[R-sig-Geo] Converting spatialPointsDataFrame into ppp

GodinA godina at dal.ca
Sun Sep 18 02:16:13 CEST 2011

Thank you very much for this quick reply Dr. Bivand.
I am taking good notes of your suggestions.

I'm a little concern about your comments that my data are not a marked point
process and would like to verify with you a few points. You are correct that
my points - the catch positions are essentially fishermen decisions.
However, I am using at-sea observer data, which are (technically) random
sampling of a subset of all fishing effort (usually between 5-15
percent/year, although it varies between years, fisheries, and regions). As
a starting point, I would like to reproduce what Gardner et al. (2008) have
done. [Gardner B, Sullivan PJ, Morreale SJ, Epperly SP. Spatial and temporal
statistical analysis of bycatch data: patterns of sea turtle bycatch in the
North Atlantic. Canadian Journal of Fisheries and Aquatic Sciences.
2008;65(11):2461-2470. Available from:
However, my data are somewhat more complex since I am dealing with different
fishing gears (over 15 types) over the spend of 15 years (1995-2010). I
would like to go beyond describing the space-time clustering of catch events
and try to model these events to oceanographical variables, such as
temperature and ocean-color derived chlorophyll concentration.

I would be grateful for any of your thoughts, comments, and/or suggestions. 
Thank you very much for your time,


Aurelie Cosandey-Godin
Ph.D. Candidate, Department of Biology
Industrial Graduate Fellow, WWF-Canada

Dalhousie University | Biology Dept. |Halifax, NS, Canada 
Email: godina at dal.ca | Web: wormlab.biology.dal.ca
Want to learn more about sharks in Atlantic Canada? Visit ShARCC! www.atlanticsharks.org
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