gmcgrath
commented
11 years ago Hi Nanu, I did have a little success with using a 2D fourier transform to assess wavelength and orientation. If you end up with an intrinsic wavelength but no preferred orientation then you likely have spots or holes. There are a few papers which have implemented similar approaches. Here are a couple:
Deblauwe, V., P. Couteron, J. Bogaert, and N. Barbier (2012), Determinants and dynamics of banded vegetation pattern migration in arid climates, Ecol. Monog., 82(1), 3–21.
and
Local properties of patterned vegetation: quantifying endogenous and exogenous effects
Authors:G.G. Pennyhttp://arxiv.org/find/nlin/1/au:+Penny_G/0/1/0/all/0/1, K.E. Danielshttp://arxiv.org/find/nlin/1/au:+Daniels_K/0/1/0/all/0/1, S.E. Thompsonhttp://arxiv.org/find/nlin/1/au:+Thompson_S/0/1/0/all/0/1 (Submitted on 18 Mar 2013) Abstract: Dryland ecosystems commonly exhibit periodic bands of vegetation, thought to form due to competition between individual plants for heterogeneously distributed water. In this paper, we develop a Fourier method for locally identifying the pattern wavenumber and orientation, and apply it to aerial images from a region of vegetation patterning near Fort Stockton, Texas. We find that the local pattern wavelength and orientation are typically coherent, but exhibit both rapid and gradual variation driven by changes in hillslope gradient and orientation, the potential for water accumulation, or soil type. Endogenous pattern dynamics, when simulated for spatially homogeneous topographic and vegetation conditions, predict pattern properties that are much less variable than the orientation and wavelength observed in natural systems. Our local pattern analysis, combined with ancillary datasets describing soil and topographic variation, highlights a largely unexplored correlation between soil depth, pattern coherence, vegetation cover and pattern wavelength. It also, surprisingly, suggests that downslope accumulation of water may play a role in changing vegetation pattern properties. Subjects: Pattern Formation and Solitons (nlin.PS); Populations and Evolution (q-bio.PE) Cite as: arXiv:1303.4360http://arxiv.org/abs/1303.4360 [nlin.PS] (or arXiv:1303.4360v1http://arxiv.org/abs/1303.4360v1 [nlin.PS] for this version
From: nanu [notifications@github.com] Sent: 23 April 2013 20:07 To: n-dim/ecohydraulical-feedback Subject: [ecohydraulical-feedback] simulation seems to not work with non-square grids (#18)
— Reply to this email directly or view it on GitHubhttps://github.com/n-dim/ecohydraulical-feedback/issues/18.
If you mean that m does not equal n then yes you are right. Have to trace through the size of array definitions in subroutines. May also have to check that when randomly selecting coordinate pairs that the combinations permits all possible pairs (unlikely). I'll have a look tomorrow. By the way how are you going with your modelling? Gavan
From: nanu [notifications@github.com] Sent: 23 April 2013 20:07 To: n-dim/ecohydraulical-feedback Subject: [ecohydraulical-feedback] simulation seems to not work with non-square grids (#18)
— Reply to this email directly or view it on GitHubhttps://github.com/n-dim/ecohydraulical-feedback/issues/18.