<html><head><base href="x-msg://158/"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Dear Brenna,</div><div><br></div><div>Yes and no... </div><div><br></div><div>If you do not ask for pseudo-absence (NbPA=0), there is no weigthing and all your pseudo-absence will be used at once. Prevalence = 0.1</div><div>If you add NbPA = 3040 (or more), yes, there is. The prevalence = 0.5</div><div><br></div><div>Does it help?</div><div>Wilfried</div><div><br></div><div><br></div><div><br></div><div><div>Le 22 avr. 2011 à 00:53, Brenna Forester a écrit :</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div ocsi="0" fpstyle="1"><div style="direction: ltr; font-family: Helvetica; color: rgb(0, 0, 0); font-size: 10pt; ">Hello,<br><br>I see in the "Presentation Manual for BIOMOD" (page 18) the following statement: "In all procedures, BIOMOD ensures that the prevalence of the original data is conserved in the calibration and evaluation datasets."<br><br>I have 304 presence records and am running my pseudoabsence pulls with 3040 absences (a prevalence of 0.1). The number of pixels in my study area is 6808.<br><br>From the above quote, I think that BIOMOD is maintaining the original prevalance of 0.1. Is that correct? I just want to be sure that there is no weighting of absence records (e.g. weighting to simulate a prevalence of 0.5).<br><br>Thank you,<br>Brenna<br></div>_______________________________________________<br>Biomod-commits mailing list<br><a href="mailto:Biomod-commits@lists.r-forge.r-project.org">Biomod-commits@lists.r-forge.r-project.org</a><br><a href="https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/biomod-commits">https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/biomod-commits</a><br></div></span></blockquote></div><br><div>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><span class="Apple-style-span" style="font-size: 12px; "><div>--------------------------</div><div>Dr. Wilfried Thuiller</div><div>Laboratoire d'Ecologie Alpine, UMR CNRS 5553</div><div>Université Joseph Fourier</div><div>BP53, 38041 Grenoble cedex 9, France</div><div>tel: +33 (0)4 76 51 44 97</div><div>fax: +33 (0)4 76 51 42 79</div><div><br></div><div>Email: <a href="mailto:wilfried.thuiller@ujf-grenoble.fr">wilfried.thuiller@ujf-grenoble.fr</a><br>Personal website: <a href="http://www.will.chez-alice.fr/">http://www.will.chez-alice.fr</a><br>Team website: <a href="http://www-leca.ujf-grenoble.fr/equipes/emabio.htm">http://www-leca.ujf-grenoble.fr/equipes/emabio.htm</a><br><br>FP6 European MACIS project: <a href="http://www.macis-project.net/">http://www.macis-project.net</a><br>FP6 European EcoChange project: <a href="http://www.ecochange-project.eu/">http://www.ecochange-project.eu</a></div><div><br></div></span></div></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"></span><br class="Apple-interchange-newline">
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