Expedition Navigation Software 
1 of 1- DuncanR
- Expert
Offline - From: Up and down East Coast Aus
- Registered: 9/16/2015
- Posts: 470
Chart boundaries, but which ones?
On the E Coast of Aust, many of us are preparing for Sydney-Noumea in June, followed later by the Groupama Round NC Race. For the latter race there is a requirement for paper SHOM (Fr marine) charts, pretty uncommon in Aus even at the usual suppliers.
So I am trying to work out the relationship between SHOM and BA charts for NC waters.
What are the chart boundaries showing in NC waters in CMAP M charts?
- us7070
- Expert
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- Registered: 12/06/2017
- Posts: 260
Re: Chart boundaries, but which ones?
DuncanR wrote:
On the E Coast of Aust, many of us are preparing for Sydney-Noumea in June, followed later by the Groupama Round NC Race. For the latter race there is a requirement for paper SHOM (Fr marine) charts, pretty uncommon in Aus even at the usual suppliers.
So I am trying to work out the relationship between SHOM and BA charts for NC waters.
What are the chart boundaries showing in NC waters in CMAP M charts?
I am in the USA and don't have charts for that area...
But, in general., when using C-Map charts in exp, if you right click anywhere on the C-Map chart.., and select Query Chart Objects > Data Source.., it will tell you what paper/raster charts were used to make the C-Map Vector chart at that location. if you have chart outlines displayed in C-Map.., it should be displaying the chart boundaries of those charts.
I have seen a bit of an issue where C-Map uses more than one source for an area - say mostly British Admiralty.., but with US NGA in a few spots.
- DuncanR
- Expert
Offline
- From: Up and down East Coast Aus
- Registered: 9/16/2015
- Posts: 470
Re: Chart boundaries, but which ones?
Thanks US, I'd completely forgotten about that. In one chart area, so there is a correspondence with SHOM 2732.
"IN THIS AREA, BATHYMETRY IS DERIVED FROM FRENCH SURVEYS CARRIED OUT BY SHOM UNTIL 1993 AND BY ORSTOM UNTIL 1992, FROM BRITISH ADMIRALTY CHARTS PUBLISHED UNTIL 1994, THE GEBCO AND MISCELLANEOUS LINES OF SOUNDINGS.
SOURCE INDICATION
FR,FR,GRAPH,FR273210
SERVICE HYDROGRAPHIQUE ET OCÉANOGRAPHIQUE DE LA MARINE (SHOM) - FRANCE"
More interesting, in anoter area close by, the following: "THIS CHART MUST NOT BE USED FOR NAVIGATION IN THE LAGOON: BATHYMETRY HAS BEEN SIMPLIFIED AND BUOYAGE IS NOT CHARTED."
I'll be awake for that bit ....
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Thread Starter- us7070
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- Registered: 12/06/2017
- Posts: 260
Re: Chart boundaries, but which ones?
I just did the Caribbean 600 - there are many areas where the C_Map charts have this message:
"INADEQUATELY SURVEYED AREA. POSSIBLE EXISTENCE OF NOT CHARTED SHOALS."
Anyway, I make it a practice of looking at that chart info on all my charts.
Last edited by us7070 (3/28/2018 2:09 am)