mise à jour du 15 février 2018 : voir ce article de livre de cuisine pour un moyen plus simple
mise à jour du 10 avril 2018 : voir Bryan's scénario pour une approche moderne
Mémoire précoce
Quand j'avais presque trois ans, mon père, W4FNB, SK, m'a laissé traîner dans la salle de radio pendant qu'il écoutait le signal de Spoutnik .Je me souviens qu'il expliquait comment le décalage Doppler l'obligeait à ajuster continuellement le réglage du signal. Hammarlund destinataire QG-129X , et comment il était important que le récepteur chauffe pendant plusieurs heures pour stabiliser les oscillateurs internes de la radio.Je pense qu'il a essayé de me montrer quelque chose dans le ciel aussi, mais il a fallu encore quatre ans avant que l'infirmière de l'école ne réalise à quel point j'avais besoin de lunettes.Sons des premiers satellites
Plus récemment
Le Station spatiale internationale est en orbite depuis 1998, ou 2000. Ce post a présenté JSL pour récupérer l'emplacement actuel de l'ISS et le tracer sur une carte construite à partir d'une autre image de la NASA.J'ai légèrement modifié le JSL et réalisé une vidéo montrant quelques jours d'orbites de 90 minutes en moins d'une minute.
Quelques améliorations mais assez similaires.J'ai gâché les noms de fichiers en ne remplissant pas les zéros non significatifs Mixeur attend; J'ai utilisé JSL pour renommer les fichiers.
// code repaired 15feb2018, requires JMP 11 or later
// trimmed down JSON parser (go get the real one, there is more support for tables)
/*
* JSL JSON Parser, Xan Gregg, 2014-12-29
* pattern matching speedup, Craige Hales, 2015-01-01
*/
New Namespace( "JSON" );
JSON:Char Escape = Function( {c},
Match( c, "\!"", "\!"", "b", "\!u0008", "f", "\!u000C", "n", "\!u000A", "r", "\!u000D", "t", "\!u0009", c )
);
JSON:Unicode Escape = Function( {u},
u = "\!"\!\!u" || u || "\!"";
Parse( u );
);
JSON:Pattern Name = "\!"" // leading quotation mark
+ Pat Test(
value = "";
1;
) // init string accumulator
+ Pat Repeat(
(Pat Break( "\!\\!"" ) >> temp + Pat Test(
value ||= temp;
1;
)) // run of characters that are not \ or "
| ("\u" + Pat Len( 4 ) >> temp + Pat Test(
value ||= JSON:Unicode Escape( temp );
1;
)) // \uXXXX
| ("\" + Pat Len( 1 ) >> temp + Pat Test(
value ||= JSON:Char Escape( temp );
1;
)) // \", for example...embedded quotation mark
) + "\!""; // trailing quotation mark
JSON:Pattern Number = Pat Span( "0123456789-+eE." ) >> temp + Pat Test(
value = Num( temp );
1;
);
JSON:PatternParse = Pat Pos( 0 ) + Pat Repeat(
Pat Pos( /* remember how far we parsed for error message */ ) >> failpos// /* comment out this line for a little more speed */+pattest(if(tickseconds()-lasttime>1,lasttime=tickseconds();wait(0));1)
+ Pat Fence( /* fence off previously parsed text...ain't no going back */ ) + (Pat Regex( "\s*" ) // ignore whitespace
| JSON:Pattern Name | (":" + Pat Test(
key = value;
1;
)) | JSON:Pattern Number | ("true" + Pat Test(
value = 1;
1;
)) | ("false" + Pat Test(
value = 0;
1;
)) | ("null" + Pat Test(
value = .;
1;
)) | ("[" + Pat Test(
Insert Into( stack, {{}}, 1 );
value = Empty();
1;
)) | ("{" + Pat Test(
Insert Into( stack, Associative Array(), 1 );
value = Empty();
Insert Into( keys, key, 1 );
1;
)) | ("]" + Pat Test(
If( !Is Empty( value ),
Insert Into( stack[1], value, 1 /*needs reverse later*/ )
);
value = stack[1];
value = Reverse( value );
Remove From( stack, 1 );
1;
)) | ("}" + Pat Test(
If( !Is Empty( value ),
stack[1][key] = value
);
value = stack[1];
Remove From( stack, 1 );
key = keys[1];
Remove From( keys, 1 );
1;
)) | ("," + Pat Test(
If( Is List( stack[1] ),
Insert Into( stack[1], value, 1 /*needs reverse later*/ ),
stack[1][key] = value
);
value = Empty();
1;
)))
) + Pat R Pos( 0 );
JSON:jsonParse = Function( {json},
{stack = {}, keys = {}, key = "", value = Empty(), temp = 0, totalLen = Length( json ), failpos = 0},
If( !Try( Pat Match( json, JSON:PatternParse ), 0 ),
Throw( "unrecognized JSON at " || Char( failpos ) )
);
value;
);
// end namespace
lat = J( 3600, 1, . ); // trail of previous points, you can make it longer
lon = J( N Rows( lat ), 1, . );
idx = 1;
cur = idx;
error = "";
time = "";
dir = "D:\directory\ISS\m";
seq = 0;
/* open-notify.org (Thanks!) returns JSON data like this:
{
"iss_position": {
"latitude": 24.94415308475734,
"longitude": 116.70173230986174
},
"message": "success",
"timestamp": 1462990726
}
*/
updateLatLon = Function( {},
{where = Try(
loadtextfile( "http://api.open-notify.org/iss-now.json?" || Char( Random Integer( 1, 1e6 ) ) )
//Open( "http://api.open-notify.org/iss-now.json?" || Char( Random Integer( 1, 1e6 ) ) )
, "" ), // fetch a JSON string
locationData = JSON:jsonParse( where ) // use XAN's parser
},
If( !Is Empty( locationData ) & locationData["message"] == "success",
error = ""; // clear any previous message
lat[idx] = Num( locationData["iss_position"]["latitude"] ); // get the two numbers
lon[idx] = Num( locationData["iss_position"]["longitude"] ); // used in the script below to plot a point
time = locationData["timestamp"]; // unix time, not JMP time
time = Format( 1jan1970 + time, /*"ddMonyyyyh:m:s"*/ "yyyy-mm-ddThh:mm:ss" ) || " GMT";
cur = idx;
idx++;
If( idx > N Rows( lat ),
idx = 1
);
,
error = "no location data available"
);
Try(
g << inval;
Wait( 1 );
seq++;
g[framebox( 1 )] << savepicture( dir || Char( seq ) || ".png", "png" );
); // if the map exists, update it.
Schedule( 28, updateLatLon() ); // schedule this function to run again. it would be rude to ask for updates much faster than this.
);
updateLatLon(); // bootstrap call, then it calls itself every 30 seconds
earthLight = Open( "http://eoimages.gsfc.nasa.gov/images/imagerecords/55000/55167/earth_lights_lrg.jpg", "jpg" );
{width, height} = earthLight << size; // need the ratio for the frame size...
New Window( "NASA's Night Light Map",
g = Graph Box(
framesize( width / 2, height / 2 ),
X Scale( -180, 180 ),
Y Scale( -90, 90 ),
Text Color( "white" );
Text( {0, -50}, error );
Text( {-150, -88}, time );
Text( {-179, 80}, "International Space Station" );
Text( RightJustified, {160, -88}, "http://visibleearth.nasa.gov" ); // credits
Text( {-50, -88}, "http://open-notify.org/Open-Notify-API/ISS-Location-Now/" ); // credits
//Marker Size( 2 ); Marker( Combine States( Color State( "RED" ), Marker State( 12 ) ), lon, lat ); // space station trail
//Marker Size( 4 ); Marker( Combine States( Color State( "RED" ), Marker State( 12 ) ), {lon[cur], lat[cur]} ); // head
bright = N Rows( lon );
Marker Size( 4 );
For( i = cur, i >= 1, i--,
Marker( Combine States( Color State( RGB Color( bright / N Rows( lon ), 0.1, 0.1 ) ), Marker State( 12 ) ), {lon[i], lat[i]} );
bright--;
Marker Size( 2 );
);
For( i = N Rows( lon ), i > cur, i--,
Marker( Combine States( Color State( RGB Color( bright / N Rows( lon ), 0.1, 0.1 ) ), Marker State( 12 ) ), {lon[i], lat[i]} );
bright--;
);
)
);
frameBox = g[framebox( 1 )]; // the framebox, in the graphbox, is just inside the axes
frameBox << Background Map( Boundaries( "World" ) ); // add boundaries first; they wind up on top of the next bitmap...
g[axisbox( 1 )] << Scale( "Linear" ) << remove axis label; // the geo coordinates were set when the map was added, but
g[axisbox( 2 )] << Scale( "Linear" ) << remove axis label; // we need linear coords to line up the map...
frameBox << AddImage( Image( earthLight ), bounds( Left( -180 ), Right( 180 ), top( 90 ), bottom( -90 ) ) ); // -180..180 seems correct
imgSeg = frameBox << FindSeg( PictSeg( 1 ) ); // the most recently added one is first
imgSeg << lock( 1 ); // and lock it so mouse won't move it by mistake
frameBox << xaxis( show major ticks( false ), show minor ticks( false ), show labels( false ) );
frameBox << yaxis( show major ticks( false ), show minor ticks( false ), show labels( false ) );
