Plans for Iqaluit.

John HC and Ian C.

frob
20m res. view of the Inner Frobisher Bay.
 Travis,

The CHS single beam sounding data that was in NTX was converted to ASCII by Ian.

You can get a copy of the lat-lon-depth files (~20Mb) here.

As you can see the main CHS digital depth contribution is the approaches to the town that almost entirely overlap the areas that Don Forbes in requesting in his KMZ files (Iqaluit priority 1, 2 and outer).

I've gridded the data up as a Mercator projection and a tif and txt file is available here:


Yuo should be able to bring that into Aldebaran and design surveys based on that (see suggestions below).

As to the approaches - well right now they are TTOALLY blocked by ice. But if Cecil attempts something, I'd really like you to run a little t othe east of the Amundsen cummulative corridor to find the 200m contour.

And if Cecil is even prepared to try it, I've got recommendations (see below) for two alterate approaches to the Inner Frobisher Bay.
iqal
5m res. view of the area where the CHS soundings exist.
 chs sound
5m res. interpolated DTM based on the CHS coverage
(black contours are drying line and 50m intervals below.
White contours are 10m intervals)





Alternate approaches.
 Illustrates the three possible incoming track to use. Not sure how frequently used are Algerine Passage and Fletcher Channel. They clearly both have been covered by CHS (non-digital) soundings. The approach to Algerine is through sparsely charted water. It may be too deep for the EM3002 for much of the way, but you can shift to the east to find the 200m contour. Expect plenty of bedrock surprises though.

All may be a mute point if the ice is still there.

going through any of the channels will be tricky as they all have strong (5 knots!) tides and if ice is being squeezed through, that won't be a good combination!.

If you have to wait outside the channels for the ice to clear, I would REALLY like you to build a shipping corridor toward Algerine Passage even if you don't actually go through it. The poorly mapped (apparently mainly  deep - but reported PA shoals...)  area to the north east of the Amundsen corridor would make a great contribution to charting.
Don's wishes.
 Showing Don's 3 kmz file requests. And the stars are my eyeballed shifting of the off datum 1967-1976 grabs.  As you can see, the area requested includes lots of intertidal areas!.
plan over chart.
 Details of proposed simplified plan. Shown over the official chart (well 7122, I should have used 7127 probably).

Note two main corridor approaches along the deepest point. Expand on these corridors using free hand line running for as much time as you have.

Two box areas.
Only atttempt Box 1 if it is close to HW. The awash rock shown on the chart does not appear in the CHS sounding data. I'm honestly very nervous  about attempting this area at all, but it contains two of the grabs that Don and Trevor want to cover.

Perhaps examine the area at LW first to see if you are comfortable.

Box 2 can be attempted at any stage of the tide as it is very deep. Only build up to ~ the 10m contour.
over soundings
 Same plan, but superimposed over the CHS grid. As you can see we are adding nothing new for the CHS alas. But we will get subbottom and backscatter and high resolution topo for the science types.

As you come into the inner bay, see if you can walk as far away from the existing Amundsen coverage as possible. The CHS data in the outer bay (see map at top left), just slightly expands this.