RadarScope app

RadarScope, one of my favorite apps for Apple iOS devices, is a full-featured app that provides access to nearly the entire suite of Doppler weather radar products generated by the National Weather Service.

As a wildlife photographer I use RadarScope to make go/no-go decisions for photowalking outings. And when I’m already in the field, I use the app to decide whether it’s time to seek shelter from pop-up thunderstorms.

As a weather enthusiast, RadarScope enables me to track the approach and passing of weather systems such as the line of strong thunderstorms that affected the Washington, D.C. metropolitan region on Friday, 27 May 2022.

Composite Reflectivity

The first image shows “Composite Reflectivity.” This is the same type of weather radar imagery that has been used by TV weathercasters for years. In a nutshell, composite reflectivity shows precipitation intensity within range of a weather radar site, in this case KWLX — the NWS Forecast Office located in Sterling, Virginia.

27 MAY 2022 | 10:29 AM EDT | KWLX Sterling

Notice the line of heavy precipitation, indicated by a narrow band of red radar echoes, just to the west of my location in suburban Washington, D.C. (see blue reticle at the center of the screen). Forecast storm tracks (see incremented white lines) indicate individual storm cells are moving generally from southwest to northeast.

To view storm tracks in RadarScope, tap the settings icon in the lower right of the screen, then choose Layers and turn on the Storm Tracks option. The estimated times of arrival can be seen by touching anywhere along the track. Source Credit: RadarScope: How are Storm Tracks Computed? [Editor’s Note: In my experience, this feature works only when I tap the white circle at the origin of each storm track.]

Storm Relative Velocity

“Storm Relative Velocity” shows the wind velocity in a storm minus the forward motion of the storm. Greens show motion toward the weather radar site; reds show motion away from the radar (like car tail lights).

27 MAY 2022 | 11:21 AM EDT | KWLX Sterling

Look closely at the full-size version of the preceding image. Notice the yellow polygon located between Beaverdam and Fredericksburg, Virginia that delineates the boundaries of a severe thunderstorm warning area.

There is a red polygon (located inside the yellow polygon) that represents a tornado warning area. Within the boundaries of the red polygon, notice the juxtaposition of greens and reds — a good indicator of counterclockwise rotation in a storm cell. As it turns out, there were several official reports of a tornado on 27 May 2022 in the same location as indicated by the NWS Doppler weather radar.

It’s important to note that the orientation of side-by-side greens and reds typical of rotating thunderstorm cells varies depending upon the location of the storm cell relative to the weather radar site. In the example shown above the greens are on the right and the reds are on the left because the warning area is located to the southwest of KWLX. In contrast, if the warning area were located to the northeast of the radar site, then the reds would be on the right and the greens on the left.

Related Resources

The following resources from the National Weather Service provide excellent background information about Doppler weather radar.

• How radar works
• Composite Reflectivity
• Storm Relative Velocity

RadarScope features good in-app documentation, as evidenced by the following screen captures.

RadarScope | Help

RadarScope | User’s Guide

RadarScope | User’s Guide – Velocity Products

The same resources (and more) are available online.

• User’s Guide
• Information Articles
• RadarScope Blog

Copyright © 2022 Walter Sanford. All rights reserved.

 

GoPro: “Quik for Desktop”

GoPro legacy software “Quik for Desktop” (Ver. 2.7.0) can be used to add “Stickers” to video shot with a GoPro HERO5, 6, and 7, but doesn’t work with GoPro HERO8, 9, and 10. “Can be,” that is assuming the feature works with your camera/video. Huh? Please continue reading.

“Quik for Desktop”

My former colleague Kyle Margenau sent a video clip to me that he shot using his GoPro HERO5 Black action camera.

GoPro “Quik for Desktop” | Media

In order to edit a video, double-click on its icon in the Media library.

Editor’s Note: DO NOT click on “Open in Create Mode,” shown along the blue bar near the top of the screen — otherwise “you’re entering a world of pain!” “Create Mode” seems to be GoPro’s quick-and-dirty process for creating simple videos with added music for the purpose of sharing on social media. I tested the process so you don’t have to be frustrated — “Create Mode” was an epic fail!

There are four buttons for editing video, located along the lower-middle of the window. Shown from left-to-right, the four icons are “Create a Clip,” “Rotate 90°,” “Grab a Photo,” and “Adjust Gauges.”

GoPro “Quik for Desktop” | “Adjust Gauges” button

When I clicked the “Adjust Gauges” button (shown above, highlighted by a red square), the following error message appeared on-screen.

GoPro “Quik for Desktop” | No GPS Data

There are/were six “Stickers” available in “Quik for Desktop,” and they are somewhat different from the seven “Stickers” available in the “Quik” app (Ver. 10.15). Using “Quik for Desktop,” you can add as many stickers as you like; using the “Quik” app, you can add four stickers.

• GoPro Logo
• Info Cluster
• Speed Tracker
• GPS Path ← line with no context
• Speedometer ← better than the version in “Quik” app
• G-Force

I think it would be nice to include the exact latitude and longitude of the camera in the “Info Cluster.”

“Quik” app

The following JPG frame grab (2 MP) was saved from the “GoPro Quik” app (Ver. 10.15) running on my Apple iPad mini 6. Kyle’s vehicle is heading southeast at 17 mph.

Notice I juxtaposed the “Path” gauge (upper-left) with the “Terrain” gauge (lower-left) in order to underscore a point that I made in my last blog post — a line without any context/frame of reference is pointless.

GoPro “Quik” app.

As you can see by the telemetry “Stickers” shown in the preceding frame grab, Kyle’s video does in fact include GPS data. It’s worth noting the frame grab (shown above) does include EXIF but does not include GPS info for latitude, longitude, and elevation. C’mon GoPro — frame grabs from video could, and should include GPS info!

If you can determine the exact time of each video frame, you can use the exiftool -geotag and -geosync options to read the GPX file and geotag the extracted frames. Source Credit: ExifTool Forum.

I have NO IDEA why the “Adjust Gauges” feature in “Quik for Desktop” doesn’t work. I tested “Quik for Desktop” running on an older Apple iMac desktop computer (Intel) as well as a newer Apple MacBook Air (M1) — the “Adjust Gauges” feature didn’t work on either device.

I have watched several tutorial videos on YouTube that show the feature does work, or at least it did at one time.

Please contact me if you have any suggestions for troubleshooting this problem. Thanks!

Copyright © 2022 Walter Sanford. All rights reserved.

 

GoPro: How to add “Stickers”

Every GoPro action camera since the GoPro HERO5 Black features a built-in global positioning system (GPS) receiver; my GoPro HERO4 Black does not.

Assuming you own a GPS-capable GoPro camera, there is another case for using either “Quik for Desktop” or the “GoPro Quik” app to edit video: adding overlays to video, including stickers and telemetry gauges.

GoPro legacy software “Quik for Desktop” can be used to add “Stickers” to video shot with a GoPro HERO5, 6, and 7, but doesn’t work with GoPro HERO8, 9, and 10.

The “GoPro Quik” app can be used to add “Stickers” to video shot with HERO8, 9, and 10 cameras; it’s also backward-compatible with HERO5, 6, and 7.

It’s worth noting that the “GoPro Quik” app can be used to edit a single video clip for free, with some limitations. For details see GoPro Quik: Free Vs. Subscription Features. See also GoPro Quik App- All Your Questions Answered by Jordan Hetrick (12:33).

Add “Stickers”

My good friend and former colleague Kyle Margenau sent a video clip to me that he shot using his GoPro HERO8 Black. First the video clip was saved to “Photos” on my iPad mini 6, then it was added to “Media” in the “GoPro Quik” app.

Tap the “Media” icon (shown below, highlighted by a red square) to see “All Media” saved to the “GoPro Quik” app. Kyle’s video appears at the top of the list on the page, last saved on Friday, May 13 [2022].

GoPro “Quik” app | All Media

As you can see, I already edited the video to add several “Stickers.” Tap the pencil icon (shown below, highlighted by a red square) to edit the video.

GoPro “Quik” app.

Tap the “Stickers” button (shown below, highlighted by a red square).

GoPro “Quik” app.

Up to four stickers can be displayed on the video, one in each corner.

There are currently 7 stickers available in the app:

1. GoPro Logo
2. Speedometer ← speed plus compass heading
3. Terrain ← unavailable in “Quik for Desktop”
4. Path ← line with no context
5. Speed Chart
6. Altitude
7. G-Force

Source Credit: GoPro Quik: How To View Stickers.

In the following screenshot notice that blue tick marks indicate the “Stickers” that have been added to the movie.

GoPro “Quik” app | Stickers

Add more “Stickers” by tapping one of the icons (shown above, highlighted by a red rectangle). By default, the new sticker will be shown in the upper-left corner of the movie. Tap the same icon again in order to reposition the sticker to the upper-right corner. Tap the same icon again to move the sticker to the lower-right corner; tap it a fourth time to move it to the lower-left corner. Tap the same sticker icon five times in order to delete it from the movie.

Tap the ✔️ icon (lower-right corner) when you are finished (shown above, highlighted by a red square).

Save Media

Wait, you need to do one more thing. Tap the “Save” icon (shown below, highlighted by a red square) in the upper-right corner in order to save your edited video.

GoPro “Quik” app.

The following screenshot shows where the video can be saved. There are three (3) options; I recommend “Save to Photos” (shown below, highlighted by a red rectangle).

GoPro “Quik” app.

Grab Photo

Play the annotated video clip and when you see a frame you’d like to grab, pause playback and tap the “Extract Photo Icon” located along the bottom of the screen (shown below, highlighted by a red square). For more detailed directions, see GoPro: How to “Grab Photo” from Video.

GoPro “Quik” app.

You have the option to scrub through the video frame-by-frame (by using the left and right arrows) until you find a frame that you’d like to save as a photo. Tap the blue “Save Frame” button located in the upper-right corner of the “Grab Photo” screen (shown below, highlighted by a red rectangle). Then choose the location where you would like to save the frame grab: Save to App; Save to Photos; Share Media.

GoPro “Quik” app | Grab Photo

The following video frame grab (4 MP) was saved from the “GoPro-Quik” app. Kyle’s vehicle is heading southeast at 22 mph.

GoPro “Quik” app.

The last screenshot was taken from the video using the Apple “Photos” app. Notice the black bars along the top and bottom of the screen. Kyle’s vehicle is heading southeast at 12 mph.

Apple “Photos” app.

What are the take-aways?

Could the GoPro Logo “Sticker” be any bigger? It’s ridiculously big! It shouldn’t be too difficult to update the “GoPro Quik” app to enable the user to resize/reposition “Stickers,” similar to the way it works in “Quik for Desktop.”

In my opinion, the Speedometer and Terrain “Stickers” are two of the more useful telemetry gauges.

It would be nice to add numbers to the tick marks on the Speedometer. In this case, the Speedometer is marked in increments of 10 mph, but the increment varies depending upon what is shown in your movie. Also, it would be nice to show an exact number for compass direction, from 0-360°.

The Terrain “Sticker” shows the path of the camera superimposed on a map. It would be nice to have the option to select the map type, such as street, terrain, or satellite. In contrast, the Path “Sticker” is simply a line that traces, well, the path of your camera. In my opinion, a line without any context/frame of reference is pointless, but hey, use the Path “Sticker” if you like.

Related Resources

• How To Turn On GPS With GoPro Cameras, by GoPro
• GoPro Quik: How To View Stickers, by GoPro
• GoPro: How to “Grab Photo” from Video
• Kyle Margenau YouTube channel
• Add GPS Telemetry (Speed, Altitude, etc.) to your GoPro Footage, by Ed Ricker (11:47)

Copyright © 2022 Walter Sanford. All rights reserved.

GoPro: How to “Grab Photo” from Video

When you use either the “GoPro app” or “GoPro Quik” app to remotely control your camera, you can save still photos from a video clip. For example, here’s how it works using “GoPro Quik” on my Apple iPad mini 6.

The first screen capture shows the “splash page” for GoPro Quik, running on my iPad mini 6. Tap the camera icon labeled “GoPro” located in the lower-right corner of the screen. The button works, despite the fact that it’s grayed out.

GoPro “Quik” app splash screen.

Next, tap the button labeled “Control Your GoPro” on the “Cameras” page.

“Cameras” screen, GoPro “Quik” app.

Tap the “Media Icon” located in the lower-right corner of the Live View screen (shown below, highlighted by a red square) in order to see photos and videos that you have recorded using your GoPro camera.

Live View, GoPro “Quik” app.

When you play a video clip shot with the camera and see a frame you’d like to grab, pause playback and tap the “Extract Photo Icon” located in the lower-middle of the screen (shown below, highlighted by a red square).

Video playback, GoPro “Quik” app.

You have the option to scrub through the video frame-by-frame (by using the left and right arrows) until you find a frame that you’d like to save as a photo. Then tap the blue “Save Frame” button located in the upper-right corner of the “Grab Photo” screen.

“Grab Photo” screen, GoPro “Quik” app.

Choose the location where you would like to save the frame grab.

Select “Save to …” location, GoPro “Quik” app.

The frame grab is saved as an 8 MB JPG file, smaller than the 12 MB JPGs created when the camera is set for “Photo Mode.”

The file can be adjusted using your photo editor of choice, but there’s a limit to what you can do during post-processing of JPGs so it’s always a good idea to “get it right” in-camera.

Related Resources

• Export an image from iMovie on Mac – This process works using iMovie for Mac OS.
• Grab a Single Frame from a Video in QuickTime X
• How to Capture a Video Frame with VLC

Copyright © 2022 Walter Sanford. All rights reserved.

GoPro two-for

This blog post is a GoPro two-for. First I will prove that there are only two user-selectable settings that can be made using the GoPro HERO4 Black action camera set for Video Mode / “Time Lapse Video” submode. Second I will demonstrate two settings that you should make under Setup Mode in order to use your GoPro camera as a Webcam.

I used a relatively inexpensive MavisLink Video Capture Card to connect my GoPro HERO4 Black to an Apple MacBook Air. Open Broadcaster Software (OBS Studio) was used to record two video clips showing the small LED screen on the front of the HERO4 Black.

Video Mode / “Time Lapse Video” submode

The following short video (0:34) shows all of the settings that can be made in Video Mode / “Time Lapse Video” submode. First I cycled through all of the submodes under Video Mode. Next I cycled through all of the setting options under “Interval.” Finally, I cycled through the settings under “Resolution.”

Like I said in my last blog post, there are two user-selectable settings in the “Time Lapse Video” submode: Interval; and Resolution.

At the end of the video clip, the screen goes black (there was a lens cap on my camera) except for information displayed in white text at the top and bottom of the LCD screen. GoPro calls that “On Screen Display”; some people refer to it as a “heads up display.” More about that in the next section.

“Clean HDMI”

“Clean HDMI” output and continuous power are considered to be essential if a camera is suitable for repurposing as a Webcam. Two settings are recommended in “Setup Mode” in order to use the HERO4 Black as a Webcam.

Use the Power/Mode Button (front of camera) to scroll down through the menu items until you reach “On Screen Display.” This setting can be toggled ON or OFF; set it to “OFF” by pressing the Shutter/Select Button (top of camera). The next menu item is “Auto Off”; set it to “Never” so the camera won’t power-off automatically. Finally, press the Settings/Tag Button (side) to exit the Setup menu.

Notice the “On Screen Display” is gone when the screen goes black at the end of the video. Ah, “clean HDMI!”

Thanks to YouTuber “Tech Explores NYC” for showing me how to setup my GoPro HERO4 Black for use as a Webcam!

Related Resources

• MavisLink Video Capture Card
• Open Broadcaster Software (OBS Studio)

Copyright © 2022 Walter Sanford. All rights reserved.

GoPro time lapse submodes

The GoPro HERO4 Black action camera features three ways to either create (in-camera) a simple, time lapse movie in MP4 format or shoot a time series of photos (JPGs) that can be used to create a time lapse movie during post-processing.

Video Mode

“Time Lapse Video” submode

“Time Lapse Video” is one of several submodes under “Video Mode,” as shown below. It’s the simplest way to create a time lapse movie using the HERO4 Black.

GoPro “Quik” app.

There are two user-selectable settings in the “Time Lapse Video” submode (shown below, highlighted by a green rectangle): Interval; and Resolution. I selected an interval of 1 second and a resolution of 4K at 30 frames per sec (fps).

Settings, “GoPro app” (v7.1)

The preceding screen capture from the “GoPro app” (v7.1) seems to suggest there are many more user-selectable settings in “Time Lapse Video” submode; there aren’t. Call it an artifact of lazy app coding. I call it confusing! For reference, see p. 20 in the GoPro HERO4 Black User Manual (shown below).

GoPro HERO4 Black | User Manual

When the GoPro HERO4 Black is set for “Time Lapse Video” submode, the camera records MP4 videos with a 16:9 aspect ratio (3,840 x 2,160 pixels). File size varies depending upon the duration of the video clips.

Try it. I think you’ll like it. Make the same settings that I used and start recording. Just be sure to record long enough to create a “Goldilocks movie,” that is one that isn’t too short and isn’t too long but is just right.

Standard video playback is typically 30 frames per sec in the USA. If you record every second for 30 seconds, your final movie will be 1 second long! Plan to record for at least 10 to 15 minutes.

Based upon my settings the camera created two video clips: the first is 17 seconds in duration; the last is 28 seconds. That’s a total of 45 seconds long, before I trimmed the video clips using Apple iMovie. In order to smooth the playback and lengthen the final movie a little, I used iMovie to adjust the playback speed to 25% of normal.

Multi-Shot Mode

“Time Lapse” and “Night Lapse Photo” submodes enable automated recording of photos that can be used to create a time lapse movie during post-processing.

GoPro HERO4 Black | User Manual

The two submodes are similar, with one key difference: both Interval and Shutter Speed are user-selectable in “Night Lapse Photo” submode; only Interval is user-selectable in “Time Lapse” submode. A wide range of other user-selectable settings are available in both submodes, including “Protune.”

GoPro HERO4 Black | User Manual

“Time Lapse” submode

Untested, so far. Please stay tuned.

GoPro “Quik” app.

“Night Lapse Photo” submode

GoPro “Quik” app.

I tested “Night Lapse Photo” submode on the same day I created the time lapse movie featured in my last blog post. In case you’re wondering why I used “Night Lapse Photo” to record a scene during the day, I did so based upon the camera settings recommended by a well-known time lapse photographer/videographer.

27 APR 2022 | 3:47 pm | DCIM100GOPROG0020165

168 JPG photos were recorded during a 14 minute time period starting at 3:47 pm and stopping at 4:01 pm.

27 APR 2022 | 4:01 pm | DCIM100GOPROG0020332

As you can see in the two sample photos (shown above), the sky was overexposed in all of the photos that were recorded. The Interval was set for five (5) seconds and set the Shutter Speed was set for Auto. Those settings might work for Mr. X but they didn’t work for me!

The GoPro HERO4 Black records JPG photos with a 4:3 aspect ratio (4,000 x 3,000 pixels). Each photo file is approximately 2.2 MB in size.

The GoPro HERO4 Black features a fixed lens with an aperture of f/2.8.

The 35mm equivalent focal length of the lens is 15mm. That’s a fairly wide angle lens, so it’s no wonder the preceding photos show some “fish eye” distortion.

Notice the Shutter Speed was 1/120 second. Although 1/120 s is a relatively slow shutter speed, it’s fast enough that it might not explain why my photos are overexposed.

The scene I recorded was relatively high contrast — it was dark in the parking garage and the white clouds in the sky were bright. It’s possible the “Center Weighted Average” Metering Mode was unable to expose the entire image properly.

I didn’t know that Photo Mode / Night Photo submode and Multi-Shot Mode / Night Lapse Photo submode are virtually identical. Next time I experiment with “Night Lapse Photo” I will shoot some test shots using “Night Photo” to be sure the exposure is set correctly before starting “Night Lapse Photo.”

That being said, I think my next experiment will test “Time Lapse” submode.

Copyright © 2022 Walter Sanford. All rights reserved.