I’m on a weeklong break for winter vacation (Christmas and New Year’s Day). I’ll be back on Tuesday, 04 January 2022 with a new post. See you next year!
Archive for December, 2021
Happy Holidays!
December 28, 2021Best Photos of 2021
December 24, 2021The following gallery shows my “Best Photos of 2021.” 10 photos are presented in chronological order beginning in January 2021 and ending in December 2021.
01 January 2021
Buzz Lightyear: “To 2021 and beyond!”
Original blog post: To 2021 and beyond!
13 APR 2021 | Prince William County, VA | Selys’s Sundragon (male)
13 APR 2021 | Prince William County, VA
13 APR 2021 | Prince William County, VA | Uhler’s Sundragon (female)
05 JUN 2021 | Fairfax County, VA | Unicorn Clubtail (male)
17 JUN 2021 | PNC. Wm. County | Yellow-sided Skimmer (female)
17 JUN 2021 | PNC. Wm. County | Bar-winged Skimmer (mature male)
09 September 2021
It’s challenging to get all of the parts aligned for an image like this. In this case it’s close but not perfect. It would have been helpful to compose the shot with my camera tethered to a computer that features a larger screen than the one on the back of my camera.
All of that being said, the slight imperfections don’t diminish the visual impact of this image: Comet Darner (Anax longipes) exuviae are much larger than Common Green Darner (Anax junius) exuviae!
Relative size of exuviae from Anax junius versus Anax longipes.
Original blog post: Anax junius versus Anax longipes
04 October 2021
This is the only photo I’ve added to my Odonart© Portfolio recently. I love this beautiful specimen!
Comet Darner (Anax longipes) | exuvia (lateral)
Original blog post: Comet Darner exuvia: photo sketch pad
14 December 2021
Annotating images adds value, and I think it’s an under appreciated art form.
Original blog post: Determining final instar the Cham way
Copyright © 2021 Walter Sanford. All rights reserved.
New Life List additions in 2021
December 21, 2021The anticipation of the hunt and the thrill of discovery — the adrenalin rush from finding new species of odonates is ever more elusive as one gains experience and expertise. Accordingly, the number of additions to my Life List is fewer year after year.
Selys’s Sundragon (Helocordulia selysii)
A Selys’ Sundragon dragonfly (Helocordulia selysii) was spotted during a photowalk along a mid-size stream at an undisclosed location in Prince William County, Virginia USA.
This individual is a male with a malformed abdomen. Selys’s Sundragon is a new species for both my Life List of odonates and for Prince William County, VA.
13 APR 2021 | Prince William County, VA | Selys’s Sundragon (male)
Uhler’s Sundragon (Helocordulia uhleri) and Selys’s Sundragon are colocated at many sites — find one species and you should find the other. I’ve been on the lookout for Selys’s since Uhler’s was found several years ago near the site where this Selys’s was spotted.
Yellow-sided Skimmer (Libellula flavida)
Yellow-sided Skimmer dragonflies (Libellula flavida) were spotted around a small pond at an undisclosed location in Prince William County, Virginia USA.
The first individual is a female, as indicated by her terminal appendages.
17 JUN 2021 | PNC. Wm. County | Yellow-sided Skimmer (female)
The last individual is a male, as indicated by his blue coloration and terminal appendages.
17 JUN 2021 | PNC. Wm. County | Yellow-sided Skimmer (male)
Many species of dragonflies in the Family Libellulidae (Skimmers) are habitat generalists and relatively easy to find almost anywhere there is water. In contrast, Yellow-sided Skimmer is a habitat specialist that is challenging to find.
Tiger Spiketail (Cordulegaster erronea)
A Tiger Spiketail dragonfly (Cordulegaster erronea) was captured along a small stream at an undisclosed location in Prince William County, Virginia USA. The specimen was photographed and released unharmed.
05 AUG 2021 | Prince William County, VA | Tiger Spiketail (male)
This individual is a male, as indicated by his hamules, “indented” hind wings, and terminal appendages.
05 AUG 2021 | Prince William County, VA | Tiger Spiketail (male)
“Sight records are insufficient” is one of many “Walterisms.” In other words, I don’t add a species to my Life List until I have photographed it. And so it is with Tiger Spiketail. I have seen several Tiger Spiketail dragonflies during the past few years (at several locations) but had no photos to show for my efforts because they are fliers rather than perchers.
Copyright © 2021 Walter Sanford. All rights reserved.
Apple Sidecar
December 17, 2021Apple “Sidecar” is a free utility that enables you to use an iPad as a secondary display for your Mac.
Sidecar is only compatible with relatively newer devices such as my MacBook Air (M1, 2020) and iPad mini 6. [Note: Significant capability is added to my iPad mini by pairing the tablet with a Logitech “KEYS-TO-GO” wireless keyboard (compatible with both my iPad mini and MacBook Air) and Apple Pencil (2nd generation) or Logitech Pebble M355 Wireless Mouse.]
I tested Sidecar recently and I’m pleased to report it works as advertised. I’m just starting to think about how to utilize Sidecar. Any suggestions? If so, then please comment on this post.
Must-see TV
The show notes for the following video by Apple Support lists a link to a Web page entitled “Use an iPad as a secondary display for a Mac.” The first section is called “Get ready” and includes a sub-link to another section called “Sidecar system requirements” (located near the end of the same page). Also see the next section, “Additional requirements.”
The next video by Tech Gear Talk provides lots of useful guidance for making settings, how Sidecar works, as well as some practical applications.
The last video by Terry White answers the obvious question, “Can your iPad be used as a graphics tablet for use with mac OS applications such as Adobe Photoshop?” The answer, in a word, is “Yes!”
As you might have guessed I’m wondering whether Sidecar can be used to enhance my Photopea workflow. More later after I experiment.
Copyright © 2021 Walter Sanford. All rights reserved.
Determining final instar the Cham way
December 14, 2021Did you notice I added a new text label to the annotated image of an exuvia from a Comet Darner dragonfly (Anax longipes) featured in my last two blog posts? I added the label in order to make the connection between this image and related ideas discussed in two other relatively recent blog posts (See Related Resources, below).
Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back. “S4” stands for abdominal segment four.
Counting odonate abdominal segments can be challenging sometimes. A good strategy to avoid mis-numbering is to begin counting abdominal segments from S10 (located toward the posterior end of larvae (nymphs)/exuviae) and work toward the thorax.
Final instar, the Cham way
There is a simpler way to estimate final instar than calculating instar equivalent.
Larvae in the final stage can be recognized by the length of the wing buds which cover the fourth abdominal segment. Source Credit: Field Guide to the larvae and exuviae of British Dragonflies, by Steve Cham, p. 30.
Look at the preceding annotated image. Notice the tips of the wing pads reach the fourth abdominal segment (S4), indicating the dragonfly larva that emerged from this exuvia had reached final instar. And that leads to the other idea I mentioned at the outset of this blog post.
Every odonate exuvia is a cast skin of the larva at F-0, the final instar, before it emerges to become an adult.
Turns out that’s another nugget of gold paraphrased from Steve Cham’s beautiful little book.
Post Update
The beauty of the Cham way of determining final instar is it’s simplicity. That’s the upside. The downside is there’s no way to determine the actual instar when it isn’t F-0.
For example, the following composite image shows dorsal views of a Common Green Darner (Anax junius) nymph (larva) and exuvia. As expected, the exuvia is F-0 because its wing pads cover S4. On the other hand, the nymph is F-? because its wing pads only reach S2.
Image used with written permission from Freda van den Broek.
Photo Credit: Both specimens (shown above) were collected by Freda van den Broek. The nymph was collected on 06 April 2020 from the Milwaukee River in Ozaukee County, Wisconsin USA, photographed, and released unharmed. The exuvia was collected from Ozaukee County too.
Related Resources
- Proof of concept and Proof of concept, revisited
- How to estimate instar, revisited
- How to estimate instar
Copyright © 2021 Walter Sanford. All rights reserved.
Proof of concept, revisited
December 10, 2021In this blog post I’m going to show you how I used Photopea to annotate one of my photos. The workflow using Photopea is virtually identical to the way I annotate photos using Adobe Photoshop.
The original photo was edited using Apple Aperture (a discontinued photo editor) and Photoshop (for spot removal and sharpening). I could have attempted to edit the photo using Photopea but that wasn’t the point of my “Proof of concept” blog post.
Finished project
The first screen capture shows the finished project — I used it to reverse-engineer the steps that I took to create the annotated image and the settings I made along the way.
The “Layers” panel (located in the right sidebar) shows the finished project is compromised of seven layers, listed from bottom to top in the order they were created.
The “Background” layer is the photo itself. Go to File / Open… and navigate your computer to find a photo you would like to annotate.
View / Rulers
Before proceeding, it’s helpful to turn on “Rulers.” More about that later. In the Photopea menu bar, go to View and check Rulers.
Tech Tips: command-R (macOS) is a keyboard shortcut that can be used to toggle Rulers on/off.
The “View” menu also includes “Zoom In” and “Zoom Out” plus the associated keyboard shortcuts.
Press and hold the spacebar. Notice the arrow-shaped cursor turns into a hand that can be used to drag the canvas around the work space.
Post Update: View / Screen Mode > Fullscreen will scale up the Photopea window to fit the size of your computer screen. Fullscreen mode makes it much easier to work on fine details, especially when used in combination with the “Zoom Tool” and “Hand Tool”; the icon for both tools appears in the lower part of the left sidebar. Try it — you’ll like it! Uncheck “Fullscreen” in order to return to the desktop view. By the way, did you notice I added another guide line and Text layer for a follow-up blog post?
Text Tool settings: Title
The title is the first layer I added using the following selections: IBM Plex Sans (font type); SemiBold (font style); Size = 150 px; Color = Black; and “Aa” = Sharp.
Tech Tips: Text size is measured in pixels, not points. I’m not sure Photopea is calibrated correctly to convert points to pixels. Test it yourself using one of many online points-to-pixels calculators such as PT to PX Converter.
No matter, click the down arrow beside text “Size” and simply use the slider to select a text size that you like. You can also highlight the pixel size and type the exact number you prefer.
To begin adding text to your project, select the “Text Tool” (located in the left sidebar), click an insertion point on the photo and start typing. The default name for the new layer is “Text layer 1, 2, 3, etc.”
When you are finished, either delete the layer by clicking the “Cancel” button (X icon located near the right end of the Photopea menu bar) or save changes made to the layer by clicking the “Confirm” button (checkmark icon located to the right of the X) and the layer name changes so it is the same as the text you typed. In this case, I shortened the name of the layer to “Comet Darner dragonfly.”
With the layer selected, click on the “Move Tool” (left sidebar, at the top) and click-and-drag the text to reposition it exactly where you like.
Text Tool settings: Labels
Next I added a layer for “eye (1 of 2),” one of several labels for parts of the anatomy, using the following selections: IBM Plex Sans (font type); Regular (font style); Size = 100 px; Color = Black; and “Aa” = Sharp.
Tech Tips: The “Sharp” setting is used to avoid text with “jaggies,” that is text with saw tooth edges.
As an aid for aligning text, I created a blue guide line by clicking on the ruler along the top of the screen and dragging down to position the guide line on the photo. The guide line can be repositioned using the “Move Tool.”
Line Tool settings
The next layer I added is an arrow that points from the label to the anatomical part, in this case an eye. The settings I used for “Arrow 1” are shown in the following screen capture.
Tech Tips: Add a new vertical guide line for Arrow 1 by clicking on the ruler along the left side of the screen and dragging to the right to position the guide line on the photo. Right-click on the “Rectangle Tool” and select the “Line Tool.” I used shift-click-and-drag to draw a straight arrow that is aligned with the new blue guide line.
Add more layers
I followed the same steps described above to add a Text layer for “wing pads,” a new guide line for Arrow 2 and an arrow that points from the label to the anatomical part, and another Text layer for “prementum.”
Saving / Exporting
I saved the final image as a Photoshop document by selecting File / Save as PSD. The resulting PSD file can be reopened in Photopea in order to continue working on the project. Post Update: .psd files created by Photopea can be opened in Adobe Photoshop, although it is likely the font(s) you chose to use in Photopea are not available in Photoshop. Photoshop will prompt the user to resolve the problem.
I also saved the file as a PNG by selecting File / Export as.
What are the take-aways?
Open Photopea in a Web browser: www.photopea.com (For what it’s worth, I prefer “Google Chrome.”) Since Photopea is Web-based, it runs on desktop computers, laptop computers, tablets, and smart phones. Having said that, I think it would be challenging to annotate a photo with a tablet or phone unless those devices are used in combination with an external keyboard and mouse. Not impossible, but definitely challenging.
My dear friend Phil Wherry passed away too long ago. Phil was my tech guru for many years. I’m the type of person who suffers from “approach avoidance” — I like to know what will happen BEFORE I do something. One of the best bits of tech advice Phil shared with me is “Don’t be afraid to experiment and see what happens.” That’s exactly what I did when I used Photopea to annotate one of my photos and I encourage you to do likewise. Good luck!
Related Resources
Copyright © 2021 Walter Sanford. All rights reserved.
Proof of concept
December 7, 2021Can Photopea be used to annotate photographs? Yes!
Do the results look as good as photos of the same subject that were annotated using Adobe Photoshop? You be the judge.
Comet Darner (Anax longipes) | exuvia (lateral)
In my opinion the results are of comparable quality and that’s saying a lot considering this is my first attempt at using Photopea to annotate a photo.
As expected, the workflow flowed slowly since this was the first time I used many of the tools featured in Photopea.
I saved the final image as a Photoshop document by selecting File / Save as PSD. The resulting PSD file can be reopened in Photopea in order to continue working on the project. I also saved the file as a PNG by selecting File / Export as.
The Backstory
The preceding photo shows an exuvia from a Comet Darner dragonfly (Anax longipes) that was collected by Stanley Caveney on 19 July 2021 from a pond at MeadowWoods in West Elgin, Ontario, Canada. Sincere thanks to Stan for kindly sharing this beautiful specimen!
Related Resource: Learn Photopea
Copyright © 2021 Walter Sanford. All rights reserved.
How to estimate instar using Photopea
December 3, 2021In two recent blog posts (see Related Resources, below), I showed how Adobe Photoshop can be used to make measurements that enable you to estimate the instar of odonate larvae (nymphs).
The process works well, that is, as long as you have Photoshop. Does that mean you’re out of luck if you don’t? In a word, no.
“Photopea” is a free alternative to Adobe Photoshop. Photopea is a Web-based clone of Photoshop — Photopea doesn’t do everything Photoshop does but it can be used to make measurements on photos using a workflow similar to the one I described in detail in a blog post entitled “How to estimate instar.”
Practical example using Photopea
Open Photopea in a Web browser: www.photopea.com (For what it’s worth, I prefer “Google Chrome.”) Since Photopea is Web-based, it runs on desktop computers, laptop computers, tablets, and smart phones.
In order to make this tutorial as simple as possible I went to the Photopea menu bar, navigated to File / New… and created the default blank white canvas, shown below. Note: You should go to File / Open… and navigate to a photo of an odonate larva.
Use the Photopea “Ruler Tool” to measure the length (in pixels) of two line segments: HwL (Hind wing Length); and HW (Head Width). If you don’t know how to measure “HwL” and “HW” then please refer to “How to estimate instar” for detailed, step-by-step instructions.
Right-click on the Eyedropper Tool — located in the left sidebar of the main window, as shown below — and select the Ruler Tool.
Click and drag line segment HwL, such as the sample line shown below. Record the length of the line, in pixels. Click the “Clear” button (optional) and repeat the same process for line segment HW (not shown).
Do the math to calculate instar equivalent and voilà, the result is a number that can be used to estimate instar based upon Ken Tennessen’s average instar equivalents. Again, please refer to “How to estimate instar” for detailed, step-by-step instructions.
Related Resources
- Dragonfly Nymphs of North America: An Identification Guide, by Ken Tennessen. Section 2.5.1 Determining Instar, pp. 27-28.
- A Method for Determining Stadium Number of Late Stage Dragonfly Nymphs (Odonata: Anisoptera), by Kenneth Tennessen.
- How to estimate instar
- How to estimate instar, revisited
- Learn Photopea
Copyright © 2021 Walter Sanford. All rights reserved.
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