Ciao Pierluigi, On Thu, Feb 28, 2013 at 12:17 PM, Ing. Pierluigi De Rosa < [email protected]> wrote:
> Dear All, > I should calculate the area of the hillslope per unit contour length. > The drainage area per unit contour length (specific catchment area), can be calculated by multiplying the upslope area obtained by r.watershed (flow accumulation) per the cell grid size (as contour length). HTH, madi > I saw r.topidx calculate topographic index (wetness index), > ln(a/tan(beta)), map from elevation map where > a: the area of the hillslope per unit contour length that drains through > any point, > tan(beta): the local surface topographic slope (delta vertical) / (delta > horizontal). > > I should only have the numerator of topographic index. How can i get it? > Thanks > Pierluigi > > -- > > > ________________________________________________________________________ > Ing. Pierluigi De Rosa (PhD) > Studio Associato GFOSSERVICES > > Via Tilli 58 - 06127 Perugia (PG) > tel: 075 7825101 / fax: 075 7823038 > cel: 3497558268 > web: www.gfosservices.it > skype: pierluigi.derosa > > _______________________________________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user > -- Margherita DI LEO Postdoctoral Researcher European Commission - DG JRC Institute for Environment and Sustainability (IES). Unit H03 – FRC Via Fermi, 2749 I-21027 Ispra (VA) - Italy - TP 261 Tel. +39 0332 78 3600 [email protected] Disclaimer: The views expressed are purely those of the writer and may not in any circumstance be regarded as stating an official position of the European Commission.
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