[GPSNavX]

The S-57 ENC is a complicated data structure with many intricacies. Over in the MS Windows world 7Cs provides the tools to create S-57 ENCs and read and display them. Unfortunatley those same tools are not on Mac OS X. So back in 2005 I began the steep learning curve of figuring out the S-57 ENC data structure. After almost two years of working with this format I learned a lot. From that information I have developed a new S-57 rendering engine for MacENC. It is faster and provides much more detail than before. This new rendering engine will make its way in the next release of MacENC which will be released early next week.

[ReeferJon]

That sounds great. I volunteer to test it on my Navionics UK S57 charts!

Will the new engine use standard marine symbols for buoys etc? This is one of my only issues with the rendering of the current engine; you can't tel the type of the buoy by looking at the charts.

To my mind a digital chart should try and match the conventions of paper cartography where ever possible.

[GPSNavX]

What gets rendered is purely up to the application or more specifically MacENC. S-57 ENC is a database made of of objects and attributes. Those attributes describe the geographical location and the physical elements of the object. There are no predefined images in the S-57 ENC database. Its respective records are full of numbers.

With a paper chart (and for the most part a raster chart) ALL information must be put on the surface of the paper. A kind of what you see is what you get approach. There is no additional information than what is printed on the chart.

With an S-57 ENC chart there are three dimensions. The surface/screen and then the ability to query any object on the chart. So the rendering does not need to put ALL attributes right on the chart as less important details can be queried for by simpling clicking on the object (i.e. buoy) and a whole list of attributes is displayed in the Navigation panel.

MacENC does attempt to show the more important attributes of an object right on the chart. For example its geographic position, its color, its geographic size. Since MacENC has to run on the older G4 Macs and small screen laptops rendering performance is key as is avoiding clutter on the chart. MacENC uses a consistent model for rendering navaids such as buoys.

The new rendering engine does enhance the drawing of navaids with the addition of light characteristics (i.e. QFl 3s) to the name label and buoys are round and beacons are square. These navaid labels are displayed when the zoom scale is 1:15,000 or larger OR the cursor is hovered over the navaid.

Other objects such as anchorages, pipelines, buildings, obstructions are rendered on the MacENC chart consistent with paper charts.

To get an idea of how many objects and attributes there are in the S-57 ENC database go to this site..

http://www.s-57.com/

Objects (i.e. obstruction) are on the left column, and Attributes (i.e. color) are on the right column.

[ReeferJon]

I don't dispute any of the points that you raise above. In fact I wholeheartedly agree with you; my post wasn't to reopen the old vector vs raster debate. An S57 file can almost be regarded as a huge object-orientated database of marine information, of which a small subset (the most essential and relevant) is rendered in the form of a digital chart by MacENC (or similar software) with other information available for "drill down".

However, the point I'm making is that this rendered manifestation of marine data is presented and interpretted by the user as a "chart", and there are international conventions for for displaying marine cartography, particularly buoyage. These conventions have developed over the last few centuries with the sole purpose of providing a clear and unambiguous representation of the marine landscape; and they type of buoy it is, to my mind falls under your definition of important information.

http://www.charts.gc.ca/pub/en/products/...ctionQ.pdf

Let me give an example .

Without appropriate international "cardinal" symbol

The buoy is displayed as a yello square. The user has to click on a yellow buoy and scan through it's attribute properties in a window to see whether it's a north, south, east, or west cardinal in order to see where the danger is and to which side of it they should pass (pretty important!). If MacENC is being viewed on a cockpit monitor in a rolling sea, this would be difficult.

With the appropriate cardinal symbol

The user looks at the buoy on the chart, and see immediately from it's symbol in which direction the hazard lies (the vital data). However if they do want to find out more information about the nature of the hazard, they can still click on the buoy and view it's attributes.


The majority of vector cartography software vendors (CMAP, Navionics, MaxSea, Raymarine etc) adhere to these conventions when rendering charts because they're universally accepted. I might be wrong, but I believe that they are even mandated as a standard for ECDIS systems.

What I would personally like to see is, within the preferences window of MacENC, the ability to choose the flavour of symbology displayed, be it the US standard, IHO standard or, for underpowered users, the current MacENC standard. Presumably, a large chunk of the development time would be to encode the relevant symbols into a library in the relevant vector format (maybe SVG or something..?). I'd be more than happy to do that for the IHO ones if it would help.

I'm a massive MacENC fan, and I genuinely believe that its up there with the very best that the Windows world has to offer. However it's chart rendering, to my mind, isn't as clear as some of the other S57 products on the market which use the international conventions.

Of course that's just my opinion... ;-)

[Jade]

Setting the symbol representation discussion aside for just a minute, I must say that the rendering speed is significantly improved with this new "engine" and well worth the time spent to achieve this.

[cyberhusky]

I'm a massive MacENC fan, and I genuinely believe that its up there with the very best that the Windows world has to offer. However it's chart rendering, to my mind, isn't as clear as some of the other S57 products on the market which use the international conventions.

Of course that's just my opinion... ;-)

I join your opinion!
Viewing the buoys as symbols we are used to instead of looking up the properties in a separate window is tricky in regions with lot of ferry and cargo ships, as in the North-sea and UK Channel.
I would like to see future versions of MacENC support the international symbols at least for the most important symbols (cardinal, etc.)

Regards,
Manou

[GPSNavX]

Future versions of MacENC will render buoys and beacons consistent with recommended ECDIS standards.

[bobetter]

I'm a massive MacENC fan, and I genuinely believe that its up there with the very best that the Windows world has to offer. However it's chart rendering, to my mind, isn't as clear as some of the other S57 products on the market which use the international conventions.
Of course that's just my opinion... ;-)

I join your opinion!
Viewing the buoys as symbols we are used to instead of looking up the properties in a separate window is tricky in regions with lot of ferry and cargo ships, as in the North-sea and UK Channel.
I would like to see future versions of MacENC support the international symbols at least for the most important symbols (cardinal, etc.)
Regards,
Manou

Future versions of MacENC will render buoys and beacons consistent with recommended ECDIS standards.

I think it is fantastic that MacENC has plans to incorporate ECDIS standardized symbology. While the current library seems sufficient for navigational purposes here in the US, once Cardinal Marks are introduced the picture becomes a little less clear, as ReeferJon has pointed out. It should be noted, however, that even with a more traditional depiction of NavAids, there will still be a limit as to what info can be displayed on the chart proper and being able to "click and query" a mark to obtain it's complete list of characteristics will remain the best method of evaluating a particular item of interest.

[GPSNavX]

The IHO S-52 Presentation Library CD has arrived and good progress integrating the symbols into MacENC is occuring. As soon as integration is complete a new version of MacENC will ship.

[GPSNavX]

MacENC 4.50 will feature S-52 rendering. The integration is about finished. All registered users of MacENC will receiver MacENC 4.50.