Hi Moritz, thank you for your reply,
On Wed, Jan 23, 2013 at 12:21 PM, Moritz Lennert < mlenn...@club.worldonline.be> wrote: > >> If we call WIND the direction map which uses the convention degrees >> clockwise from North, and GRASS the output map, the rule that I applied >> is: >> >> IF 0 <= WIND < 270 ; GRASS = 270 - WIND >> IF WIND = 270 ; GRASS = 360 >> IF 270 < WIND < 360 ; GRASS 630 - 0 >> IF WIND = null ; GRASS = 0 >> NULL otherwise (this latter I have added to check if there is any error. >> > > This is not correct. > > WIND = 0 means North. Actually this was tricky also for me, but: Wind direction is measured in: - degrees clockwise from uphill (direction the wind is pushing the fire) - degrees clockwise from North (direction the wind is blowing from) If the wind is blowing FROM north, it means that the arrow is TOWARDS south.. Am I wrong? -- 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 margherita.di-...@jrc.ec.europa.eu 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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