The new free NOAA charts that Maptech has available for download are BSB, not BNC. BSB chart files are produced by scanning the paper charts and calibrating for lat/lon. The BSB chart is much like a .jpg file and is a picture of the paper chart. They are also called raster charts. The ENC's are digital files that contain codes that allow a computer program to draw the chart. In chartplotters that use CMap, Navionics and Garmin "chips" a similar process is used. These are called vector charts. I'm not sure one format is better, but apparently NOAA thinks the ENC format is better because they are in the process of converting everything to ENC. In time the BSB charts will be dropped and even the paper charts will be generated from the ENC database. Jim Fidler "Fiddlesticks" ----- Original Message ----- From: "Chris Byer" <1hirld302@sneakemail.com> To: <fidlerjim@earthlink.net> Sent: Friday, November 11, 2005 11:41 AM Subject: Re: GL: Adapting these free charts > Jim; > To the question: > "Is there anyway to adapt these free charts to a Garmin > chartploter(Bluecharts)?" > You responded: > "It would be theoretically possible for some computer genius to write > software to convert the free ENC charts..." > The free charts from Maptech are in "BNC" format. What is the difference > between "BNC" and "ENC"? Which format is better? > Thank you, > Chris Byer > 1hirld302@sneakemail.com

The data in a ENC chart file is the mathematical representations of objects. The file contains the position of the object (long/lat), type of object (bridge, marker, shoreline, depth, etc) as well as the characteristics of the object (color, label, etc) as well as layer information, links to picture files, frame of reference of the chart, etc. Upgrading the chart should be easy. For example, if the position of a marker changes, you only need to find the object in the file and insert the new co-ordinates. Likewise for adding and removing objects. There is no need to download a new file. It should be possible to have the Notice to Mariners automatically update your charts so that they are always current. Since the object text is a separate entity from the object, when in course up mode, the names/labels are displayed on your monitor correctly no matter what your heading is. Another interesting effect is that you can have lights flash in their correct Morse code and timing since they are an independent object from the rest of the chart. Another neat trick is that they have tied picture files to objects. When you click on a bridge (really just another object), a tiff file is displayed showing the bridge as it looks from both upstream and downstream, with clearances for each arch and a profile of the river bed under the bridge. It's also easy to manipulate a complete class of object (ie: hide all the depth contour lines, or all contour lines deeper than x feet, etc). You can also set up an alarm which will go off if you cross a depth contour line. Each ENC chart requires about 350 kb of disk space where a raster chart takes about 3,500 kb of disk. All of the ENC and IENC for the loop will take about 250 mb of disk. My raster charts for just Georgian Bay take up about 85 mb so you can imagine what the loop would require (mind you, you would probably leave the charts on the CD/DVD) Having said all that, I much prefer the look of raster charts, however, most charting software will allow you to split the screen and put the ENC chart on one side and the raster chart on the other. By the way, I had an email from Jeppesen Marine (Nobeltec) this morning, confirming that Visual Navigator version 8.0 does support NOAA S-57 ENC charts as well as the NOAA / NDI BSB raster charts. Steve Bottoms 42' Sealord Midland, Ont ----- Original Message ----- From: "Jim Fidler" <fidlerjim@earthlink.net> To: "Chris Byer" <1hirld302@sneakemail.com>; "great-loop" <great-loop@lists.samurai.com> Sent: Friday, November 11, 2005 5:49 PM Subject: Re: GL: Adapting these free charts > The new free NOAA charts that Maptech has available > for download are BSB, not BNC. > > BSB chart files are produced by scanning the paper charts and > calibrating for lat/lon. The BSB chart is much like a .jpg > file and is a picture of the paper chart. They are also > called raster charts. > > The ENC's are digital files that contain codes that allow > a computer program to draw the chart. In chartplotters > that use CMap, Navionics and Garmin "chips" a similar > process is used. These are called vector charts. > > I'm not sure one format is better, but apparently NOAA > thinks the ENC format is better because they are in the > process of converting everything to ENC. In time the > BSB charts will be dropped and even the paper charts > will be generated from the ENC database. > > Jim Fidler "Fiddlesticks" > > ----- Original Message ----- > From: "Chris Byer" <1hirld302@sneakemail.com> > To: <fidlerjim@earthlink.net> > Sent: Friday, November 11, 2005 11:41 AM > Subject: Re: GL: Adapting these free charts > > >> Jim; >> To the question: >> "Is there anyway to adapt these free charts to a Garmin >> chartploter(Bluecharts)?" >> You responded: >> "It would be theoretically possible for some computer genius to write >> software to convert the free ENC charts..." >> The free charts from Maptech are in "BNC" format. What is the difference >> between "BNC" and "ENC"? Which format is better? >> Thank you, >> Chris Byer >> 1hirld302@sneakemail.com > _______________________________________________ > http://lists.samurai.com/mailman/listinfo/great-loop