Orbits

java.lang.Object
- org.das2.datum.Orbits

```
public class Orbits
extends java.lang.Object
```
Orbits are a map of string identifiers to DatumRanges, typically used to enumerate the orbits a spacecraft makes. For example, Cassini orbit "C" was from 2004-366T07:03 to 2005-032T03:27 and "33" was from 2006-318T23:34 to 2006-330T22:23. There are two types of orbits: canonical, which have an identifier like "cassini" and can be used by the community, and user which have identifiers like https://raw.githubusercontent.com/autoplot/orbits/main/psp/psp-aa25.txt. In either case, these refer to a file. The canonical ones are stored on the das2 website at http://das2.org/Orbits/<id>.dat. This file is a three-column ASCII file with the orbit id in either the first or last column. Note any line not meeting this spec is ignored, so that orbit files can contain additional documentation (and can sit within a wiki).

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class Orbits.OrbitFieldHandler
allow orbits to be used in file names

Nested Classes
Modifier and Type	Class and Description
`static class`	`Orbits.OrbitFieldHandler` allow orbits to be used in file names

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`compare(java.lang.String a, java.lang.String b)` return -1 if a is before b, 0 if they are equal, and 1 if a is after b.
`java.lang.String`	`first()` return the first orbit id, so that we can iterate through all
`DatumRange`	`getDatumRange(java.lang.String orbit)` return the DatumRange for this orbit number.
`java.lang.String`	`getOrbit(Datum d)` returns the first orbit containing the time, or null if none do.
`java.lang.String`	`getOrbitOnOrBefore(Datum d)` return the closest orbit on or before datum d.
`static Orbits`	`getOrbitsFor(java.lang.String sc)` Return the orbits for the named spacecraft, or those described in the file pointed to the URL when the "sc" identifier is a URL.
`java.lang.String`	`getSpacecraft()`
`static java.util.Map<java.lang.String,java.lang.String>`	`getSpacecraftIdExamples()` return examples of spacecraft ids which can be used, and a human-readable label in a linked hash map.
`java.net.URL`	`getURL()` return the URL used to populate the orbits.
`static boolean`	`isOrbitsFile(java.lang.String sc)` provide method for clients to see if the URI represents an orbits file, without constantly going into the synchronized block, which was causing things to hang for Masafumi.
`java.lang.String`	`last()`
`static void`	`main(java.lang.String[] args)`
`java.lang.String`	`next(java.lang.String orbit)` return the next orbit number, or null if there are no more orbit numbers.
`java.lang.String`	`prev(java.lang.String orbit)` return the previous orbit number, or null if there are no more orbit numbers.
`static void`	`reset()` reset the loaded missions.
`static Orbits`	`resetOrbitsFor(java.lang.String sc)` force a reload of the orbits file.
`static java.lang.String`	`trimOrbit(java.lang.String orbit)` Orbit numbers are typically just a number, but some missions like Cassini had letter names for orbits as well.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - getDatumRange
```
public DatumRange getDatumRange(java.lang.String orbit)
                         throws java.text.ParseException
```
    return the DatumRange for this orbit number. Note this IS NOT an OrbitDatumRange.
    
    Parameters:
    
    orbit -
    
    Returns:
    
    Throws:
    
    java.text.ParseException
  - getOrbit
```
public java.lang.String getOrbit(Datum d)
```
    returns the first orbit containing the time, or null if none do.
    
    Parameters:
    
    d -
    
    Returns:
    
    the orbit number or null
  - getOrbitOnOrBefore
```
public java.lang.String getOrbitOnOrBefore(Datum d)
```
    return the closest orbit on or before datum d.
    
    Parameters:
    
    d - the datum
    
    Returns:
    
    the id of the closest orbit before, or null.
    
    See Also:
    
    http://jfaden.net/~jbf/autoplot/script/demos/jeremy/onOrBefore.jy
  - next
```
public java.lang.String next(java.lang.String orbit)
```
    return the next orbit number, or null if there are no more orbit numbers.
    
    Parameters:
    
    orbit -
    
    Returns:
    
    the orbit number or null.
  - prev
```
public java.lang.String prev(java.lang.String orbit)
```
    return the previous orbit number, or null if there are no more orbit numbers.
    
    Parameters:
    
    orbit -
    
    Returns:
    
    the orbit number or null.
  - trimOrbit
```
public static java.lang.String trimOrbit(java.lang.String orbit)
```
    Orbit numbers are typically just a number, but some missions like Cassini had letter names for orbits as well. This encapsulates the code to identify the canonical orbit from the string, by removing trailing _'s and 0's.
    
    Parameters:
    
    orbit -
    
    Returns:
  - compare
```
public int compare(java.lang.String a,
                   java.lang.String b)
```
    return -1 if a is before b, 0 if they are equal, and 1 if a is after b.
    
    Parameters:
    
    a -
    
    b -
    
    Returns:
  - first
```
public java.lang.String first()
```
    return the first orbit id, so that we can iterate through all
    
    Returns:
  - last
```
public java.lang.String last()
```
  - getSpacecraft
```
public java.lang.String getSpacecraft()
```
  - getSpacecraftIdExamples
```
public static java.util.Map<java.lang.String,java.lang.String> getSpacecraftIdExamples()
```
    return examples of spacecraft ids which can be used, and a human-readable label in a linked hash map. This may fall out-of-sync with the list of IDs which would work (see https://das2.org/Orbits/), but this should be considered a bug.
    
    Returns:
    
    map from id to description.
  - reset
```
public static void reset()
```
    reset the loaded missions.
  - resetOrbitsFor
```
public static Orbits resetOrbitsFor(java.lang.String sc)
```
    force a reload of the orbits file. TODO: ideally the freshness of the orbits file would be checked every ten seconds, but there's quite a bit of coding to do that properly. This will force the reload, for example when the green play button is pressed on the Autoplot Events List.
    
    Parameters:
    
    sc - the string identifier for the spacecraft, such as "rbspa-pp", or URL to orbit file.
    
    Returns:
    
    reread Orbits.
  - getOrbitsFor
```
public static Orbits getOrbitsFor(java.lang.String sc)
```
    Return the orbits for the named spacecraft, or those described in the file pointed to the URL when the "sc" identifier is a URL. Example files may be on the wiki page http://das2.org/wiki/index.php/Orbits.<SC%gt;, or on the classpath in /orbits/<SC>.dat The orbits file will be read by ignoring any line that does not contain three non-space blobs, and either the first two or last two should parse as an ISO8601 string. The ISO8601 strings must start with 4-digit years, either Note the input can then be html, with a pre section containing the orbits. Note the wiki page is the source for cassini and crres, but other missions may come from special places encoded here. Mediawiki introduced two problems: first, that typos were not identified clearly because a 200 (ok) code is returned for any URL. Second, it's not trivial to set up mirrors that put data into the wiki. For this reason, the wiki should only be used as a reference for humans and other use is discouraged. This now uses special code for rbspb-pp and rbspa-pp that looks at UIowa, LANL and at virbo.org. This should not be called from the event thread, because it may block briefly while the orbits are loaded.
    
    Parameters:
    
    sc - the string identifier for the spacecraft, such as "rbspa-pp", or URL to orbit file.
    
    Returns:
    
    the Orbits file which can be used to query orbits.
    
    Throws:
    
    java.lang.IllegalArgumentException - when the orbits file cannot be read
  - isOrbitsFile
```
public static boolean isOrbitsFile(java.lang.String sc)
```
    provide method for clients to see if the URI represents an orbits file, without constantly going into the synchronized block, which was causing things to hang for Masafumi.
    
    Parameters:
    
    sc - the string identifier for the spacecraft, such as "rbspa-pp", or URL to orbit file.
    
    Returns:
    
    true if the uri refers to orbits.
  - getURL
```
public java.net.URL getURL()
```
    return the URL used to populate the orbits.
    
    Returns:
  - main
```
public static void main(java.lang.String[] args)
                 throws java.text.ParseException
```
    Throws:
    
    java.text.ParseException

Class Orbits

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Method Detail

getDatumRange

getOrbit

getOrbitOnOrBefore

next

prev

trimOrbit

compare

first

last

getSpacecraft

getSpacecraftIdExamples

reset

resetOrbitsFor

getOrbitsFor

isOrbitsFile

getURL

main