interp

Interpolate RF propagation data

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Syntax

interpvalue = interp(pd,lat,lon)
interpvalue = interp(pd,Name=Value)

Description

interpvalue = interp(pd,lat,lon) returns interpolated values of the specified propagation data object at the specified query points. The function performs the interpolation using a scattered data interpolation method.

example

interpvalue = interp(pd,Name=Value) specifies options using name-value arguments.

Examples

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Open Live Script

Define names and locations of sites around Boston.

names = ["Fenway Park","Faneuil Hall","Bunker Hill Monument"];
lats = [42.3467,42.3598,42.3763];
lons = [-71.0972,-71.0545,-71.0611];

Create array of transmitter sites.

txs = txsite("Name", names,...
       "Latitude",lats,...
       "Longitude",lons, ...
       "TransmitterFrequency",2.5e9);

Compute received power data for each transmitter site.

maxr = 20000;
pd1 = coverage(txs(1),"MaxRange",maxr);
pd2 = coverage(txs(2),"MaxRange",maxr);
pd3 = coverage(txs(3),"MaxRange",maxr);

Compute rectangle containing locations of all data.

locs = [location(pd1); location(pd2); location(pd3)];
[minlatlon, maxlatlon] = bounds(locs);

Create grid of locations over rectangle.

gridlength = 300;
latv = linspace(minlatlon(1),maxlatlon(1),gridlength);
lonv = linspace(minlatlon(2),maxlatlon(2),gridlength);
[lons,lats] = meshgrid(lonv,latv);
lats = lats(:);
lons = lons(:);

Get data for each transmitter at grid locations using interpolation.

v1 = interp(pd1,lats,lons);
v2 = interp(pd2,lats,lons);
v3 = interp(pd3,lats,lons);

Create propagation data containing minimum received power values.

minReceivedPower = min([v1 v2 v3],[],2,"includenan");
pd = propagationData(lats,lons,"MinReceivedPower",minReceivedPower);

Plot minimum received power, which shows the weakest signal received from any transmitter site. The area shown may correspond to the service area of triangulation using the three transmitter sites.

sensitivity = -110;
contour(pd,"Levels",sensitivity:-5,"Type","power")

Input Arguments

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Propagation data, specified as a propagationData object.

Latitude coordinate in degrees, specified as a vector with elements in the range [–90, 90]. The function assumes that the coordinates are referenced to the World Geodetic System of 1984 (WGS 84) reference ellipsoid.

Longitude coordinates in degrees, specified as a vector. The function assumes that the coordinates are referenced to the WGS 84 reference ellipsoid.

Name-Value Arguments

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Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: interp(pd,lat,lon,Method="linear") calculates the interpolated values using a linear interpolation method.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: interp(pd,lat,lon,"Method","linear") calculates the interpolated values using a linear interpolation method.

Data variable to interpolate, specified as a character vector or string scalar. The data variable must correspond to a variable name of the table used to create the propagationData object.

The default value is the DataVariableName property of the specified propagationData object.

Data Types: char | string

Method used to interpolate the data, specified as one of these options:

  • "natural" — Natural neighbor (Sibson) interpolation.

  • "linear" — Linear interpolation.

  • "nearest" — Nearest neighbor interpolation.

Data Types: char | string

Output Arguments

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Interpolated values from the propagation data, returned as a vector. The number of elements in interpvalue matches the number of elements in lat and lon.

When you specify query points that are outside of the data region, the corresponding interpolated values are NaN values.

Version History

Introduced in R2020a

See Also

Functions

Objects