Originally Posted by yachtvalhalla
I've created these using GE images
for reference, thanks to GE2KAP. No guarantees and I'm open to corrections if anyone finds some.
Thank you for posting
these files, especially the spreadsheet.
I find the interactive process and opaque file manipulation somewhat error-prone. It would be useful to have an offset configuration tool that can produce and read back a text list of cells (maybe: positions/scales?) with offsets. It would be safer and also an immense help when comparing and merging offset data from multiple sources. Also, perhaps the description language might be rephrased towards the traditional way, more familiar to mariners (instead of "Y Offset" and "positive towards North" maybe "actual latitude is ... to North of charted position") ?
I think it would be good to flag user offsets applied on the chart in a readily visible way, so that thay are easier to spot than by going to Offsets Dialog. This would be important if offset files are to be given to someone else, who may not even be familiar with this Dialog... Otherwise one might misinterpret some Notes that are part of Chart Cells themselves, e.g. for Gaferut Island (happens not to be true in this case...)
Feature Class: CTNARE
Position: 009 13.8224 N 145 22.4532 E
INFORM (Rep to lie 2 5 miles west
Source date: 1971)
As I am in regular contact with a friend crossing the Micronesia right now, here are some on-the-spot reports, compared to respective Google
Earth coordinates. Only large scale charts
Pohnpei Kolonia - 6° 58′ N 158° 12′ E - on position - (GE: on position)
Ulul Island in the Namonuito Atoll - 8° 56' N 150° 4' E - lies 1.5 nm to W (275°) from CM charted position - (GE: lies 1.5 nm to E (100°) from CM charted position)
Gaferut Island - 9° 14′ N 145° 23′ E - on position - ( GE: lies 0.3 nm to SSE (160°) from CM charted position )
Near Gaferut anchoring
proved impossible due to currents and surf conditions, so estimate only...
For Ulul I requested double confirmation and got it ...
Another source, a blog from s/v "Quest" ( Kosrae, FSM
Kosrae Lelu entrance - lies about 0.5 nm to S from charted position - (GE: lies 50 mtr to SbW (200°) from CM charted position)
The s/v "Quest" report seemingly refers to a Navionics
chart, but I think the result would be similar with CM.
One can also find interesting data in the blog from catamaran
"Two Oceans" ( On in Micronesia « Catamaran “Two Oceans” Weblog
), e.g. for the Pioneer Pass in the Oroluk Atoll.