Création de LineOfVisibility authored by Julien LEBLOND's avatar Julien LEBLOND
This page describes the content of a CZML document. Please read [How to get started]() for an explanation of how a CZML document is put together.
# LineOfVisibility
**Extends** : [CZMLPrimaryObjects](CZMLPrimaryObjects)
**Example** :
```json
{
"id":"Toulouse Frame/Keplerian parameters: {a: 6928000.0; e: 0.0; i: 60.00000000000001; pa: 0.0; raan: 90.0; v: 90.0;}",
"name":"Line between Toulouse Frame and Keplerian parameters: {a: 6928000.0; e: 0.0; i: 60.00000000000001; pa: 0.0; raan: 90.0; v: 90.0;}",
"availability":"0001-01-01T00:00:00Z/2022-01-17T13:00:00Z",
"polyline":{
"width":1,
"material":{
"solidColor":{
"color":{
"rgba":[
0,255,255,255
]
}
}
},
"arcType":"NONE",
"positions":{
"references":[
"VIS/Toulouse Frame/Keplerian parameters: {a: 6928000.0; e: 0.0; i: 60.00000000000001; pa: 0.0; raan: 90.0; v: 90.0;}#position",
"Keplerian parameters: {a: 6928000.0; e: 0.0; i: 60.00000000000001; pa: 0.0; raan: 90.0; v: 90.0;}#position"
]
},
"show":[
{
"interval":"0001-01-01T00:00:00Z/2022-01-17T13:00:00Z",
"boolean":false
}
]
}
},
```
# Properties
**id** - String : Identification of the line of visibility, *default* : " [Name of the ground station]/[Id of the satellite]".
**name** String : Name of the CZML ground station, *default* : "Line between [Name of the ground station] and [Name of the satellite].
**polyline** - [Polyline](Polyline) : A polyline object that represents the line that will be displayed to follow the satellite
## Intrinsic arguments
**TopocentricFrame** - [TopocentricFrame](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/frames/TopocentricFrame.html) : The Orekit Topocentric Frame
**angleOfAperture** - Double : The angle of aperture for the visiblity, *default* : 80.0°.
# Build
These arguments can be used to build a line of visibility object :
* A [Visibility Cone](VisibilityCone) :
```Java
LineOfVisibility lineOfVisibility = new LineOfVisibility(visibilityCone);
```
* A [Visibility Cone](VisibilityCone), an angle of aperture :
```Java
LineOfVisibility lineOfVisibility = new LineOfVisibility(visibilityCone, angleOfAperture);
```
* A [TopocentricFrame](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/frames/TopocentricFrame.html), a [Satellite](Satellite), a [Header](Header) :
```Java
LineOfVisibility lineOfVisibility = new LineOfVisibility(topocentricFrame, satellite, header);
```
* A [TopocentricFrame](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/frames/TopocentricFrame.html), a [Satellite](Satellite), a [Header](Header) , an angle of aperture :
```Java
LineOfVisibility lineOfVisibility = new LineOfVisibility(topocentricFrame, satellite, header, angleOfAperture);
```
* A [TopocentricFrame](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/frames/TopocentricFrame.html), a [Constellation](Constellation), a [Header](Header) : (**This builder will create all lines of visibility for all satellites of a constellation for a given ground station**)
```Java
LineOfVisibility lineOfVisibility = new LineOfVisibility(topocentricFrame, constellation, header);
```
* A [TopocentricFrame](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/frames/TopocentricFrame.html), a [Constellation](Constellation), a [Header](Header), an angle of aperture : (**This builder will create all lines of visibility for all satellites of a constellation for a given ground station**)
```Java
LineOfVisibility lineOfVisibility = new LineOfVisibility(topocentricFrame, constellation, header, angleOfAperture);
```
* A List<[TopocentricFrame](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/frames/TopocentricFrame.html)>, a [Constellation](Constellation), a [Header](Header) : (**This builder will create all lines of visibility for all satellites of a constellation for all the stations for each topocentricFrame**).
```Java
LineOfVisibility lineOfVisibility = new LineOfVisibility(topocentricFrameList, constellation, header);
```
* A List<[TopocentricFrame](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/frames/TopocentricFrame.html)>, a [Constellation](Constellation), a [Header](Header), an angle of aperture : (**This builder will create all lines of visibility for all satellites of a constellation for all the stations for each topocentricFrame**).
```Java
LineOfVisibility lineOfVisibility = new LineOfVisibility(topocentricFrameList, constellation, header, angleOfAperture);
```