How to differentiate Wide and MegaWide Navigation Charts?

TZ Charts online catalog offers a large range of navigation charts. To help you find the chart you need among the more than 250 up-to-date available references, charts are classified through various criteria such as Data Type, Chart Size and Manufacturer.

In this article, we are going to have a look at the different chart size options. Based on your project, the type of sailing or the level of comfort you require, the kind of chart you will need can vary. So it is important to first define your needs and then find the chart that meets your expectations.


On one hand, Wide and MegaWide terms are commonly used by cartographic data providers. They plainly describe the size of navigation charts. An easy way to remember the difference in size is that MegaWide areas are approximately 3 times bigger than Wide ones. For both Wide and MegaWide navigation charts, the size varies according to the geographical coverage and the number of charts included within each area.

Below, you have an example of Wide navigation chart, composed of 3 small charts, for Mediterranean Sea from Gibraltar Strait to the west coast of Italy. The chart reference is “WRMEM32MAP6.1”.

On this next screenshot, the chart is a MegaWide type and it covers the entire Mediterranean Sea. It is composed of 7 charts, including the 3 charts from the Wide one above. The reference of this chart is “MWRMEM23MAP6.1” and goes from Gibraltar Strait to the Red Sea.


On the other hand, Wide and MegaWide charts have the exactly same data. The only difference is the size of the chart! Whichever zone you choose to buy a Wide or a MegaWide navigation chart, you will be able to download the following components:

  • Charts (Raster or Vector)
  • 3D Data
  • Photos

All the data you have to download is displayed on a table within the online chart catalog and each one has a “More Info” link with precise information such as Description, Download Link, File Size, etc.

File List example for the WRMEM32MAP6.1 navigation chart

3D Data and (Satellite) Photos are important data but they are not compulsory to navigate with. Having said that, it is still highly recommended to install them as together they provide more information and a different way in which to visualize this data. If you are used to navigating around coastlines, 3D Data will give you a better view of the objects and obstacles in front of you. Furthermore, (Satellite) Photos give you details of the coast, assists you for more precise navigation and they are very helpful to find the best mooring spot. If you want to learn more about the chart data integration in TIMEZERO navigation software, click here.


All navigation charts are updated at least once a year. For Raster charts, MapMedia orders all available charts from each local hydrographic service provider every year in order to scan and convert them to its unique mm3d format. For Vector charts, MapMedia retrieves the cartographic data from its providers, currently C-MAP and Navionics, and converts it to mm3d as well.

Our charts available for TIMEZERO software are available on the TZ Charts online catalog. If you want to see which chart(s) you need for your next trip, please click here:

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