Mobile Crossing WayPoint Map Loader Instrukcja Operatora Pobierz pdf (Strona 15)

SeaMarks manual III USING THE PROGRAM •

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missing any points.

An easy way to get started with maps is to pan and zoom a chart to show what you want on the map and then use Chart

Operations>Make this chart into a Map. This brings you to the Create Map screen with the map borders already

determined. Keep in mind that the screen is landscape orientation and the map will likely be portrait orientation.

For convenience, you can show the outlines of all your maps on the screen or paper at the same time with Map>Show

All Maps>Show all in Folder. This will let you see where your coverage may be lacking and helps you find a

specific map you may be looking for

9. Setting up to print your book

To begin making a book of your fishing spots, you need to plan how your data is to be organized. You could put

everything in one huge file or split it up into zone or regional files based on which inlet you would use for the area.

Alternatively, you can split the file on reef lines or depth zones such as: 60 ft reefs, 90 ft reefs, etc. Then you can

organize the files by use of the File>Split or File>Combine capabilities to make the individual files.

Next, you would make a set of maps to best display the data for each file in your book. To make printing the maps

easier, the program allows batch map printing from a list (see reference, chapter VI). Make a separate list for each

waypoint file. Finally, print the listings and maps from the lists. Remember that the printed page has its own

organization and does not necessarily follow the way you set up the screen display. Use File>Printing Format to

arrange how your data will be placed on the page and use File>Printing Format>Print Preview to verify that it will

print the way you want it.

10. Converting from Loran to GPS and back

The program automatically converts Loran waypoints (TDs) to GPS (Lat/Lon) as they are added to a file. In the event

that it cannot, the usual reasons are that the number is mistyped or the waypoint is very far from the center Lat/Lon.

During data entry, if the program can't convert a waypoint, it may bring up a warning that something is wrong with the

waypoint and show you a typical value it is comparing against. Once the problem has been corrected, the Lat/Lon

should appear in the spreadsheet display as each waypoint is entered. The first Display option under the Display menu

selection shows TDs and LL (loran and GPS) and is the ideal choice while entering loran data.

If waypoints are entered as Lat/Lon, they are automatically converted to the appropriate Loran numbers if the check box

on the ADD WAYPOINTS screen is checked. If you enter waypoints as Lat/Lon and they are not converted to TDs and

you later want to convert them, use the TOOLS>CONVERT To Loran (to any Loran chain) routine.

11. Calibrating the Conversions

Converting Loran to Latitude and Longitude involves complex geometry that the computer can handle with great

precision. The difficulty is that the Loran waypoints, while stable and repeatable, are not accurate in a geographical

sense. They can be as much as a half-mile off from where they should be based on the distance to the Loran stations and

the speed of light. In the 1980s the US government published tables of correction factors (called ASFs) to fix this so that

their maps could be shown with the corrected Loran lines on them. The program has the full set of those tables built-in,

but they are only good for about 250 ft of accuracy. These tables cover only 7 US loran chains and only over offshore

waters and the Great Lakes.

To get closer to the repeatable accuracy that we experienced with Loran, the tables can be improved by calibration.

Some areas have been already calibrated through use of customer supplied data. You can do this yourself by training

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Mobile Crossing WayPoint Map Loader Instrukcja Operatora Strona 15