height

Height of point on surface

Since R2022a

Syntax

hgt = height(surface,pt)

hgt = height(surface,pt,t)

Description

hgt = height(surface,pt) returns the height hgt of the point pt on the surface. This syntax applies when the surface is a LandSurface, SeaSurface, or CustomSurface object.

hgt = height(surface,pt,t) returns the height hgt of the point pt on the surface at the time t. This syntax only applies when the surface is a SeaSurface object.

Examples

Find Height of Sea Surface

Create a square sea surface area using the seaSurface object. Assume a moderate sea state with a wind speed of about 10 m/s, a fetch of 250 km and a length of 1.0 km. Add an Elfouhaily spectrum to the sea surface. Use the height function to determine the heights of 2 points on the map.

Create a radar scenario.

scene = radarScenario(IsEarthCentered = false);
rng('default')

Add a sea surface to the scene with an Elfouhaily spectrum.

spec = seaSpectrum(Resolution = 20);
srf = seaSurface(scene,Boundary = [-500 500; -500 500], ...
    WindSpeed = 10,Fetch = 250000,SpectralModel = spec);

Find the height at two points.

P1 = [0;0];
P2 = [30;-70];
H = height(srf,[P1 P2])

H = 1×2

   -0.9394   -0.2682

Display the sea surface properties in the surface manager.

mgr = scene.SurfaceManager

mgr = 
  SurfaceManager with properties:

    EnableMultipath: 0
       UseOcclusion: 1
           Surfaces: [1×1 radar.scenario.SeaSurface]

mgr.Surfaces

ans = 
  SeaSurface with properties:

                WindSpeed: 10
            WindDirection: 0
                    Fetch: 250000
            SpectralModel: [1×1 seaSpectrum]
        RadarReflectivity: [1×1 surfaceReflectivitySea]
    ReflectionCoefficient: [1×1 radar.scenario.SurfaceReflectionCoefficient]
          ReflectivityMap: 1
          ReferenceHeight: 0
                 Boundary: [2×2 double]

Find Height of Land Surface

Create a radar scenario. Add a 400-by-400 m area to the scenario with two simulated hills. Find the height of two points.

scene = radarScenario('IsEarthCentered',false);
bnds = [-200 200; -200, 200];
x = -200:200;
y = -200:200;
[X,Y] = meshgrid(x,y);
htmap = 20*exp(-X.^2/2000 - Y.^2/2000) + 10*exp(-(X-70).^2/2000 - (Y+100).^2/2000);
surf(X,Y,htmap)
shading interp

Find the height of the surface at two points.

P1 = [0.0; 0.0]; % Point 1
P2 = [28.0; -40.0];  % Point 2
srf = landSurface(scene,'Terrain',htmap,'Boundary',bnds)

srf = 
  LandSurface with properties:

        RadarReflectivity: [1×1 surfaceReflectivityLand]
    ReflectionCoefficient: [1×1 radar.scenario.SurfaceReflectionCoefficient]
          ReflectivityMap: 1
          ReferenceHeight: 0
                 Boundary: [2×2 double]
                  Terrain: [401×401 double]

H = height(srf,[P1 P2])

H = 1×2

   20.0058    6.7565

Use the surface manager find the surfaces in the scenario.

mgr = scene.SurfaceManager

mgr = 
  SurfaceManager with properties:

    EnableMultipath: 0
       UseOcclusion: 1
           Surfaces: [1×1 radar.scenario.LandSurface]

mgr.Surfaces

ans = 
  LandSurface with properties:

        RadarReflectivity: [1×1 surfaceReflectivityLand]
    ReflectionCoefficient: [1×1 radar.scenario.SurfaceReflectionCoefficient]
          ReflectivityMap: 1
          ReferenceHeight: 0
                 Boundary: [2×2 double]
                  Terrain: [401×401 double]

Input Arguments

surface — Land, sea, or custom surface

LandSurface object | SeaSurface object | CustomSurface object

Surface, specified as a LandSurface, SeaSurface, or CustomSurface object.

pt — Point on surface

2-by-N matrix of real values | 3-by-N matrix of real values

Points on surface, specified as 2-by-N matrix of real values or a 3-by-N matrix of real values, where N is the number of points.

The coordinate system of the point depends on the value of the IsEarthCentered property of the radar scenario object::

• false — Each column of the 2-by-N matrix represents the x- and y-coordinates of points in meters. Each column of the 3-by-N matrix represents the x-, y-, and z-coordinates in meters. Note that the z-coordinate is irrelevant for surface height querying.

• true — Each column of the 2-by-N matrix is the latitude in degrees and longitude in degrees, in the geodetic frame. Each column of the 3-by-N matrix is the latitude in degrees, longitude in degrees, and altitude in degrees, in geodetic coordinates. Note that the latitude is irrelevant for surface height querying.

t — Simulation time

scalar

Simulation time, specified as a scalar.

Dependencies

To enable this argument, select surface as a SeaSurface object.

Data Types: double

Output Arguments

hgt — Height of surface point

scalar | N-element vector of real values

Height of point, returned as a scalar or an N-element vector of real values, where N is the number of queried positions. Units are in meters.

Version History

Introduced in R2022a