Computer Tips and Tricks
When we left the U.S. in 2007, the computer navigation
systems were running in the $2,000-$5,000 range. We just couldn't
afford that, and especially not two of them (every long range cruisers needs
critical equipment backups). We also could not afford to keep buying
map cartridges every time we moved a couple hundred miles--this is both a
cost issue and an access issue.
So our primary navigation system consists of the following:
1. A Garmin
GPSMap 76Cx on the helm (with maps installed).
Link to current equivalent
2. A laptop down below on the nav station, with a NMEA connection to
the Garmin, but also a USB backup GPS if we need it
3. A 15" 12-v (cheapo) LCD monitor on a swing out arm in the
4. A 'presentation
mouse' to manipulate the computer from the helm station. Note, there are
other much cheaper-appearing options on Amazon, however, most do NOT include
an actual "mouse" function. Most only have forward and back buttons,
good for slide shows, but not for mouse movement on screen. This
device also has a 60 ft range. Here's an alternative from Keyspan with
100 ft range.
Our original navigation laptop in 2007 was an old (purchased second-hand) Dell laptop.
It was a several thousand dollar laptop when new, but we bought it
'refurbished' for about $200. It doesn't need to be super-fast, and it
doesn't need much more than a 40-GB hard drive. It was running Windows XP.
The first thing we did was strip almost ALL of the software
off the computer. We disabled the wifi, and took off the anti-virus
and firewall, and made sure that NOTHING was being started by Windows at
computer startup. We also removed the 'user sign-in'. So, turn
this computer on, and it boots up immediately.
Then we carefully put ONLY navigation and 'underway'
applications back on it:
GPSGate to help manage the GPS and Serial Ports for several
navigation programs (optional)
(properly configured for our underway communications functions
Worldwide Tide Program (free)
- For transforming GPS waypoints and downloading to Garmin (optional)
A simple photo program of your choice (see
This computer NEVER connects to the internet... so it
doesn't need the anti-virus applications, Windows Updates, etc.
Making Charts from Google
Earth Using GE2KAP
Website URL for contact info and new versions of GE2KAP:
CruisersForum where Paul is answering questions and posting updates:
GE2KAP Facebook Group
If you like GE2KAP and use it, you should go
right now and buy Paul Higgins a
beer. He has spent a lot of time on this tool, and it is VERY useful to us yachties
in remote places. Just think of how much money you have previously spent on charts
and chart chips, and Paypal him $20. (Look for the Paypal link under
the picture on the home page. You can pay with credit card, don't need
The primary program I use here is GE2KAP. GE2KAP will interface with YOUR
copy of Google Earth, and take what is currently shown on your Google Earth
screen, and save it as a geo-referenced KAP file. KAP files are 'raster'
files and useable on most navigation programs, including:
Maxsea 10.3.2.1 (but NOT TimeZero)
The benefit of making chart files vs navigating IN Google Earth, which I
have already played with, is twofold...
1. You can use the built-for-navigating programs you are already familiar
with, and make routes and waypoints, etc without learning yet another new
2. Once you make a chart from Google Earth, it is there, no matter what
happens to your Google Earth installation or your GE cache file.
To use GE2KAP, you need to do the following:
1. Have a compatible version of
Earth installed (see Paul's download page for details).
2. Either have your installation of Google Earth connected to the internet,
or have the area you wish to make a map from (Google Earth content) cached
on your computer. (see discussions on cacheing
3. Have the program
installed on your computer. Paul Higgins says to install the 32-bit
version even if you are on a 64-bit Windows computer.
4. Have a subdirectory created to put the resulting charts (ie C:\Charts\GECharts
Note: On the original instructions (if you read the sailing forum Q&A, Page 1),
there are also two other requirements that are no longer needed with
the latest version.
(ImageMagick and libbsb)
Also, GE2KAP also works with another GoogleEarth-like
program, SasPlanet. SasPlanet offers alternative imagery, in case the
GoogleEarth image is of poor quality or obscured by clouds.
Once you have done all this, follow these directions:
1. Start up your Google Earth program (GE) and find the location you want to
make a chart of. Whatever is shown on your GE screen will go into the chart.
You DO NOT have to be hooked to the internet, if you have previously been on
the internet and cached (saved by displaying when connected to the
internet). GE will complain that it can't find the internet. Just tell it
OK, and NO you don't want it to help diagnose your network problems.
2. Make sure your display in GE has NORTH straight up. For some reason my GE
wants North at about 10 degrees (probably the tilt of the earth). You can
quickly orient to North straight up by double-clicking on the 'N' in the
navigation controls (normally in the upper right corner of the screen).
(Newer versions of GE2KAP automatically adjust this by default
before capturing the picture)
3. Clear the junk/menu overlayed on the GoogleEarth screen (using the View menu).
Anything displayed on the screen will go on the chart. So you want to turn
off unnecessary GE layers and the Navigation--if possible get to just the GE
picture. (You cannot get rid of the GE logo).
4. Start up GE2KAP as any normal program, from the shortcut on the desktop. If you have installed ooREX properly, it
should just run. What you should see are 2 screens, one a black DOS-type
screen which comes and goes, and one the user interface screen. It will say
'connecting to Google Earth'. If you have forgotten to start GE first, it
will start it for you. Then you can use GE as normal to display the place
you want to make a chart of.
To make your first chart you need to do 2 things:
a. Enter or browse to the chart directory where the new chart will be
placed, and include the filename. This goes in the Chart/Location name
Ignore the stuff in the lower half of the screen for now.
I think the folder you point to must already exist
b. Click the Create Chart Button. Voila, GE2KAP shows some progess in the
It is finished when it displays:
To View the output created press "View Chart"
To Calibrate another.. display the area on Google Earth.
Enter the name of the chart to create with its filespec below.
Then press the Create Chart button.
6. You can press the View Chart button, and it uses a simple KAP file viewer
to display what just got created. I recommend that instead you load it into your
favorite charting program and see how it looks.
Be cautious when first
trying to navigate with a new chart.
TRUST YOUR EYES NOT YOUR COMPUTER!!
1. Check out the HELP button. It loads some nicely done HTML help which Paul
has thoughtfully included in the zip file. (The button will try to load the
help from a directory named Help in the same directory as GE2KAP.rex
2. The bigger screen (higher resolution) screen you have to display GE on,
the more area one chart will cover at a given zoom level, AND the bigger the
resulting chart file. But I have been
making chartlets successfully on a 10" netbook laptop. Each chart
is about 500-700 Kb in size.
3. The overlay stuff on the expanded GE2KAP screen I haven't played
with, but I think it allows you overlay another KAP file onto the GE screen,
so, for example, you can create ONE CHART that has both the original chart
(with depths) and the Google Earth view. See
Valhalla's Web Page for Instructions.
4. DON'T FORGET to turn off Terrain in Google Earth when using GE2KAP or the
Geo-referencing may not be accurate on the chart produced.
5. Naming conventions - it is helpful before you start
out making charts of an area to come up with naming conventions. I
have ended up with over 100 charts of Fiji and ended up with a hodge-podge
of naming. Now when I create a new chart, I create it with the name:
This makes it easy to use Windows' 'sort on filename' to
group the related groups of chart files. You can also put spaces in
the filename--neither Maxsea nor OpenCPN cares, just keep the filename from
getting too long.
Fiji1.kap, Fiji2.kap, etc will make you (and/or people you
share it with) very unhappy in the long run.
6. When you are comfortable making charts, play with
the Historical View function on the View menu. Sometimes the current
view (satellite photo) on Google Earth of a particular location is not the
best for eyeball navigation. Sometimes, you can go back in time, using
Historical View, and find a photo that better depicts the location (the sun
angle is better, fewer clouds, etc).
Downloading the Charts we
have Already Made
More charts available here:
Valhalla's SE Asia Charts
Zen Again's Charts
If you like GE2KAP and use it, you should go online and buy Paul Higgins,
the GE2KAP developer, a
beer. He has spent a lot of time on this tool, and it is VERY useful to us yachties. Just think of how much money you have previously spent on charts
and chart chips, and Paypal him $20
Loading Raster Charts into Maxsea
1. File / Open (not Open Chart)
2. Browse to the directory (ie C:\Charts\GECharts)
3. Select any file (a new one you haven't previously loaded)) and
It should load ALL the charts.
To show the Raster chart window, use the menu item Window to switch back and
forth between the Raster Chart and the CMap (vector) chart. All your routes
and waypoints will be there! Unfortunately I haven't found a way to get the
Raster and the CMap chart to track together, but you can always use the
'center on my boat' button to center up both screens so you can compare
So far, in Tonga, Fiji, the Marshall Islands, and Micronesia, the GE Charts have been a godsend... spot on in Niuatoputapu and Vavau, where the CMap charts are running us over land.
Loading Raster Charts into OpenCPN
1. In the OpenCPN program, click the Wrench Icon, and
click the Charts Tab
2. In the upper part of the window, browse to where you have the Charts, and
select one of the folders. You should see the full folder path in the box
just below, something like this:
3. Click on the Add Selection button, and the folder will be added to the
'Active Chart Directories' box below. Do this for whatever charts you will
plan to use in the near future. Note that if you have chart sets
stored in subdirectories, OpenCPN (unlike Maxsea) will traverse the
directory tree and load up all the charts in the tree.
4. Click OK, and Open CPN will rebuild its list with your new charts
5. If you have 'chart quilting' turned on in OpenCPN, Play with the light
blue bars at the bottom of the screen to see which level of chart you can
6. If you have C-MAP CM93 charts loaded in OpenCPN
also, you switch back and forth between CM93 view and Raster chart view by
clicking between the blue-colored buttons and yellow/brown colored buttons
at the bottom of the screen.
See our full "Getting the Most out of OpenCPN" presentation
on our Presentations Page
GoogleEarth has a built-in 2GB 'cache'. What this
means is that it will save up to 2GB worth of images to your computer drive,
which are accessible in GoogleEarth offline, without being attached to the
internet. When you reach ~2GB, then GoogleEarth automatically
'manages' the space for you--removing older and/or seldom-visited images to
make space for new images. 2GB is actually a lot of GoogleEarth
images, but you can't guarantee that an image that was accessible offline
yesterday will still be accessible offline tomorrow.
I use a 'Google Earth Cache Management' program called
"Cache for GoogleEarth"
here. It mostly works for the intended purpose (but is a little
quirky). I have had no problems restoring a saved cache if I am
connected to the internet, but something in GE seems to go wrong if I try to
restore a saved cache while offline. Even with this quirk, this
program saves lots of download time on slow networks if you have the time to
pre-download caches on faster networks. (ie pre-download the South
Pacific Islands when in the U.S., in manageable chunks, then restore them as
needed while actually cruising the South Pacific.
You can also manually manage your cache files, and there are
likely some donation-ware versions of GE Cache managers.
Like this one.
I have not played with phiggins's GERoute, which is new, but it is a way
to force Google Earth to cache the files you will need for a particular
route. Once you have GE2KAP working, it might be worth playing with GERoute.
Converting from Maxsea
PTF files to GPX Files for OpenCPN
Do the conversion in GPSU
Do NOT save the PTF file!!
Open the resulting GPX file in Wordpad or other text editor
Search and replace the following:
<sym>265</sym> to <sym>anchorage</sym> (anchor)
<sym>120</sym> to <sym>diamond</sym> (blue diamond)
or <sym>xmred</sym> (red x)
or <sym>triangle</sym> (black triangle)
or <sym>scuba</sym> (Scuba Flag)
If left untouched, the 120 will translate to a black circle.
You need to search and replace:
<trkseg> with <trk><trkseg>
</trkseg> with </trkseg></trk>
s/v Valhalla's web page on Google Earth and Navigation
This page evolved over a period of time, his final solution ended up being