r.northerness.easterness

r.northerness.easterness - Calculation of northerness, easterness and the interaction between northerness and slope - GRASS GIS addon

NAME r.northerness.easterness - Calculation of northerness, easterness and the interaction between northerness and slope

KEYWORDS raster, terrain, aspect, slope, sun

SYNOPSIS r.northerness.easterness r.northerness.easterness --help r.northerness.easterness elevation=name [--help] [--verbose] [--quiet] [--ui] Flags:

--help Print usage summary --verbose Verbose module output --quiet Quiet module output --ui Force launching GUI dialog

Parameters:

elevation=name [required] Name of elevation raster map

DESCRIPTION r.northerness.easterness calculates northerness, easterness and the interaction between northerness and slope (northerness*slope). The user must specify the input elevation raster map.

NOTES As aspect is a circular land-surface parameter, in ecology a sine or cosine transformation is often used to obtain a continuous gradient, stressing the north-south or east-west gradient (northness or eastness).

The GRASS GIS default aspect angles (cartesian) are converted to compass angles.

Calculated raster maps are:

northerness: cos(aspect)
easterness: sin(aspect)
interaction between northerness and slope: northerness*slope

The color of these raster maps are set to grey. EXAMPLE

align region to DEM and habitat vector

g.region -a raster=DEM align=DEM

run r.northerness.easterness

r.northerness.easterness elevation=DEM

SEE ALSO r.mapcalc, r.slope.aspect

REFERENCES Olaya, V. 2009. Basic Land-Surface Parameters. In: Hengl, T. & Reuter, H.I. (eds.) 2009. Geomorphometry. Concepts, Software, Applications. Developments in Soil Science, Volume 33. Elsevier.

AUTHOR Helmut Kudrnovsky