# sunpos: Azimuth and zenith of the Sun In insol: Solar Radiation

## Description

Returns a matrix of azimuth and zenith angles of the sun given the unit vectors from the observer to the direction of the sun.

## Usage

 `1` ```sunpos(sunv) ```

## Arguments

 `sunv` coordinates x, y, z of the unit vector in the direction of the sun.

## Value

A matrix of azimuth and zenith angles.

## Author(s)

Javier G. Corripio

## References

Corripio, J. G.: 2003, Vectorial algebra algorithms for calculating terrain parameters from DEMs and the position of the sun for solar radiation modelling in mountainous terrain, International Journal of Geographical Information Science 17(1), 1-23.

`sunvector`,

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23``` ```## Julian Day hourly intervals at spring equinox jd = JD(seq(ISOdate(2019,3,20,0),ISOdate(2019,3,20,23),by="hour")) ## sun position sp = sunpos(sunvector(jd,46.813,9.844,1)) ## daylight zenith<=90 sp = sp[which(sp[,2]<=90),] ## Plot the apparent solar path at Davos on the spring equinox ramp = colorRamp(c("red", "orange","yellow")) crmp = c(rgb(ramp(seq(1/6,1,1/6)), max = 255),rgb(ramp(seq(1,1/6,-1/6)), max = 255)) plot(sp[,1],90-sp[,2],xlab='Azimuth', ylab='Elevation',main='Apparent solar path at Davos on the spring equinox', pch=20,col=crmp,cex=(300-sp[,2])/90) ## Not run: require(plotrix) polar.plot(90-sp[,2],sp[,1],start=90,clockwise=TRUE,rp.type='s', point.symbols=20,point.col=2,cex=2,radial.lim=c(0,90), main='Apparent solar path at Davos on the spring equinox') ## End(Not run) ```

### Example output

```Loading required package: plotrix
```

insol documentation built on Jan. 16, 2019, 5:04 p.m.