Monday, June 18, 2012

Local Notice to Mariners Web-based Google Map Mashup (ChUM)


Chart Update Mashup

I've been working on this project for the past few months and now am ready to blog about it!

After first learning about Local Notice to Mariners and getting completely confused with where it was, how to find it, and how to understand it, I took my notes then came up with the idea to create a web accessible one-stop shop to make it trivial for mariners to view the critical chart corrections in context with a nautical chart.

After realizing how  and how often charts are updated and that it is important to keep both paper and electronic charts up to date, this project seemed like it could really benefit mariners in a big way. This is such a big deal that the Alliance for Safe Navigation's website has a pop-up upon entering the site that says:
"Getting chart updates is inexpensive and easy"
 (They also have on their home page a text box that allows you to enter your chart number and it will take you directly to the OCS Local Notice to Mariner table...I show that below, and I didn't find out about this website until well after I started my project!)

You can find the working prototype of my application here:


If you do a search for Local Notice to Mariners the first link you'll find (or at least I did as of today) is:

Then you have to click on the area you are interested in: District 1 for me.
Then you get:

You find the latest one and the pdf will look something like this (the one marked with "New!") - the chart corrections section (IV):
Not super intuitive (at least to the newbie), and since I didn't memorize the chart for my area of interest I would need to go look up the chart.  

I just want to mention that in that initial search for Local Notice to Mariners, the first one that doesn't have a website is the Office of Coast Survey link:

Which brings you directly to this:
(BTW, it took me a while to figure out the relationship between the navcen website and the ocs website, I wasn't sure why it was being posted differently in two places at first)

So, I hit accept and get this page:
But I have the same problem, I don't really know what chart number I need, just know the area, at least this page gives a link to a Catalog, so I follow the link:

And I zoom to and select my area of interest:

Now I see that Chart 13285 is highlighted! Now that I know my chart number I'm temped to go directly back to the previous page where it asked me what chart number I wanted to search for, but instead I read the whole page to see if there is something there. It takes some reading, but I see below some seemingly related links:
  • View Online
  • Notice Listing
  • Download RNC
  • Order Paper Chart
All I want to do is view the chart online and view the associated Local Notice to Mariners. So I click the View Online link to see the chart:
This interface isn't my first choice, I was able to completely loose the map (I guess by zooming out too much), I can't make it full screen so I'm loosing lots of real-estate and can never get a large area very big.

Not if I want to see the updates for this chart since it's last printed edition I can either go back to my previous link from the catalog viewer, or if I'm patient I can see that now in the upper right corner there are three related links:
  • Download RNC
  • Notice Listing
  • Find A Chart Site
This time I click on Notice Listing and a new pages opens up to this:
Nice a table, much better than that pdf table, but in the Disclaimer below it you'll notice it states:
  1. It is not a substitute for that pdf we found earlier.
  2. The info in the table is derived from the CRIT database (Critical Chart Corrections only...which is just section IV of the pdf)
  3. The updates only go back as far as Jan 2000.
I'm expecting the columns to sort when I click on them, instead I get information about what each header means (yes all of the columns link to the same page).

Because I struggled with this for a while, listed above is definitely the shortened, organized version of my struggles. (But I wanted to spare you the gory details).

Proof of Concept

All of this got me thinking, it would really be much more effective if the information was given in context so I could sort through the stuff that I wanted and be more in control. That's what we expect from the awesomeness of the web these days right?  

So, I just took everything I've shown above (except the pdf) and put it all together in the context of a Google Map (using V3 of the api so it will be mobile ready). Tried to put it all together in an intuitive, easy to use and access way so viewing charts with updates would be a one-stop-shop.

BTW, I also added the Coast Pilot which you would normally have to access at:

And all the lat/long positions and some of the locations are geo-coded so if you click on the links they will take you to that location in Google Maps.

The Future of Local Notice to Mariners

Hopefully, this work will inspire some dialog within the respective departments about tagging data so it can be useful to developers (who will in turn make it useful for the public), and making sure that EVERYTHING that can be will be Geo-Tagged! Right now it is all done by my code behind the scenes, how fast and great would it be if it was already done!

NOTE: the disclaimers from OCS still apply to this data/web is their data!

Let me know what you think about this project!

You can find the working prototype of my application here:


  1. Hi Briana, I'm Dave Rogers, formerly a Sr. Fellow from CMU Resch Institue.
    I firnd your work not just, but rather extremely interesting. I see you have no comments,, well, I hope that I can 'kick-off' a few. A colleague from CMU anjd I have been developing an "Assistant Naval Navigator' or ANN system for about a decade now. Our main focus, initially is the area of recreational boating and small commercial vessel activity within the International Line (12 nautical miles (nm) and about 100 nm along shore in high traffic, accident-prone waters, usually found around urban areas, select of the 327 US Ports-of-Call, and Points of Interest (Amusement Parks, State Parks/Beaches.
    You see, our missions are: 1.) Prevent fatalities and serious injuries due to recreational boating accidents (about 650 and 3.500/yr., respectively per USCG Boating Statistics) anjd 2;) Provide recreational owner/operator facitity for assisting DHS in their Small Vessel Security Strategy (SVSS) by equipping the boaters with capability to observe for potential situations that may be related to attacking US shore-based assets and Urban areas.

    I'm not going to go into more detail, but I will indicate your work is extremely important to us. ;For example, one recent USCG District Report indicated that there was UNEXPLODED ORDNANCE off-shore Virginia. Fortunately,
    nooe 'got a bang out-of that.' HAR HAR!! Anyhow, let me send your a copy
    of our IEEE paper about the ANN System. In fact, if you have a 'consolidate write-up about your effort, I'd like to add it to my library of good things - my email is When you send me something, I will send
    our paper. Actually, I check back on this website and see if yours is part of this. At any rate, happy sailing, a bit cold off-shore NH, but we're brave Northerners, Right

  2. Hi Briana -

    Just wanted to add a public note to commend you on the great work you have done.

    What I would do to have the resources of a University & NOAA behind me!

    Here in Australia we've created a simple version of NTM's on Google Earth at It only covers the State of Queensland (which is about 4000 miles of mainland coastline plus islands, and includes the Great Barrier Reef) and it's an after-hours exercise for our team of 1!

    Unfortunately charts are not provided by the Govt here, and nor are any data feeds, but here's hoping your work will inspire the powers that be to realise the benefits these things can bring to the boating community.

    Best regards,
    Chris Mills
    Linx Software