<html><body><div><span class="Apple-style-span" style="white-space: pre;">Dear all, </span></div><div><span class="Apple-style-span" style="white-space: pre;"><br></span></div><div><span class="Apple-style-span" style="white-space: pre;">I'm working with function 'ppm' in pkg: spatstat; the aim is to fit </span><span class="Apple-style-span" style="white-space: pre; ">IPP (inhomogeneous pt process) model to a point pattern.</span></div><div><span class="Apple-style-span" style="white-space: pre; ">It's worked well before, but recently have tried it with an additional covariate -- spatially referenced and stored as an image object.</span></div><div><pre style="font-family: Helvetica,Arial,sans-serif; font-size: 13px" _mce_style="font-family: Helvetica,Arial,sans-serif; font-size: 13px;">When I go to run the inhom point process model, the following warning appears. 'B10' is my point pattern object, 'flightPix' is the spatial covariate image object.</pre><pre style="font-family: Helvetica,Arial,sans-serif; font-size: 13px" _mce_style="font-family: Helvetica,Arial,sans-serif; font-size: 13px;"><br></pre><pre style="font-family: Helvetica,Arial,sans-serif; font-size: 13px" _mce_style="font-family: Helvetica,Arial,sans-serif; font-size: 13px;">> Q <- ppm(B10, ~flights, covariates = list(flights = flightPix))
Warning message:
Values of the covariate ‘flights’ were NA or undefined at 0.08% (2 out of 2493) of the quadrature points. Occurred while executing: ppm(B10, ~flights, covariates = list(flights = flightPix)) </pre><pre style="font-family: Helvetica,Arial,sans-serif; font-size: 13px" _mce_style="font-family: Helvetica,Arial,sans-serif; font-size: 13px;"><br></pre><pre style="font-family: Helvetica,Arial,sans-serif; font-size: 13px" _mce_style="font-family: Helvetica,Arial,sans-serif; font-size: 13px;"># then when I look at summary output for the IPP model, it says:</pre><pre style="font-family: Helvetica,Arial,sans-serif; font-size: 13px" _mce_style="font-family: Helvetica,Arial,sans-serif; font-size: 13px;">Problem:
Values of the covariate ‘flights’ were NA or undefined at 0.08% (2 out of 2493) of the quadrature points </pre><pre style="font-family: Helvetica,Arial,sans-serif; font-size: 13px" _mce_style="font-family: Helvetica,Arial,sans-serif; font-size: 13px;"><br></pre><pre style="font-family: Helvetica,Arial,sans-serif; font-size: 13px" _mce_style="font-family: Helvetica,Arial,sans-serif; font-size: 13px;">Is there a way solve this problem? Thanks for any help!!</pre><pre style="font-family: Helvetica,Arial,sans-serif; font-size: 13px" _mce_style="font-family: Helvetica,Arial,sans-serif; font-size: 13px;">Robin</pre><pre style="font-family: Helvetica,Arial,sans-serif; font-size: 13px" _mce_style="font-family: Helvetica,Arial,sans-serif; font-size: 13px;">-------------</pre><pre style="font-family: Helvetica,Arial,sans-serif; font-size: 13px" _mce_style="font-family: Helvetica,Arial,sans-serif; font-size: 13px;"><span class="Apple-style-span" style="font-family: Helvetica, Arial, Verdana, sans-serif; white-space: normal; "><pre style="white-space: pre-wrap !important; word-wrap: normal !important; font: normal normal normal 13px/normal Helvetica, Arial, Verdana, sans-serif; font-family: Helvetica, Arial, sans-serif; font-size: 13px; ">Department of Biology
University of New Brunswick
Fredericton, NB
Canada </pre></span></pre></div><div><br></div></body></html>