Category Archives: Data manipulation

The elevation of Lake Tilo

For my PhD, I studied the palaeolimnology of two lakes in the Ethiopian rift valley, using diatoms to reconstruct changes in the water chemistry of Lake Awassa, an oligosaline caldera lake which retains its low salinity despite having no effluent … Continue reading

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Merging taxa in assemblage data

One possible reason for the impossible percent values I’ve found in assemblages data is that taxa have been merged in Excel after percent were calculated. Doing anything in Excel is to invite disaster, if nothing else, it is very difficult … Continue reading

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How many is fifty? Sanity checks for assemblage data.

This week I’m at the Palaeolimnology Symposium in Stockholm this week. I have a couple of presentations. I gave the first this morning to the chironomid “DeadHead” meeting. I showed some sanity checks for assemblage data, some of which are … Continue reading

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Statigraphic diagrams with ggplot

rioja::strat.plot is a great tool for plotting stratigraphic plots in R, but sometimes it is not obvious how to do something I want, perhaps a summary panel showing the percent trees/shrubs/herbs. Of course, I could extend strat.plot, but I do … Continue reading

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How to calculate percent from counts in R

Micropaleontologists and others often want to calculate percent from count data. From looking at archived data, I realise that what should be an easy process goes wrong far more often that it should (which is of course never). Yesterday, I … Continue reading

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All the pollen

“And some things that should not have been forgotten were lost. History became legend. Legend became myth. And for two and a half thousand years, the metadata passed out of all knowledge.” A couple of months ago, Eric Grimm gave … Continue reading

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