Archive for the ‘Satellite’ Category

Search status

Friday, February 16th, 2007

Since January 28, the San Francisco police, the Coast Guard and Jim’s friends and family have conducted an extensive search to find him and his sailboat, Tenacious, off the California coast. I want to summarize the status of that search here, so that the broad volunteer community that’s done so much knows where we stand.

The Coast Guard’s air and surface search covered 132,000 square miles in the days immediately following Jim’s disappearance. This search was thorough: Planes, boats and helicopters covered much of the region repeatedly. Radio broadcast alerts were made for a week, and all marinas and harbors were canvassed repeatedly. It found no trace of Tenacious or Jim.

During the Coast Guard search and in the days that followed it, Jim’s friends and family assembled satellite imagery, collected wind and current data and arranged for more air and surface searches over the ocean and coast from Oregon and into Mexico. We have walked stretches of coastline and have postered marinas with details on the missing boat. The story has drawn attention from around the world.

Based on our knowledge of the boat and weather conditions, we do not believe that Tenacious could have outsailed our search, whether it was under power, adrift, sailing under autopilot, or even sailing at best possible speed. We have covered an enormous area.

In the last several days, the Friends of Jim group has reviewed all the data with Coast Guard officials. The fact is that we have no evidence as to what has happened to Tenacious or to Jim Gray. Neither we nor the Coast Guard can come up with a surface search plan that is likely to find either Tenacious or Jim, given everything that has been done already.

Accordingly, the Friends of Jim group is suspending its active effort to find Tenacious that has been centered here at the blog. For both the Coast Guard and the Friends of Jim, “suspension” means that the active search has been discontinued due to exhausting all present leads and the lack of new information. Of course, should we or the Coast Guard receive any new information, we will investigate it.

Understandably, Jim’s family is determined to continue to seek answers, but they deserve to be able to pursue them privately. The family deeply appreciates everything the Coast Guard and Friends of Jim have done.

Jim’s wife Donna asked me to add this statement of thanks from her on behalf of the family:

On behalf of our entire family, I would like to thank every individual and organization who helped, and is continuing to help, in a long and difficult search. As the search takes on a new direction, I want you to know that your faith, hard work and boundless creativity sustain us during this unbearable time.

Jim is very lucky to have you as friends and colleagues, and we are very lucky and grateful to have your support.

Below, in the previous post to the blog, we have posted recent photos of Jim, photos of Tenacious at anchor and under sail, and an email address where you can send any information that could help us with our search. Coast Guard and San Francisco Police contact numbers are also listed.

  • The e-mail address is
  • The Coast Guard contact number is (415) 399-3547.
  • The San Francisco police department contact number is (415) 553-1071.

Thank you, one and all, for this amazing effort to find our Jim.

Contact information and photos

Friday, February 16th, 2007

Anyone with information about Tenacious or Jim Gray should contact:

  • The San Francisco Police Department at (415) 553-1071.
  • The US Coast Guard at (415) 399-3547.
  • Our search email address,

Jim was last seen on January 28, 2007. Here are several photographs of him and of his 40-foot C&C sailboat, Tenacious, sail number 31869.

Jim Gray

Jim Gray



RADARSAT Image Analysis

Sunday, February 11th, 2007

RADARSAT possible target

We have updated with a list of possible targets from the RADARSAT images taken January 31st and February 3rd.  RADARSAT images are 12.5 m per pixel, so the boat should be about 1 pixel. Maybe not the best images, but we thought it was worth a try.

Maria Nieto-Santisteban & Jeff Valenti

Sunday afternoon update.

Sunday, February 11th, 2007

The storm that’s kept us on the ground for the last several days finally passed through overnight, so we were able to put two planes in the air today.

Those flights were aimed at specific search areas, based on results from our image processing and the work of our ocean surface drift modelling team. We had found two possible sightings of Tenacious in the imagery, and went out to look for it.

The first possible sighting was off the coast of Monterey, California. This image was captured by a NASA ER-2 overflight. The target was found by our image analysis team. We sent a flight out this morning that flew a search pattern over the area into which that boat would have drifted.

The second possible sighting was out past the Farallon islands, Jim’s intended destination on Sunday two weeks ago. This target was spotted by the volunteers working on the Amazon Mechanical Turk search, and was vetted by image processing experts who confirmed that it was the right size and shape to be Jim’s boat. As for the Monterey target, we put a plane in the air and flew a search pattern over the area into which we would have expected the boat to drift since the image was captured.

Neither of our flights found Tenacious. It was an excellent day for spotting, and we were able to see other craft and even wildlife — large submerged whales and orcas or dolphins at the surface.

We’re confident that the imagery shows sailboats, and that those boats are similar to Tenacious in size and shape. We flew thorough and careful searches. It’s highly likely that these were ordinary boats on the water, and in no distress. They weren’t Tenacious.

It’s good to see the results of our image processing and drift modelling turn up targets for our flight team. We still have imagery in the pipeline, and will put planes in the air as our analysis turns up new targets. Today’s results are disappointing, of course, but the search is still underway.

Thanks to those of you who got the science done, who arranged for the search flights, and who piloted or spotted on today’s flights.

Finding good examples for multispectral search

Sunday, February 11th, 2007


In order to test the multispectral search idea, I was wondering if some of you could help out. In order to have the instrument people figure out if there is even a chance of detecting a boat of the size of Tenacious I am wondering if somebody could help in locating some good examples featuring all the conditions listed below:

– Location of a known boat at a known time and GPS coordinates (sailing races that have been featured on GE or Google Maps, Maud Fontenoy recent trip, others….)
– Said location is within the coverage of either Landsat 5/7 or Envisat ( check , <– Internet Explorer only)

– Said Landsat5/7 or Envisat coverage has no cloud on the location of said boat.

As one can see the cloud coverage is pretty important:

Other possible imagery: Multispectral, Hyperspectral, Astronauts acquired

Friday, February 9th, 2007


This is a request for help to the remote sensing community and this is a long shot. I have been talking to some people over the past week about using some lower spatial resolution imagery with higher spectral resolution to see if we could somehow find Jim’s boat. While hyperspectral imagery seems available for a restricted set of conditions (too small of a swath for EO-1), there is multispectral imagery available with resolution between 30 meters to 260 meters.

* 30 meter resolution: In the EROS database of the USGS, there are multispectral views of the scene of interest at about the time that is interesting to our current search. While the resolution is not great (30 m Landsat 7 with ETM+), it seems one can still see boats, I summarized this finding here:

I would be expecting some data fusion process to happen eventually between the current set (ER-2, Radarsat, DG/Ikonos,…) and this new set. The other interesting side of this story would be to increase the search area to the whole coast of California.

However, I am not a remote sensing person, hence I do not have access to EROS imagery nor do I have access to processing capabilities at this time. Can somebody in the audience help ?

* The 260 meter resolution can be found on Envisat, a new european satellite:

and I found nine shots that could help our effort. The resolution is 260 meters but the resolution (S/N) is pretty high.

Again, does anybody know how to get a hold of this imagery for this effort fast, and can somebody process it ?

Finally, there is another possibility for taking a picture over the pacific ocean with a pixel resolution of about 30 meters per pixel: Astronauts Acquired Photographs taken from the International Space Station.

While we can get high resolution shots from Digital Globe, it may be worthwhile to have a much lower resolution but a larger field of view for certain areas especially if there is only one foreign object to detect. I am not quite sure about how to make a request for this type of imagery though.

Regarding the Green Dye near SD

Tuesday, February 6th, 2007

From the Coast Guard:

Good afternoon, Mr. Hellerstein,

I researched information regarding the green dye. On February 4, Sector San Diego responded to a report from aircraft of green dye which plots close to the possible lat and long given in the internet posting. They confirmed green dye 12 nautical miles offshore from Mission Bay. They did not see any debris, persons, vessels, or signs of capsized/sunken vessels in the area and suspended their search. It is important to note that Avalon Harbor places green dye in the ballast tanks of commercial vessels when they anchor in Avalon Bay. When these vessels depart for sea and pump their ballast tanks, it could be mistaken as a distress sign. I hope this helps you in your efforts.

LTJG Nephtwim Rosario
Sector Duty Officer
Sector San Francisco

Some Results from Analysis of ER-2 Data

Monday, February 5th, 2007


here there is a sample of some interesting objects we found in ER-2 data doing semi automatic detection

Candidate_Name       ,Filename    ,Date      ,UTC     , Longitude,Latitude,   X,   Y, Pk, N59438221_121552_35980,59438221.tif,2007-02-02,18:17:34,-121.55193,35.98013,2114,3125, 97, 659438221_121543_35974,59438221.tif,2007-02-02,18:17:34,-121.54253,35.97372,2435,2568, 97, 959438222_121580_35985,59438222.tif,2007-02-02,18:18:04,-121.58027,35.98466,1606,1497,193, 8


Possible candidates from ER-2 

The whole sample in


It would be great if we could collect coordinates in a common way and do cross-matches between images from different data sources or data analysis.


Jeff Valenti and Maria Nieto-Santisteban

confirmation of old Tenacious aerial photos

Sunday, February 4th, 2007

The post below is now obsolete, superceded by the updates you can find in this post from Wolfgang

There has been some question over email as to the photos of the docked Tenacious being accurate. Donna adds this information:

It is the right boat. One marker is how the boat to the starboard side of it looks. Even from the arial you can see the big, clunky boat cover on it.

I can also go down there early tomorrow (after the detective leaves) with the picture if you want any further confirmation and literally eyeball it. Donna

and this:

We changed slips sometime last year to move into this slip. Previously, we had been in the slip to the portside, which made getting in trickier, despite the fat size of our boat, as we could blow down on the starboard boat (that is, where our boat is now located) in heavy winds. So yes, the finger walkway to Tenacious in our current slip, and in the photo, is on the starboard side.

Leading to the question of whether the photo people have been using is before or after the move. Tom Barclay provided more pictures with timestamps:

The ortho view was flown in 2006. I’ll have to get you the exact date later.

The “Bird’s Eye” view was flown in 2005. We may have picked up a drop last year (2006), but I don’t believe so. Later today, I crawl into the engine room and validate the dates

The TerraServer-USA.Com view was flown in February 2004 (the date is on the web page)

Sunday, February 4th, 2007

From my own eyeball experience and for what I’m reading, it seems we are having trouble identifying whether or not what we see is actually a boat, but if the “whatever” we see looks the same two or three times, then it is likely to be something other than noise.

Is there any possibility of taking more than one image separated by some time to identify the boat as a moving object?  Or similarly, do we have images of the same area which have been taken in different times? Under good visibility conditions, while the ocean would remain pretty much the same, the boat (same shape) would show up.

I don’t know what would be the right time period, obviously depends on the boat’s speed and the image resolution.  In any case, the first thing to know is whether or not we have or may have the data. Does anybody know?

We could take good profit of multiple frames in either the manual or machine search.

Maria Nieto-Santisteban