ENMTools error

[Anna]

Dear all,
I am trying to run the "model selection" function in ENMtools and I
keep getting the error "Illegal division by zero at
ENMTools_3-17-2011.pl line 2109".
Does anybody have an idea what the problem might be?
Thanks a lot,
Anna

[Anna]

never mind, "problem" fixed
A.

[alaaeldeen80]

Dear Anna,
Merry Christmas.
I have faced the same problem. Would you mind telling to me how did
you solved it?

Thanks in advance.

Alaa

[Shelly]

I realize this is a REALLY old post... but I am having this problem. Can you please post your solution?

Thanks!!

[Shelly]

And to be more specific: I am trying to execute the 'Range Overlap' using the standardized rasters (created with ENMTools).  Does the standardization create 0's? My ascii files are very large and it's unreasonable for me to just take a quick peek at them. I viewed a portion of one grid in ArcGIS and my no data is -9999 in raw format, but 0 in rendered format (could this be a problem?). The ASC files came from my MaxEnt outputs and I have successful used them to execute the Standardization, Correlation, and  Niche Overlap.  Not sure what else to check for.

Thanks for any suggestions!

Shelly

On Wednesday, November 30, 2011 at 10:14:48 AM UTC-5, Anna wrote:

[Dan Warren]

I'm not sure what you mean by "rendered" format, could you clarify?  ENMTools assumes -9999 is the no data value, so if you're reading in a file that has zeroes for no data it's going to get confused and barf.  For what it's worth, you shouldn't have to standardize your rasters before you do any of those analyses anyway, as ENMTools does that on the fly for all of those metrics.

[SJ]

Thanks for you reply Dan! 

My files do have matching extents of -9999 for NoData when they were 1st created as rasters in ArcGIS. When I view a ASCII file in ArcMap with the 'Pixel Inspector' it provides an option to view in "raw" or "rendered" values (I believe the rendered values are just created for the purpose of display, but the 'raw value' should still be the cell VALUE).

So, I guess my question now (if I can get the un-standardized asc's to run) is what number format should be used as a threshold in this analysis? When I view my ASC grids in GIS, it shows me raw values between 1 to 9 (or -9999 for NoData), but I know MaxEnt outputs a probability (so 0.0001 - 0.97, for example).  So, if I wanted the threshold set for the top 1/2 of the probabilities, would I use 0.50 or 5 or something else?

Thanks!

Shelly

~ Shelly

--
You received this message because you are subscribed to a topic in the Google Groups "Maxent" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/maxent/Fzwx-s95lBU/unsubscribe.
To unsubscribe from this group and all its topics, send an email to maxent+un...@googlegroups.com.
To post to this group, send email to max...@googlegroups.com.
Visit this group at http://groups.google.com/group/maxent.
For more options, visit https://groups.google.com/d/optout.

[SJ]

​Also, to add on to my previous reply: is the threshold being applied to the range of values BEFORE or AFTER standardization?  I was assuming it's before, but I'd like to make sure.

For example, comparing the top 60% of the range probabilities for species A with the top 60% of the range of ​probabilities for species B is what I want.(So if the actual probabilities for species A ranged between 0.1 - 0.78, the top 60% of the data would be 0.47 - 0.78 (using the pre-standardized values). So, if the threshold is applied AFTER standardization, I can just set the threshold at 0.6 (correct?).

What I don't want, are the probabilities > 0.60 for species A and probabilities > 0.60 for species B (which is what I am assuming would happen if the threshold is applied BEFORE standardization), resulting in cells between 0.60-0.78 being included for species A, if I entered a value of 0.6. In my mind, it wouldn't make sense to apply the standardization afterwards, but I'd just like to verify.

I hope this makes sense, please let me know if I'm off track...

~ Shelly

[Dan Warren]

Can you just open one of the .asc files in a text editor and look at it there?  I have no idea what ArcGIS is doing, but ENMTools is just reading it in as a text file.  As for the rest of it, I'm not entirely clear on what you're saying; ENMTools doesn't apply any sort of threshold as part of the AIC calculation or standardization.