Photo Essays

April 18, 2009: Chasing birds by day and alligators by night with Ben

Ben has an airboat. I like adventures. Ben is very accommodating when it comes to photo shoots with this old man. I was all prepared with my GPS, camera and camera gps. The good news is we had a great time. The bad news is that the GPS failed to capture the tracks of our adventure. Hmm I thought, maybe I can extract the GPS coordinates from the images and reconstruct the track from the camera data. It worked as you can see below.

Here is where we went

<a href="gps/apr_18_2009_panasoffkee.html">Click here for the map</a>

and here is how I recovered from my loss of GPS data

using exiftool, I extracted the EXIF data from one of the Nikon jpg images: exiftool dsc_0276.jpg and the tail of the EXIF file segment containing the GPS data is displayed as:

GPS Altitude                    : 17 m Above Sea Level
GPS Date/Time                   : 2009:04:18 21:01:53
GPS Latitude                    : 28 deg 48' 22.42" N
GPS Longitude                   : 82 deg 8' 14.06" W
GPS Position                    : 28 deg 48' 22.42" N, 82 deg 8' 14.06" W
Image Size                      : 4288x2848
Lens ID                         : AF-S DX VR Zoom-Nikkor 18-200mm f/3.5-5.6G IF-ED
Lens                            : 18-200mm f/3.5-5.6 G VR
Shutter Speed                   : 1/1000
Create Date                     : 2009:04:19 05:01:55.00
Circle Of Confusion             : 0.020 mm
Depth Of Field                  : 0.02 m (1.49 - 1.51)
Field Of View                   : 6.0 deg (0.16 m)
Focal Length                    : 200.0 mm (35 mm equivalent: 300.0 mm)
Hyperfocal Distance             : 199.69 m
Light Value                     : 15.6

Using the EXIF field labels, I was able to write an awk script to grab the Create date, latitude and longitude and write as a single record using commas to separate the fields:

BEGIN {FS=":";}

/GPS Latitude/	{lat=$2;}
/GPS Longitude/	{long=$2;}
/GPS Position/	{position=$2;}
/Create Date/	{month=$3; day=$4; hour=$5; min=$6; sec=$7 }

END 		{printf("%s:%s:%s:%s%s,%s,%s\n", month,day,hour,min,sec,lat,long);
		$lat="";\
		$long="";\
		$date="";\
		}

Finally, I pulled all the pieces together with a shell script to extract the GPS data from every jpg image starting with dsc_:
```
for i in dsc_*
do
exiftool $i | awk -f get_gps.awk
done
```

Then I ran ./make_track.sh >apr_18_2009_panasoffkee.csv to get the data and save it in a file using csv as the file type - which appeared as

date,latitude,longitude
04:19 04:35:20.00, 28 deg 48' 22.12" N, 82 deg 8' 11.54" W
04:19 04:35:56.00, 28 deg 48' 21.98" N, 82 deg 8' 11.20" W
04:19 04:35:58.00, 28 deg 48' 22.00" N, 82 deg 8' 11.20" W
04:19 04:37:07.00, 28 deg 48' 21.95" N, 82 deg 8' 10.43" W
04:19 04:37:11.00, 28 deg 48' 21.95" N, 82 deg 8' 10.43" W

Then uploaded the file to GPS Visualizer map option.
Saved the html for the map as apr_18_2009_panasoffkee.html
Added my Google Maps key in the api field
And it worked

Chasing birds with Ben and Steve (Ben's father-in-law)

apr 18 0187 2 birds

This bird provided an action shot - sort of a bit of wc action and then (right) pretended that nothing happened. Note the orientation of the tail feathers on the left and right

apr 18 0211 bird wc apr 18 0212 bird after wc

A blue heron

apr 18 0255 blue heron

Evening - This almost looks like a painting and I don't know what I did to provide this appearance

apr 18 0276 evening

Three trees

apr 18 0352 3 trees

A yellow lotus blossom

apr 18 0407 yellow lotus

From the top

apr 18 0413 yellow lotus

A blue dragonfly on a green lily pad

apr 18 0418 blue on green

A wider view

apr 18 0422 blue on green

Ben's airboat

apr 18 0454 bens airboat

A white bird flying - nice light

apr 18 0485 white bird flying

The river

apr 18 0526 river

Two birds

apr 18 0532 2 birds

A blue heron

apr 18 0555 blue heron

Steve and the two kids - Ben Jr and Hunter

apr 18 0677 steve

A very interesting insect - similar to a crane fly - but I don't know.

apr 18 0706 long leg insect

Shades of green

apr 18 0711 shades green

The beauty of flight

apr 18 0721 flight

Steve moving away

apr 18 0726 steve ben hunter

A bit of science - the airfoil shape of the blue heron's wing

apr 18 0730 airfoil

The river

apr 18 0739 river

A white something

apr 18 0806 white bird

Quiet river

apr 18 0832 river

Flying in formation

apr 18 0856 quad flight

A quartet

apr 18 0872 flight

Flying away - First time I've captured the tip feathers

apr 18 0885 trio fly away

An Osprey, Pandion haliaetus

apr 18 0895 ospry

A group of birds just gossiping

apr 18 0901 resting

A bit more small talk

apr 18 0903 birds resting

Until they heard Ben's boat and off they go<,p> apr 18 0905 takeoff

The elegance of flight - score a perfect 10 for straight legs

apr 18 0908 white bird

Now its about 9pm and we are launching the boat for chasing alligators. This is a 30 sec exposure - with noise reduction turned on

apr 18 0914 launch

The face of a small alligator

apr 18 0984 gator face

The teeth of a small alligator

apr 18 0990 gator teeth

Ben holding the alligator

apr 18 0993 ben

The iris of its eye

apr 18 1001 gator iris

Another alligator on the water's edge

apr 18 1002 little gator

Different position. By the way - Ben has a very bright spotlight and I"m using a flash

apr 18 1004 little gator

This was an interesting photo - the red reflection of the alligator's eye in the center of the photo - just Ben's light - about 50 years away

apr 18 1011 gator eyes

Hiding

apr 18 1020 gator water eye

A large (8') alligator in the water

apr 18 1033 night gator

Swimming away from us

apr 18 1035 big gator

Under water

apr 18 1042 underwater gator

Another slit eye

apr 18 1054 big gator

This work is licensed under a Creative Commons License.

C. Frank Starmer

Photo Adventures with Curiosity and Learning