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U.S. - Canada ENC Overlap

To comply with internationally agreed practices, Canada and the United States of America have agreed to eliminate overlapping coverage of Electronic Navigation Charts (ENCs). This new ENC coverage scheme will result in each country changing their areas of coverage, so that only one country’s ENC would be available for any given area at a particular scale.  

These changes to coverage come into effect 0000 Coordinated Universal Time (UTC), on 28 February, 2013. 

When the revised ENCs are available to the public a Notice to Mariner will be issued.

Please submit any questions or comments on our inquiry page.

This annex focuses on the ENC overlaps that are part of the Great Lakes.   The annex shows a graphical representation of the ENC coverage “before” and “after;” and lists the official revised ENC limits as agreed upon by Canada and the United States. 

NOTE:  Due the amount of coverage in the Great Lakes, this annex will only focus on affected areas and their products.

 

The following represents the ENCs that are affected by this project:

Annex A - Great Lakes

Cell Name

Producing Authority

Title

Band

Scale

CA173289

CA

Lake Superior/Lac Superior

1

600,000

As CA173289 is the same scale as US3MI79M, Canada will cancel CA173289 in favor of US3MI79M, which will become US2MI79M.

Cell Name

Producing Authority

Title

Band

Scale

CA273095

CA

Lake Huron/Lac Huron

2

400,000

CA273097

CA

Georgian Bay/Baie Georgian

2

200,000

CA273094

CA

Lake Erie/Lac Erie

2

400,000

CA273096

CA

Lake Ontario/Lac Ontario

2

400,000

US2EC03M

US

Cape Sable

2

1,200,000

 

 

 

 

 

US3MI79M

US

Lake Superior

3

600,000

US3MI80M

US

North End of Lake Michigan

3

240,000

US3MI60M

US

Lake Huron

3

500,000

US3OH03M

US

Lake Erie

3

400,000

US3NY21M

US

Lake Ontario Metric

3

400,000

 

 

 

 

 

 

 

 

 

 

Within the Great Lakes region the majority of the ENC overlaps are at the Band 3 navigation purpose.  This is a result of Canada and the United States Canada utilizing different scale ranges for their ENC navigation purpose.  The following graphic shows the current overlap at Band 3 between the United States and Canada.

*Note: Mouseover images to see changes to ENC Coverage


As the Great Lakes region is a relatively isolated body of water, the United States will move its Band 3 ENCs to Band 2 to better align with the Canadian ENCs at that same scale.  This will eliminate any overlaps at Band 3 - however, it will cause new overlaps at Band 2.  However, these new overlaps will be between ENCs that represent similar coverage and similar scale.
As a result of this change, all navigation purpose 3 overlaps are eliminated and we are dealing with newly created overlaps at navigation purpose 2.

As a result the following ENCs will overlap:

Cell Name

Producing Authority

Title

Band

Scale

CA273095

CA

Lake Huron/Lac Huron

2

400,000

US3MI60M

US

Lake Huron

3

500,000

CA273097

CA

Georgian Bay/Baie Georgian

2

200,000

 

 

 

 

 

CA273094

CA

Lake Erie/Lac Erie

2

400,000

US3OH03M

US

Lake Erie

3

400,000

 

 

 

 

 

CA273096

CA

Lake Ontario/Lac Ontario

2

400,000

US3NY21M

US

Lake Ontario Metric

3

400,000

The United States will retain responsibility for Lake Superior and Lake Huron and Canada will retain responsibility for Lake Ontario and Erie.

As a Result the United States will cancel US3MI60M and re-issue it as US2MI60M with the revised extents cut back to account for CA273097 (Georgian Bay) and Canada will cancel CA273095.

The United States will cancel US3OH03M and US3NY21M

Cell Name

Producing Authority

Title

Band

Scale

CA473305

CA

Long Point Bay

4

50,000

US4NY38M

US

Buffalo to Erie

4

120,000

 

CA473277

 

CA

 

Upper Gap to Telegraph Narrows

 

4

 

30,000

CA473276

CA

Lower Gap to Adolphus Reach

4

30,000

CA473036

CA

Carleton Island to Charity Shoal

4

30,000

CA473025

CA

Grindstone Island to Carleton Island

4

25,000

US4NY20M
CA473034

US
CA

Lake Ontario Clayton
Summerland Group to Grindston Island

4
4

80,000
25,000

The first overlap in Band 4 occurs between US4NY38M and CA473305 in Lake Erie.

As a result, the United States will cut back US5NY38M to the extents of CA473305 due to coverage being in Canadian waters.

*Note: Mouse-over the image to see the changes.

Usage Band 3

The next set of overlaps in Band 4 occurs in Lake Ontario between US4NY20M and CA473276, CA473036 and CA473025.

The United States will cut back US4NY20M to the extents of CA473276, CA473036, and CA473025 due to coverage being in Canadian Waters and CHS producing a better scale product.

Usage Band 4

Cell Name

Producing Authority

Title

Band

Scale

CA573012

CA

Lower Niagara River & Approaches

5

20,000

US5NY31M
CA573010

US
CA

Lower Niagara River
Welland Canal

5
5

30,000
15,000

CA573385

CA

Twyning Island Bridge

5

10,000

US5MI62M

US

St. Mary’s River, Lake Numuscong to Sault Ste Marie, Including Lake George

5

40,000

US5OH10M

US

Islands in Lake Erie

5

40,000

CA573326

CA

West Dock

5

4,000

CA573099

CA

Scudder

5

3,000

The next set of overlaps occurs in Band 5 in the vicinity of Niagara Falls.  US5NY31M overlaps with CA573012 and CA573010.

Canada will cancel CA573012 in favor of US5NY31M and the United States will cut back the extents of US5NY31M to the extents of CA573010.

Usage Band 5

The next set of overlaps occurs in the vicinity of Sandusky, Ohio on Lake Erie.  US5OH10M overlaps with US5OH12M and CA573326 and CA573099.

Canada will move CA573326 and CA573099 to Band 6 and cancel the Band 5 coverage and the US will eliminate its internal overlap with US5OH12M.

The final set of overlaps occurs in the Upper Peninsula region of Michigan.  US5MI62M overlaps with CA573385.

As a result the United States will cut out a hole in US5MI62M for CA573385.

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