Linking two different cue rates in point distance sampling

[Eric Enrique Flores De Gracia]

Dear all,

I am trying to include two different cue.rates into my point distance analysis but failed to do it right.

After including this script the two cue.rates appeared:

cuerate<-unique(datanew2[ ,c("Cue.rate","Cue.rate.SE")])
names(cuerate)<-c("rate","SE")
(mult<-list(creation=cuerate))

    rate   SE
1   1.39 0.20
427 0.97 0.09

But then when trying to obtain the density estimate the following error comes:

Error in dht2_multipliers(multipliers, bigdat) :
  Multirow multipliers need column to link to the data

My link column is season since the two different cue.rates are produced on different seasons, so how can I link this?

Regards,

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Eric Flores De G.

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[Eric Rexstad]

Eric

The data frame you build containing the stratum-specific cue rates and measures of precision need to have an added column containing the name of the stratum to which the stratum-specific cue rate applies.  Here is a toy example using one of the example data sets shipped with the Distance package:

library(Distance)

data(minke)

mult.list <- list(creation=data.frame(Region.Label=c("North", "South"),rate=2, SE=1),

                  decay=data.frame(Region.Label=c("North", "South"), rate=c(0.5, 0.2), SE=c(0.1, 0.05)))

print(mult.list)

fitmod <- ds(minke, key="hr", truncation=1.5)

adjust.mult <- dht2(ddf=fitmod, flatfile = minke, 

                    strat_formula = ~Region.Label, multipliers = mult.list)

Note the "mult.list" object contains two tables, each table with two rows (one for each stratum) as well as three columns: "Region.Label" as well as "rate" and "SE".

All of this said, there is an issue report from May 2025 in our Github repository indicating there is a problem with analyses when there are stratum-specific multipliers.  Have a look at the issue described at this link https://github.com/DistanceDevelopment/Distance/issues/205

Let us know what happens when you add a "Region.Label" to your "cue.rate" data frame. If you encounter an error, I'm afraid you might need to wait for issue #205 to be resolved.

---

From: distance...@googlegroups.com <distance...@googlegroups.com> on behalf of Eric Enrique Flores De Gracia <sai...@gmail.com>
Sent: 02 February 2026 14:57
To: distance...@googlegroups.com <distance...@googlegroups.com>
Subject: [distance-sampling] Linking two different cue rates in point distance sampling

 

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[Eric Enrique Flores De Gracia]

Dear Eric

Thanks for your prompt reply. In fact I came over with the same error

adjust.mult<-dht2(hr.model6,flatfile=datanew2,strat_formula=~Region.Label,ci_width = 0.95,multiplier=mult.list,convert_units=conversion.factor)
Error in ii == "decay" && multipliers[[ii]]$SE != 0 :
  'length = 2' in coercion to 'logical(1)'

So I will try to use the cue rate for my different seasons and estimate a density for each season separately.

Thanks Eric