r.param.scale(1)       Grass User's Manual	 r.param.scale(1)



NNAAMMEE
       rr..ppaarraamm..ssccaallee - GRASS module that extracts terrain parame-
       ters from a DEM. Uses a multi-scale approach by fitting	a
       bivariate  quadratic  polynomial  to  a	given window size
       using least squares.

UUssaaggee::
       rr..ppaarraamm..ssccaallee   [-c]   iinn==name	oouutt==name    [ss__ttooll==value]
       [cc__ttooll==value]	[ssiizzee==value]   [ppaarraamm==name]   [eexxpp==value]
       [zzssccaallee==value]



FFllaaggss::
       -c Constrain model through central window cell

PPaarraammeetteerrss::
	iinn Input elevation raster

	oouutt Output raster representing the selected  morphometric
       parameter

	ss__ttooll  Slope  tolerance  that  defines	a  `flat' surface
       (degrees)

       default: 1.0

	cc__ttooll Curvature tolerance that defines `planar' surface

       default: 0.02

	ssiizzee Size of processing window (odd numbers only)

       default: 3

	ppaarraamm Morphometric parameter to calculate

       options:
       elev,slope,aspect,profc,planc,longc,crosc,minic,maxic,
       feature

       default: elev

	eexxpp Exponent for distance weighting (0.0-4.0)

       default: 0.0

	zzssccaallee Vertical scaling factor

       default: 1.0



       The module calculates the following parameters  (terminol-
       ogy is from Wood, 1996 with related terminology

       used in other GRASS modules listed in brackets)

		     elev:   Generalised   elevation  value  (for
		     resampling purposes at different scale)

		     slope:   Magnitude   of   maximum	 gradient
		     (steepest slope angle)

		     aspect:   Direction   of	maximum  gradient
		     (steepest slope direction=flow direction)

		     _p_r_o_f_c or profile curvature (curvature inter-
		     secting with the plane defined by _Z axis and
		     maximum gradient direction)

		     _p_l_a_n_c or plan curvature  (horizontal  curva-
		     ture, intersecting with the _X_Y plane)

		     _l_o_n_g_c  or	longitudinal  curvature  (profile
		     curvature	intersecting   with   the   plane
		     defined  by  the  surface normal and maximum
		     gradient direction)

		     _c_r_o_s_c or cross-sectional curvature  (tangen-
		     tial  curvature  intersecting with the plane
		     defined by the surface normal and a  tangent
		     to  the  contour  - perpendicular to maximum
		     gradient direction)

		     _m_a_x_i_c or maximum curvature (can  be  in  any
		     direction)

		     _m_i_n_i_c  or	minimum  curvature  (in direction
		     perpendicular to the direction of of maximum
		     curvature)

		     _m_e_a_n_c  or mean curvature (average of maximum
		     and minimum curvatures).

		     Morphometric   features:	peaks,	  ridges,
		     passes, channels, pits and planes

NNOOTTEESS
       In  _r_._p_a_r_a_m_._s_c_a_l_e  the direction of maximum gradient (con-
       sidered downslope) is stored as:

		     0..+180 degree from West to North to East

		     0..-180 degree from West to South to East
       Note that the aspect map is  calculated	differently  from
       r.slope.aspect.

SSttiillll ttoo ddoo
       Fix  bug  when  `constrain  through  central  cell' option
       selected.  Create  color  tables  for  all  output   files
       (presently only on features).



SSEEEE AALLSSOO
       _d_._p_a_r_a_m_._s_c_a_l_e

       See  also  Java	Code in LandSerf that implements the same
       procedure



RREEFFEERREENNCCEE
       Wood, J. (1996): The Geomorphological characterisation  of
       Digital	Elevation Models. Diss., Department of Geography,
       University of Leicester, U.K.

       online at:

       www.geog.le.ac.uk/jwo/research/dem_char/thesis/index.html

AAUUTTHHOORR
       ASSIST's home

       Update to FP 3/2002: L. Potrich, M.  Neteler,  S.  Menegon
       (ITC-irst)

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_0_3_/_2_9 _0_9_:_2_5_:_2_3 _$



GRASS 5.0					 r.param.scale(1)
