I had a recent project to establish LiDAR control for all of Puerto Rico and the US Virgin Islands. My part of the project was to do the three US Virgin Islands, as well as the Puerto Rican islands of Culebra, Vieques, and Mona. And then do some work on the main island to supplement what my employee was doing there. Total of 241 points, 200 on the main island.
Day 1: landed in St Thomas, setup a base, surveyed on St Thomas using RTK over cell.
Day 2: ferry to St John, used the same base on St Thomas, surveyed points on St John, then returned to St Thomas and flew to St Croix, setup a base there, and surveyed points. Had to do static on one point due to no cell.
Day 3: completed survey on St Croix, flew to San Juan
Day 4: flew to Culebra, surveyed on Culebra from a temporary base. Here is the approach into Culebra, which the pilot warned us would be a bit steep.
https://youtube.com/shorts/YbGNVyIgp9I
Day 5: flew to Vieques, surveyed on Vieques from a temporary base
Day 6, 7, 8: surveyed points on main island of Puerto Rico using VRS. Very difficult due to narrow roads and jungle foliage
That left the island of Mona. A permit is required to visit the island, which is controlled by the Puerto Rico Department of Natural and Environmental Resources. Access is by boat. A few rangers are stationed there, and hunters are there this time of year. I got a quote from one of the charters in the area. $5000. an extra $1000 if we got stuck there overnight due to weather. Seemed excessive. And the seas can be rough, it is located halfway between the western side of Puerto Rico and the eastern tip of Dominican Republic.
On my flight to Vieques there was only one other passenger, and he was familiar with Isla de Mona. He said that the Puerto Rican DENR flies a plane out there every Wednesday to swap out rangers and to take food, etc.
That led to me chartering a flight from the company that does it for DENR. The DENR has a Cessna Caravan, but it is getting its engine overhauled so they charter an Islander every week from Air Flamenco. Because I needed to be there several hours to survey, I could not go with them on the Wednesday flight. So I set it up for a Thursday a couple of weeks ahead. A bit of a risk because they can only fly VFR. And I didn't yet have the permit. Normally visitors are only allowed to come by boat. A hunter was lost on the island, so they were hesitant about the permit. Had to get a flight manifest, get the USGS involved, etc. I flew to San Juan the day before my scheduled charter flight . and only got the permit finally approved as I was on my way from Charlotte.
The next morning I took an uber over to the downtown airport and we took off about 7 AM in an Islander (twin engine). We flew along the north coast of Puerto Rico for about 40 minutes, and then across the open water. The approach and landing to Mona was pretty cool.
When we landed, nobody was around. So we walked about a mile to Sardinera Beach where the rangers lived. They said all of their vehicles were down, so that was why they didn't come to meet us. On the walk I saw a few 4 foot Mona Iguanas, one was really close...
I had to survey 5 points there, plus I occupied a tidal benchmark that also had an OPUS share solution. I did an RTX occupation on that mark, which was 975 9938 A (PID DN8586). It is at the far left corner of this pier on the west side of the island.
Once I transformed the ITRF position to NAD83 (2011) epoch 2010.0 it hit the OPUS SHARE solution under 2 cm horizontal and -3 mm vertically on the published PRVD02. After that I surveyed a few points at the far end of the runway, and found that there is a CORS on the side of the runway. Everything I could find says it was decommissioned, but it looks like it is functional, grass was mowed, solar panels looked good, satellite comms looked functional. But I couldn't find any current data, so I wound up using one CORS in the Dominican Republic and two in Puerto Rico to position a base that I setup.
That is very cool!
It is interesting that you mentioned Mona Island. The New York Times has a story dated 5/30/2024 about its strange allure: https://www.nytimes.com/2024/03/20/magazine/mona-island-puerto-rico.html?smid=url-share
John Hamilton's project sounds like a doozy!
Wow! I love reading these types of surveying adventures. Thank you for sharing!
Wow, I hadn't seen that article, thanks!
That's one of those projects that memories are made of. Looks like a tight schedule, it's a shame that you did not have the time to do some exploring.
Yeah, it was so hard to get the permission, and to get there, that I regretfully didn't have time for anything else. Having the charter plane waiting for me was a bit of pressure. The pilot walked with me to the beach, as he is buddies with the rangers. I stopped and talked a bit with them, and they still had not found the missing hunter, after a week or so. As the NY Times story says, there are plenty of dangers there. Just flyin in I could see high vertical cliffs, and it would be easy to fall over one and die. Or fall in a cave.
When we were ready to leave it started raining, with low clouds, so it started looking iffy as to whether we would be able to fly back to San Juan VFR. But we made it flying low the whole way back, about 1000 feet MSLThey recently had Starlink installed at the ranger's buildings, so at least we were able to check the weather. But of course there is no cellular nor Air Traffic Control radio out there.
The big surprise was the CORS, I knew there was one there in the past but it is listed as decommissioned. But it sure looks functional. A friend who is an NGS Advisor says that he noticed on OPUS some submissions from there recently. But finding out who has access to it has been elusive.
I couldn't read the article, it's a pay wall thing for me. The decent on the approached looked a little dicey.
If it's so hard to get permits to get on the island, what was a hunter doing there? Doesn't seem that there would be much to hunt there.
Apparently they encourage hunting because there is an overabundance of feral goats and pigs. Probably seasonal, I think the summer is for camping and then there are no hunters.
Not sure how they were searching for him, they said all of their vehicles were broken down. I always carry a Zoleo now...'cause you never know.
https://www.zoleo.com/en-us/satellite-communicator
For a while I had an Iridium Go which is sort of like a hotspot but also has voice, but the voice quality sucked so I gave up on that. Haven't tried it for a few years, maybe it has improved.
What are the subscription fees for the Zoleo?
I pay $20/month for basic service, which gives me 25 satellite messages a month. But, as long as it is connected to cellular or wifi, those messages are unlimited. So the only ones that count against the 25 are when there is no cell or wifi. Also has unlimited checkin messages.
I also have a Garmin GPSMap 66i, but it does not have the capability to send over cell or wifi when in range.
