Warning: Sample at ... in presence is missing some environmental data

[Michael Smith]

Hi all,

I'm running MaxEnt from dismo (the R package) and have been getting warning messages:

Warning: Sample at 40.0, 40.0 in presence is missing some environmental data (e.g. stacked_env_variables.20)

Should I be worried that the sample number is repeated? I assume this is one of the presence records and one of the layers of the raster stack is NA at that spatial point?

Thanks,

Michael

[Bede-Fazekas Ákos]

Hello Michael,
if the number of such warning messages is low, you can ignore them. If it is high, then numerous presence points are removed from the model training, which will decrease the goodness of your model. (If the number is very high, it might indicate that your rasters are wrong, e.g. the projection is not OK.)
Also you can set the "allowpartialdata" parameter to TRUE to use this sample point as well.
HTH,
Ákos

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[Michael Smith]

Thanks! I now realise that "40, 40" refers to the 40th presence record and has nothing to do with coordinates.

I've been running a 'null model' 100 times for every species model tested, using random points instead of the genuine presence records, so I will try this again with the allowpartialdata parameter set to TRUE as otherwise, perhaps my null model appears worse than it should.

[Bede-Fazekas Ákos]

Hello,
Yes, 40 is no a coordinate...
Setting allowpartialdata to TRUE will let you include this presence point only if least one environmental layer/variable is known at this point. If all variables are unknown, MaxEnt will continue to remove this point from the analysis.
Have a nice weekend,
Ákos

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