﻿IsoElevationCircle Method (, , Double, Double, Double, Double)
Calculates an elevation circle centered on an earth site.

Namespace: Zeptomoby.OrbitTools.Track
Assembly: Zeptomoby.OrbitTools.Track (in Zeptomoby.OrbitTools.Track.dll) Version: 1.5.0.0 (1.5.0.0)

# Syntax

C#
```public static List<Geo> IsoElevationCircle(
this Site site,
Julian date,
double kmTargetAlt,
double degAngle,
double kmSpacing,
double kmLoft
)```
Visual Basic
```<ExtensionAttribute> _
Public Shared Function IsoElevationCircle ( _
site As Site, _
date As Julian, _
kmTargetAlt As Double, _
degAngle As Double, _
kmSpacing As Double, _
kmLoft As Double _
) As List(Of Geo)```
Visual C++
```[ExtensionAttribute]
public:
static List<Geo^>^ IsoElevationCircle(
Site^ site,
Julian^ date,
double kmTargetAlt,
double degAngle,
double kmSpacing,
double kmLoft
)```

#### Parameters

site
Type: Site
The earth site.
date
Type: Julian
Time of calculation.
kmTargetAlt
Type: System..::..Double
Target location, in kilometers directly above the earth site.
degAngle
Type: System..::..Double
The viewing angle, from the earth site to an arbitrary target height, [0..90] degrees.
kmSpacing
Type: System..::..Double
The distance between each point in the circle, in kilometers.
kmLoft
Type: System..::..Double
The height of the circle above the earth ellipsoid model, in kilometers.

#### Return Value

A list of geodetic coordinate points that form a circle on the surface of the earth, centered around a given site location. The points all have the same viewing angle of elevation to a target point located at an arbitrary distance above the site.

#### Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type Site. When you use instance method syntax to call this method, omit the first parameter. For more information, see or .

# Remarks

The returned points do not always form a perfect circle due to the Earth's equatorial bulge.