density for each transect?

[M Borja]

Hi, good morning to every one.

I have just joined this group.

I saw in a Table of a paper that a calculation of density appeared for each of the transects performed for different species.

Can this be obtained using Distance software?

Thanks in advance

 M. Molina

[Eric Rexstad]

Greetings and welcome to the list.

Can you clarify what you mean by "Distance software"? We have a stand-alone program that runs under the Windows operating system. But we also have an R package called "Distance".

Using the R package, one of the components of the fitted model object coming from the "ds()" function is something called "bysample"

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From: distance...@googlegroups.com <distance...@googlegroups.com> on behalf of M Borja <moli...@gmail.com>
Sent: 02 May 2025 08:34
To: distance-sampling <distance...@googlegroups.com>
Subject: [distance-sampling] density for each transect?

 

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[Eric Rexstad]

I wasn't quite finished with the previous email:

Greetings and welcome to the list.

Can you clarify what you mean by "Distance software"? We have a stand-alone program that runs under the Windows operating system. But we also have an R package called "Distance".

Using the R package, one of the components of the fitted model object coming from the "ds()" function is something called "bysample"

library(Distance)

data(ducknest)

cu <- convert_units("meter", "kilometer", "square kilometer")

result <- ds(data=ducknest, key="hn", convert_units = cu)

print(head(result$dht$individuals$bysample))

 Region Sample Effort Sample.Area  Area  n     Nhat    Nchat     Dhat
Default      1 128.75       12.36 12.36 27 31.05775 31.05775 2.512763
Default     10 128.75       12.36 12.36 17 19.55488 19.55488 1.582110
Default     11 128.75       12.36 12.36 25 28.75718 28.75718 2.326633
Default     12 128.75       12.36 12.36 20 23.00574 23.00574 1.861306
Default     13 128.75       12.36 12.36 22 25.30632 25.30632 2.047437
Default     14 128.75       12.36 12.36 26 29.90747 29.90747 2.419698

Using Distance for Windows, you might be able to obtain similar estimates by transect using this specification for the model definition

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From: Eric Rexstad <Eric.R...@st-andrews.ac.uk>
Sent: 03 May 2025 18:48
To: M Borja <moli...@gmail.com>; distance-sampling <distance...@googlegroups.com>
Subject: Re: [distance-sampling] density for each transect?