay Coefficient (VMF1W)

Source: https://github.com/tomojitakasu/rtklib/blob/master/lib/iers/src/vmf1_ht.f.org

Calculates the zenith delay coefficient for the VMF1 model, often referred to as VMF1W. This is used in conjunction with other atmospheric parameters to determine total delays.

```Fortran
      BW = 0.00146D0
      CW = 0.04391D0
      BETA   = BW/( SINE + CW )
      GAMMA  = AW/( SINE + BETA)
      TOPCON = (1D0 + AW/(1D0 + BW/(1D0 + CW)))
      VMF1W  = TOPCON/(SINE+GAMMA)
```

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

### Set Map View

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Release_Build/rtkplot_gm.htm

Sets the center and zoom level of the map. Returns early if the map is not initialized.

```javascript
function SetView(lat,lon,zoom) {
    if (map == null) return;
    map.setCenter(new google.maps.LatLng(lat,lon));
    map.setZoom(zoom);
}
```

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

### Added APIs in RTKLIB 2.2.1

Source: https://github.com/tomojitakasu/rtklib/blob/master/doc/doc/relnotes_2.2.1.txt

List of new API functions added in version 2.2.1. These functions provide new capabilities for data processing and receiver interaction.

```c
satno(), satsys(), satid2no(), satno2id(), traceb(), geph2pos(), convrnx(),
getbitu(), getbits(), crc32(), crc24q(), decode_word(), decode_frame(),
init_raw(), free_raw(), input_raw(), input_rawf(), input_oem4(), input_oem3(),
input_ubx(), input_ss2(), input_cres(), input_oem4f(), input_oem3f(),
input_ubxf(), input_ss2f(), input_cresf(), init_rtcm(), free_rtcm(),
input_rtcm2(), input_rtcm3(), input_rctm2f(), input_rtcm3f(), outnmea_rmc(),
outnmea_gga(), outnmea_gsa(), outnmea_gsv()
```

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

### Show Marker

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Release_Build/rtkplot_gm.htm

Makes a marker visible on the map, identified by its title. Searches through the 'marks' array.

```javascript
function ShowMark(title) {
    for (var i in marks) {
        if (marks[i].title==title) {
            marks[i].setVisible(true);
            break;
        }
    }
}
```

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

### Set Camera Tilt

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Debug_Build/rtkplot_ge.htm

Sets the camera's tilt (angle from the horizon) in degrees.

```javascript
function SetTilt(angle) {
    if (ge == null) return;
    var la = ge.getView().copyAsLookAt(ge.ALTITUDE_RELATIVE_TO_GROUND);
    la.setTilt(angle);
    ge.getView().setAbstractView(la);
}
```

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

### Modified APIs in RTKLIB 2.2.1

Source: https://github.com/tomojitakasu/rtklib/blob/master/doc/doc/relnotes_2.2.1.txt

List of API functions that have been modified in version 2.2.1. Check the documentation for specific changes in behavior or parameters.

```c
outrnxobsh(), outrnxobsb(), outrnxnavh(), outrnxnavb(), outsols(), outsol(),
sbsreadmsg(), sbsreadmsgt(), sbsdecodemsg(), sbspntpos(), strsvrstart(),
rtksvrstart()
```

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

### Set Camera Heading

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Debug_Build/rtkplot_ge.htm

Sets the camera's heading (direction it's facing) in degrees.

```javascript
function SetHeading(angle) {
    if (ge == null) return;
    var la = ge.getView().copyAsLookAt(ge.ALTITUDE_RELATIVE_TO_GROUND);
    la.setHeading(angle);
    ge.getView().setAbstractView(la);
}
```

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

### Set Camera View

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Debug_Build/rtkplot_ge.htm

Sets the camera's position and orientation in Google Earth.

```javascript
function SetView(lat,lon,range,heading) {
    if (ge == null) return;
    var la = ge.getView().copyAsLookAt(ge.ALTITUDE_RELATIVE_TO_GROUND);
    la.setLatitude (lat);
    la.setLongitude(lon);
    la.setRange(range*1000.0);
    la.setHeading(heading);
    ge.getView().setAbstractView(la);
}
```

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

### Show/Hide Placemark Marker

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Debug_Build/rtkplot_ge.htm

Controls the visibility of a specific placemark marker.

```javascript
function ShowMark(index) {
    if (ge == null) return;
    var mark = index==1?mark1:mark2;
    mark.setVisibility(1);
}

function HideMark(index) {
    if (ge == null) return;
    var mark = index==1?mark1:mark2;
    mark.setVisibility(0);
}
```

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

### VMF1 Mapping Function Calculation (Fortran)

Source: https://github.com/tomojitakasu/rtklib/blob/master/lib/iers/src/vmf1.f.org

Calculates the hydrostatic (VMF1H) and wet (VMF1W) mapping functions using site-specific coefficients and atmospheric conditions. Ensure input latitude is in radians.

```Fortran
SUBROUTINE VMF1 (AH,AW,DMJD,DLAT,ZD,VMF1H,VMF1W)
*+ 
*  - - - - - - - - - 
*   V M F 1 
*  - - - - - - - - - 
*
*  This routine is part of the International Earth Rotation and
*  Reference Systems Service (IERS) Conventions software collection.
*
*  This subroutine determines the Vienna Mapping Function 1 (VMF1) (Boehm et al, 2006).
*  This is the site dependent version. 
*
*  In general, Class 1, 2, and 3 models represent physical effects that
*  act on geodetic parameters while canonical models provide lower-level
*  representations or basic computations that are used by Class 1, 2, or
*  3 models. 
*
*  Status: Class 1 model	
*
*     Class 1 models are those recommended to be used a priori in the
*     reduction of raw space geodetic data in order to determine
*     geodetic parameter estimates.
*     Class 2 models are those that eliminate an observational
*     singularity and are purely conventional in nature.
*     Class 3 models are those that are not required as either Class
*     1 or 2. 
*     Canonical models are accepted as is and cannot be classified as a
*     Class 1, 2, or 3 model.
*
*  Given:
*     AH             d      Hydrostatic coefficient a (Note 1) 
*     AW             d      Wet coefficient a (Note 1) 
*     DMJD           d      Modified Julian Date
*     DLAT           d      Latitude given in radians (North Latitude)
*     ZD             d      Zenith distance in radians
*
*  Returned:
*     VMF1H           d      Hydrostatic mapping function (Note 2)
*     VMF1W           d      Wet mapping function (Note 2)
*
*  Notes:
*
*  1) The coefficients can be obtained from the primary website
*     http://ggosatm.hg.tuwien.ac.at/DELAY/ or the back-up website
*     http://www.hg.tuwien.ac.at/~ecmwf1/. 
*
*  2) The mapping functions are dimensionless scale factors.
*
*  Test case:
*     given input: AH   = 0.00125711D0 
*                  AW   = 0.00058801D0
*                  DMJD = 55055D0
*                  DLAT = 0.6708665767D0 radians (NRAO, Green Bank, WV)
*                  ZD   = 1.278564131D0 radians
*
*     expected output: VMF1H = 3.425054275537719128D0
*                      VMF1W = 3.449100942061193553D0
*                     
*  References:
*
*     Boehm, J., Werl, B., and Schuh, H., (2006), 
*     "Troposhere mapping functions for GPS and very long baseline
*     interferometry from European Centre for Medium-Range Weather
*     Forecasts operational analysis data," J. Geophy. Res., Vol. 111,
*     B02406, doi:10.1029/2005JB003629
*
*     Petit, G. and Luzum, B. (eds.), IERS Conventions (2010),
*     IERS Technical Note No. 36, BKG (2010)
*
*  Revisions:
*  2005 October 02 J. Boehm          Original code
*  2009 August 17 B.E. Stetzler      Added header and copyright
*  2009 August 17 B.E. Stetzler      More modifications and defined twopi
*  2009 August 17 B.E. Stetzler      Provided test case
*  2009 August 17 B.E. Stetzler      Capitalized all variables for FORTRAN 77
*                                    compatibility 
*  2010 September 08 B.E. Stetzler   Provided new primary website to obtain
*                                    VMF coefficients
*----------------------------------------------------------------------

      IMPLICIT NONE
     
      DOUBLE PRECISION AH, AW, DMJD, DLAT, ZD, VMF1H, VMF1W 

      DOUBLE PRECISION DOY, BH, C0H, C11H, C10H, PHH, CH, SINE, BETA,
     .                 GAMMA, TOPCON, BW, CW, PI, TWOPI

      PARAMETER ( PI = 3.1415926535897932384626433D0 )
      PARAMETER (TWOPI = 6.283185307179586476925287D0)

*+--------------------------------------------------------------------*
*     Reference day is 28 January 1980
*     This is taken from Niell (1996) to be consistent
*----------------------------------------------------------------------
      DOY = DMJD  - 44239D0 + 1 - 28
      
      BH = 0.0029D0;
      C0H = 0.062D0
      IF (DLAT.LT.0D0) THEN   ! southern hemisphere
          PHH  = PI
          C11H = 0.007D0
          C10H = 0.002D0
      ELSE                    ! northern hemisphere
          PHH  = 0D0
          C11H = 0.005D0
          C10H = 0.001D0
      END IF
      CH = C0H + ((DCOS(DOY/365.25D0*TWOPI + PHH)+1D0)*C11H/2D0 
     .     + C10H)*(1D0-DCOS(DLAT))


      SINE   = DSIN(PI/2D0 - ZD)
      BETA   = BH/( SINE + CH  )
      GAMMA  = AH/( SINE + BETA)
      TOPCON = (1D0 + AH/(1D0 + BH/(1D0 + CH)))
      VMF1H   = TOPCON/(SINE+GAMMA)

      BW = 0.00146D0
      CW = 0.04391D0
      BETA   = BW/( SINE + CW )
      GAMMA  = AW/( SINE + BETA)
      TOPCON = (1D0 + AW/(1D0 + BW/(1D0 + CW)))
      VMF1W   = TOPCON/(SINE+GAMMA)
      
* Finished.

*+----------------------------------------------------------------------
*
*  Copyright (C) 2008
*  IERS Conventions Center
*
*  ==================================
*  IERS Conventions Software License
*  ==================================
*
*  NOTICE TO USER:
*
*  BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING TERMS AND CONDITIONS
*  WHICH APPLY TO ITS USE.
*

```

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

### Deleted APIs in RTKLIB 2.2.1

Source: https://github.com/tomojitakasu/rtklib/blob/master/doc/doc/relnotes_2.2.1.txt

List of API functions removed in version 2.2.1. These functions are no longer available for use.

```c
readrnxf(), decodefrm(), decodenav(), addobs(), addnav(), addsbs(),
addionutc(), convlog(), readlog(), readlogs(), decodelog(), rtksvrgetsol(),
SAT(), PRN(), decodenov(), convnov(), readnov(), decodeubx(), convubx(),
readubx(), decodess2(), convss2(), readss2(), decodecres(), convcres(),
readcres()
```

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

### Set Placemark Position

Source: https://github.com/tomojitakasu/rtklib/blob/master/app/rtkplot/Debug_Build/rtkplot_ge.htm

Sets the latitude, longitude, and altitude for a specific placemark marker.

```javascript
function SetMark(index,lat,lon,alt) {
    if (ge == null) return;
    var mark = index==1?mark1:mark2;
    var point = ge.createPoint('');
    point.set(lat,lon,alt,altmode,1,1);
    mark.setGeometry(point);
}
```