oddsRatio {assignR} R Documentation

## Odds ratio of points or regions

### Description

Calculate ratio of odds for two locations (points or polygons)

### Usage

```oddsRatio(pdR, inputP)
```

### Arguments

 `pdR` RasterStack or RasterBrick of probability density maps, e.g., as produced by `calRaster`. All layers must have common projection. `inputP` SpatialPoints or SpatialPolygons (or *DataFrame equivalent) of length 2

### Examples

```library(sp)

# load North America boundary and global isoscape
data("naMap")
data("d2h_lrNA")

# load hydrogen isotope data for human hair in North America
d = subOrigData(group = "Modern human", mask = naMap, niter = 100)

# rescale from environmental isoscape to tissue isoscape
r = calRaster(known = d, isoscape = d2h_lrNA, mask = naMap)

# four unknown-origin examples
id = c("A", "B", "C", "D")
d2H = c(-110, -90, -105, -102)
un = data.frame(id,d2H)

# assignment
asn = pdRaster(r, unknown = un, mask = naMap)

# SpatialPolygons for two regions of interest
data("states")
s1 = states[states\$STATE_ABBR == "UT",]
s2 = states[states\$STATE_ABBR == "NM",]
plot(naMap)
plot(s1, border = "red", add=TRUE)
plot(s2, border = "blue", add=TRUE)

# Get odds ratio for two regions using SpatialPolygon method
s12 = rbind(s1, s2)
oddsRatio(asn, s12)

# Create SpatialPoints for two points of interest
pp1 = c(-112,40)
pp2 = c(-105,33)
pp12 = SpatialPoints(coords = rbind(pp1,pp2),
proj4string=CRS("+proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0"))
points(pp12, pch = 21, bg = "light blue")

# Get odds ratio for two points using SpatialPoints method
oddsRatio(asn, pp12)
```

[Package assignR version 2.1.0 Index]