All New Content https://www.r4photobiology.info/all-content.html Web site R, data analysis and photobiology. It includes a blog, web pages and galleries of R code examples and other resources. quarto-1.9.29 Thu, 23 Apr 2026 21:00:00 GMT Contents: R examples Galleries https://www.r4photobiology.info/galleries.html https://www.r4photobiology.info/galleries.html Thu, 23 Apr 2026 21:00:00 GMT Guided Tour: Statistical Plot Annotations Pedro J. Aphalo https://www.r4photobiology.info/ggpp-ggpmisc-index.html Package ‘ggplot2’ documentation ]]> ggpp ggpmisc R plotting https://www.r4photobiology.info/ggpp-ggpmisc-index.html Thu, 23 Apr 2026 21:00:00 GMT Home Page https://www.r4photobiology.info/ If you are interested in the R language, data visualization, data analysis, the daylight spectrum, measurement of light and optical properties or in how plants perceive and respond to the characteristics of the light environment in which they grow, you are likely to find something of interest among the more than a hundred pages and posts at this site. ]]> https://www.r4photobiology.info/ Thu, 23 Apr 2026 21:00:00 GMT Contents: Pages Section https://www.r4photobiology.info/pages.html
Last edited First published Title Subtitle Reading Time
2026-04-23 2024-07-13 R Packages: Timeline of Updates Packages published in CRAN that I maintain 3 min
2026-04-23 2022-12-17 Geometries geom_text_s() and geom_label_s() ggpp: Grammar Extensions to ‘ggplot2’ 11 min
2026-04-22 2023-02-28 Packages ‘ggpmisc’, ‘ggpp’ and ‘gginnards’ Data labels, annotations and insets for ‘ggplot2’ 18 min
2026-04-21 2023-05-03 ‘ggplot2’ Basics The Layered Grammar of Graphics 17 min
2026-02-02 2023-04-27 ‘ooacquire’: Spectral Irradiance Measurement Tutorial and Description of the UI of acq_irrad_interactive() 49 min
2025-08-12 2023-03-20 OmniDriver, Java and the whims of companies Open source alternative drivers 6 min
2025-03-30 2023-02-19 The R for Photobiology Suite Photobiology-related computations in R 14 min
2025-01-24 2025-01-23 Introduction to Mixed Effects Models Concepts and examples in R with package ‘nlme’ 19 min
2024-03-06 2024-03-06 Plotting circular data with ‘ggplot2’   5 min
2024-02-10 2023-03-04 R Packages Status and downloads at R Universe 1 min
2024-01-19 2024-01-13 ‘ooacquire’: Spectral Irradiance Algorithms Corrections for enhanced dynamic range 55 min
2023-11-30 2023-11-27 Linear Models An introduction using lm() 15 min
2023-11-30 2023-11-30 Alternative approaches Robust, quantile and major axis regression 2 min
2023-11-27 2023-05-30 Randomization and independent replicates Restricted randomization in design of experiments 10 min
2023-11-27 2023-05-30 Model fitting in R An introduction to lm(), glm() and nls() 15 min
2023-11-21 2023-11-21 Theoretical probability distributions Interactive applications using R package Shiny 1 min
2023-11-18 2023-11-18 Flow of code execution R language constructs for flow control 9 min
2023-10-28 2023-09-19 R at its simplest R vs. calculator vs. Excel 6 min
2023-10-21 2023-10-21 Design of Experiments Principles and practice 10 min
2023-10-19 2023-08-19 Research as a process Design, realization, data analysis, and communication of research 31 min
2023-07-27 2023-05-24 EDA with ‘ggplot2’ EDA = Exploratory Data Analysis 20 min
2023-02-20 2023-02-20 A handbook of best practice in plant UV photobiology   1 min
Invalid Date 2022-08-24 Learn R: As a Language News 2 min
2023-08-07 2023-02-20 Handbook on photobiological calculations with R   2 min
2023-06-29 2023-02-18 R, RStudio and Quarto Installation and updates 6 min
2023-05-13 2023-05-03 Markdown Basics (PARTIAL DRAFT) Text mark up vs. visual editors 2 min
2023-05-10 2023-04-27 Spectral fluorescence with ‘ooacquire’ Tools: reflectance probe and LED 7 min
2023-02-21 2016-09-15 For those interested in optical properties   1 min
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]]> https://www.r4photobiology.info/pages.html Thu, 23 Apr 2026 21:00:00 GMT Contents: R Blog https://www.r4photobiology.info/posts.html
Edited Published Title Subtitle Reading Time
2025-01-23 2024-05-16 Is this a polynomial? Computing on the R langauge 4 min
2024-04-30 2024-04-30 Learn R: As a Language 2ed Published on 2024-04-26 1 min
2024-02-10 2024-02-10 Repository migrated to R-Universe Updated installation instructions 1 min
2024-08-24 2023-10-21 photobiology 0.11.x Most significant recent changes 2 min
2024-08-24 2023-06-10 ooacquire >= 0.4.0 ooacquire: Acquire Data from OO Spectrometers 4 min
2023-06-11 2023-05-28 photobiology 0.10.1x Most significant recent changes 4 min
2023-05-21 2023-05-21 I have started using Mastodon… …to announce new releases of my R packages 1 min
2023-05-10 2023-04-10 ooacquire 0.3.x ooacquire: Acquire Data from OO Spectrometers 8 min
2023-03-29 2023-02-27 Website migrated to Quarto   2 min
2023-10-21 2023-02-03 ggspectra >= 0.3.10   2 min
2023-01-05 2023-01-05 photobiology 0.10.15   2 min
2023-01-05 2023-01-05 photobiologyWavebands 0.5.1   3 min
2024-06-27 2022-12-05 ggpp >= 0.5.0 updates ggpp: Grammar Extensions to ‘ggplot2’ 3 min
2022-10-18 2022-10-18 ooacquire 0.2.6   2 min
2024-04-07 2022-10-15 gginnards >= 0.1.1 updates gginnards: Explore the Innards of ‘ggplot2’ Objects 1 min
2022-10-15 2022-10-15 ggspectra 0.3.9   2 min
2022-10-15 2022-10-15 photobiology 0.10.14   1 min
2023-07-25 2022-10-15 photobiologyInOut 0.4.25/0.4.26/0.4.27   2 min
2022-10-15 2022-10-15 An R marathon updating packages   4 min
2022-10-05 2022-10-05 photobiology 0.10.13   2 min
2022-10-01 2022-10-01 ooacquire 0.2.4 and 0.2.5   3 min
2022-09-30 2022-09-30 ggpp 0.4.5   2 min
2022-08-13 2022-08-13 photobiologyWavebands 0.5.0   1 min
2022-08-13 2022-08-13 HTML5 compliance of R packages   1 min
2024-04-07 2022-08-05 ggpmisc >= 0.5.0 updates ggpmisc: Miscellaneous Extensions to ‘ggplot2’ 2 min
2022-07-23 2022-07-23 photobiology 0.10.12   3 min
2022-07-10 2022-07-10 photobiology 0.10.11   2 min
2022-06-15 2022-06-15 ggpmisc 0.4.7   3 min
2022-05-15 2022-05-15 photobiologyInOut 0.4.24   1 min
2022-05-14 2022-05-14 photobiologyLEDs 0.5.0   2 min
2022-04-29 2022-04-29 R 4.2.0   1 min
2022-04-16 2022-04-16 ggspectra 0.3.8   3 min
2020-07-12 2020-07-12 Performance of package ‘photobiology’   2 min
2019-04-24 2019-04-24 Benchmarking function sun_angles()   8 min
2019-02-22 2019-02-22 Yoctopuce modules: Spectrometer   6 min
2019-02-21 2019-02-21 Yoctopuce modules: Introduction   2 min
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]]> https://www.r4photobiology.info/posts.html Thu, 23 Apr 2026 21:00:00 GMT Contents: Presentations https://www.r4photobiology.info/presentations.html
Published Edited Title Subtitle Reading Time
2026-04-12 2026-04-12 R for Photobiology Difficult Computations Made Easy 9 min
2024-05-28 2024-05-28 Looking back 40 years Research into environmental sensing and acclimation 6 min
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]]> https://www.r4photobiology.info/presentations.html Thu, 23 Apr 2026 21:00:00 GMT Contents: R and R packages Pedro J. Aphalo https://www.r4photobiology.info/r-index.html packages which can be locally installed in a library. ]]> https://www.r4photobiology.info/r-index.html Thu, 23 Apr 2026 21:00:00 GMT Contents: SenPEP Blog https://www.r4photobiology.info/senpep-posts.html https://blogs.helsinki.fi/senpep-blog/. Please, open the collapsed callouts below for additional information. ]]> contents listing https://www.r4photobiology.info/senpep-posts.html Thu, 23 Apr 2026 21:00:00 GMT Pedro J. Aphalo https://www.r4photobiology.info/presentations/r4p-caas-2026.html slides from talk R r4photobiology https://www.r4photobiology.info/presentations/r4p-caas-2026.html Sat, 11 Apr 2026 21:00:00 GMT Visit to CAAS Beijing Pedro J. Aphalo https://www.r4photobiology.info/senpep-posts/caas-visit-2025.html travel China CAAS https://www.r4photobiology.info/senpep-posts/caas-visit-2025.html Sat, 10 Jan 2026 22:00:00 GMT Digital light sensors Pedro J. Aphalo https://www.r4photobiology.info/senpep-posts/spectral-sensors.html measurement and control https://www.r4photobiology.info/senpep-posts/spectral-sensors.html Mon, 18 Aug 2025 21:00:00 GMT Animated plots of spectra Pedro J. Apahlo https://www.r4photobiology.info/galleries/photobiology/animated-plots-of-spectra.html Animated plots of spectral data included in the on-line documentation of R package ‘ggspectra’ version >= 0.3.16. ]]> photobiology r4photobiology R examples https://www.r4photobiology.info/galleries/photobiology/animated-plots-of-spectra.html Sat, 15 Feb 2025 22:00:00 GMT Introduction to Mixed Effects Models Pedro J. Aphalo https://www.r4photobiology.info/pages/mixed-effects-models-intro.html R model fitting https://www.r4photobiology.info/pages/mixed-effects-models-intro.html Wed, 22 Jan 2025 22:00:00 GMT R Packages: Timeline of Updates Pedro J. Aphalo https://www.r4photobiology.info/pages/CRAN-activity.html CRAN. The total number of packages submissions to CRAN (mostly updates) as author and maintainer is 244 since 2016-01-29. The most recent of these updates was published in CRAN on 2026-03-23. ]]> R packages https://www.r4photobiology.info/pages/CRAN-activity.html Fri, 12 Jul 2024 21:00:00 GMT Multichannel LED arrays Pedro J. Aphalo https://www.r4photobiology.info/senpep-posts/led-arrays.html measurement and control https://www.r4photobiology.info/senpep-posts/led-arrays.html Tue, 09 Jul 2024 21:00:00 GMT Migration from Wordpress to Quarto Pedro J. Aphalo https://www.r4photobiology.info/senpep-posts/ The Plant Photobiology Notes. That was 29 years ago! It was written manually in a text editor and later using the HTML editor DreamWeaver. In 2009 I started using the Wordpress server of the University of Helsinki, my employer. I retired in 2024, so I moved this website to Quarto and to a new URL. As with my other sites, I will be selective, and transfer only posts that remain of some interest, and when needed I will update also the content. There are 115 posts to check and fewer to transfer. ]]> website news https://www.r4photobiology.info/senpep-posts/ Mon, 10 Jun 2024 21:00:00 GMT Fitted-model labels in Markdown Pedro J. Aphalo https://www.r4photobiology.info/galleries/plot-equations-markdown.html plotting data visualization ggpp ggpmisc ggtext ggplot2 https://www.r4photobiology.info/galleries/plot-equations-markdown.html Fri, 31 May 2024 21:00:00 GMT Pedro J. Aphalo https://www.r4photobiology.info/presentations/research-40-years.html slides from talk https://www.r4photobiology.info/presentations/research-40-years.html Mon, 27 May 2024 21:00:00 GMT Is this a polynomial? Pedro J. Aphalo https://www.r4photobiology.info/posts/is-this-a-polynomial.html lm() or rlm() would be silently accepted as input but only some formulations would result in valid equation labels added to plots. The statistics expect what to me feels like the “normal” way of writing a polynomial, agreeing with the expectation of polynom::polynomial() used internally. Although this is clearly described in the documentation, some users had different expectations. So, in spite of the examples in the documentation an issue was raised for a bug. Of course, the lack of a test to validate the argument to ensure the returned value is correct was an important bug, but not as the user who raised the issue thought, one affecting input that was deemed correct by design. To address this I added the previously missing test. ]]> R plotting ggpmisc https://www.r4photobiology.info/posts/is-this-a-polynomial.html Wed, 15 May 2024 21:00:00 GMT Learn R: As a Language 2ed Pedro J. Aphalo https://www.r4photobiology.info/posts/publications/learnr-book-ed-qmd.html
]]> website news https://www.r4photobiology.info/posts/publications/learnr-book-ed-qmd.html Mon, 29 Apr 2024 21:00:00 GMT