Chart Management

Introduction

HCRF format charts are far more complex than they might at first appear. As well as the actual raster image data, a substantial amount of other information (metadata) is provided in various files for each chart. There is also a catalogue that contains information about the entire chart series to which the chart belongs (ie, ARCS, NZMariner or Seafarer RNC).

Charts are updated frequently. When this happens, rather than issuing an entire new set of files for each chart, an Update CD is provided which updates only the relevant parts of an existing file. Update CDs are issued each week (ARCS) or month (NZMariner and Seafarer RNC), and contain the cumulative updates (if any) for every chart in the series since the last full Charts CD was issued. In the case of NZMariner, physical CDs are no longer used—you download the chart and update data from LINZ's website—but the file and folder structure remains the same.

PassagePlus provides features that help you manage your portfolio of ARCS, NZMariner and Seafarer RNC charts and keep them up to date. These features are accessed via the 'Chart Manager' button on the main toolbar.

Managing ARCS and Seafarer charts

1. Add chart permits

When you buy charts from an ARCS or Seafarer RNC retailer, you will be given a key called a Chart Permit for each chart. These need to be installed before you can install and use the chart. PassagePlus checks that the chart permits are valid before allowing you to install them.

2. Install new charts

Once you have installed permits for your charts, PassagePlus allows you to install the charts from ARCS or Seafarer RNC Charts CDs. It will also immediately bring them up to date using the Update CD that you will have received along with the Charts CD(s) and Chart Permits. Installation and updating are only permitted to the extent allowed by the Chart Permit.

3. Update charts

It is advisable to update your charts regularly (say annually). You can purchase updates from an ARCS or Seafarer retailer. They will provide you with a new Chart Permit for each updated chart plus the latest Update CD. After you install the new permits, PassagePlus updates the affected charts using the new Update CD. Again, updates are only done to the extent that your permit allows.

4. Check the status of a chart

The Chart Manager window shows the status of each chart you own (ie, for which you have a chart permit). Basically this shows whether you have installed the chart, whether you are permitted to open it, and whether it should be updated.

5. Verify the data integrity of a chart

This test can be performed at any time to check that the chart data has not become corrupted.

6. Remove charts

Charts are stored in compressed form and typically occupy about 2MB of hard disk space each. With today's high-capacity hard drives, it should not be necessary to remove charts to save space, but you can do so if you wish. If you do this, your chart permit is still saved, so you can easily reinstall the chart later.

7. Update the chart catalogue

An electronic catalogue of the entire ARCS or Seafarer RNC chart series is maintained on hard disk. It is used for various internal functions, primarily providing the data for the Chart Browser.

The latest catalogue is automatically copied to your hard disk whenever you use an Update CD for installing or updating charts. Thus, normally, the catalogue will be as up to date as your most recent Update CD. You can, however, update the catalogue from an Update CD as a separate operation if you wish. Most users will probably not need this feature.

Managing NZMariner charts

Although NZMariner uses similar file structures, there are far fewer charts in the collection (about 160, compared to over 3,000 for ARCS) and they are free to download. So you simply download the entire folio rather than individual charts. The necessary chart permits are included in the download and do not have to be provided separately. This means that chart management is simpler; several of the functions for managing ARCS and Seafarer RNC charts are not needed for NZMariner. You simply click the 'NZMariner' button and either install the entire collection using the downloaded Charts file or update the entire collection using a downloaded Update file. A new edition of the Charts file is generally issued annually (around August) and a cumulative Update file is issued monthly.

Status checking and data verification are the same as for ARCS and Seafarer (see 4. and 5. above).

To maintain the integrity of the collection, we have decided not to allow removal of individual NZMariner charts—the entire folio occupies only about 200MB.