For several years I have been creating and swapping GoogleEarth imagery for use in the free chartplotter OpenCPN. The imagery is captured using GoogleEarth and GE2KAP while online and produces KAP files for use offline in OpenCPN. Perfect as an extra aid to navigation in poorly charted areas, as described in my 2012 post here.
All the imagery I have created and which I have collected from others is intended to be shared. I have shared on an individual basis so far. The data is now available online.
The library is on Dropbox here.
For those who return to the library looking for new or updated information: click on the "Modified" column heading in Dropbox. This will sort the files by modification date with most recent at the top.
First download and store somewhere safe the file "_readmefirst.txt". Keep it for offline use. The contents of the file are below since it provides much of what I need to explain here. Please read on!
A Guide to using
Zen Again's Dropbox KAP File Library
for use with OpenCPN and SEAiq
Origin and Further Distribution
The KAP files in this library have been generated by various cruisers
including myself. All who have provided files to me have indicated their
willingness for me to distribute them further. The only proviso we make is
that they be further freely shared to assist other cruisers.
The KAP files have been tested in OpenCPN and SEAiq using the latest versions
available at the above date.
The ZIP files are named in the following formats:
A. <Region>_<Country>_<Locality>.zip or
The KAP files are split into modest size ZIP files for two reasons:
1. To allow the selection of specific KAPs of interest without having to
download large files.
2. To allow for use in SEAiq which (since it runs on tablets) could be
slowed dramatically if many hundreds of KAPs are loaded.
For those with pre-existing OpenCPN chart folders such as:
MacOSX: /user/Shared/charts/opencpn/ge/<region> or
Windows: /Users/Public/charts/opencpn/ge/<region> where region is Asia, Indian etc
simply add to (or replace) the existing contents with the contents of the
ZIP files you download here.
For those with pre-existing SEAiq chart ZIP files simply add my zip files
nearby and use iTunes to add them to (or later delete them from) SEAiq.
Using KAP Files
See the following blog posts:
Using GoogleEarth Imagery for Marine Navigation
Making KAP Files
GoogleEarth Imagery on iPad
GoogleEarth Imagery on Raspberry Pi
The library will be updated from time to time. Individual files may be updated
so check the date stamp of files you use. New files may be added so check for
new files in your region of interest.
If you would like me to add your images to this library just let me know.
GoogleEarth images FADE TO BLACK a few hundred metres from land!!!
Now to add some help for installing charts in OpenCPN and SEAiq.
Installing and Configuring in OpenCPN
- Download all the ZIP files of interest from Dropbox - usually to your downloads folder.
- Identify where your existing charts are located (Shown in OpenCPN in Options => Charts => Chart Files. [I locate my KAP charts in /Users/Public/charts/opencpn/ge on Windows and /Users/Shared/charts/opencpn/ge on Mac OS X]
- If they don't already exist, create folders for regions (eg SEAsia, Australia, IndianOcean or similar) in the folder you intend to use for your GE imagery.
- Unzip (on Windows use right-mouse-button => Extract To) each of the downloaded ZIP files to the appropriate region folder. Unzipping will create a folder for the <Locality> described in the readme file above.
- Check that your folder structure looks something like "charts/opencpn/ge/Australia/Abrohlos" with .kap files in the Abrohlos folders.
- If you wish you can add an extra layer of folders to fully mimic the file naming structure in the readme. This depends on how you wish to use Chart Groups - read on!
- In OpenCPN go to Options => Charts => Chart Files.
- You should see a list of chart folders OpenCPN is using, often including a folder "CM93". If you have some KAP files already loaded then there should be another folder.
- Click the Add Directory button, browse to the folder where your new KAP files exist, highlight the folder then click on Open. I suggest highlighting the region folder (eg Australia, SEAsia etc), not the locality folder (unless you want a Chart Group for each locality).
- Tick the "Force Full Database Rebuild" switch and click OK. OpenCPN will then scan all your chart directories building its chart index database, which may take a minute or three.
- When the rebuild finishes, zoom way out (using the "-" key) so you can see the regions covered by your GE imagery. You should see small red boxes which show the location of each image. If not go into Options => Display, turn on Show Chart Outlines, click OK and look again.
- To view a GE image zoom in over one of the red boxes and centre it in the screen. At the bottom of the OpenCPN window you should see blue "tabs" appear to the left of the yellow tab which was there before. The rightmost tab is always the real (vector) chart. Others are image (raster) charts. Click on the leftmost tab to open what is usually the best image for the location.
- Sometimes OpenCPN zooms when you change from one "tab" to another. IMHO this is a bug.
Configuring Chart Groups in OpenCPN
- Go to Options => Charts => Chart Groups. In the Chart Groups panel you will see an All Charts tab. We are going to add more so that the number of GE images OpenCPN is dealing with can be controlled despite them all being installed. I usually define Chart Groups for a region of the globe (SEAsia, Australia etc).
- To create a Chart Group click on New Group and give it a name (for example GEseasia) and click OK. Then click on your vector charts (often CM93) folder and click Add. Click on the relevant GE chart folder and click Add. You may wish to create a Chart Group called CM93only with no GE folders included.
- When finished click OK to exit Options.
- In OpenCPN zoom way out (using the "-" key) so you can see the regions covered by your GE imagery. You should see small red boxes which show the location of each image.
- Right mouse button, move over to Chart Groups and right into the list of groups. All Chart Groups is probably ticked. Click over another group and you should see a set of red boxes disappear. Chart Groups are a nice way to manage what images are accessible. Once familiar with all this you can turn off Show Chart Outlines since drawing them seems to keep OpenCPN quite busy.
- Download all the ZIP files of interest from Dropbox to the computer you use to sync your iPad - usually to your downloads folder.
- Identify where your existing charts are located. [I locate my KAP charts in /Users/Public/charts/opencpn/zip on Windows and /Users/Shared/charts/opencpn/zip on Mac OS X].
- Connect your iPad to the computer and let it sync if it wishes. Open iTunes if it doesn't open automatically.
- Click on the iPad symbol at top left of iTunes, then click on Apps on the left.
- Scroll all the way down past the Apps list to the File Sharing list.
- Click on SEAiq Open in the File Sharing list on the left.
- On the right you now have a SEAiq Open Documents list which may be empty. At the bottom of the list click on Add. Browse to the folder containing the downloaded ZIP files. Select those you wish to install in SEAiq and click Add. You will see a progress bar at the top of iTunes.
- On the iPad open SEAiq and click on Charts at bottom right. Wait for it - the response can take a few seconds if you downloaded ZIP files containing hundreds of images.
- When the Charts page loads you should see a row for each ZIP file, with each showing its size and number of KAP (image) files it contains.
- Now you see the logic behind the file naming scheme!
- Note that you download CM93 charts in a similar way, just select your CM93 ZIP file in iTunes and Add it to SEAiq.
- Click on Navigate and pan/zoom to the locality of the imagery you transferred. You should see faint orange boxes delimiting the images.
- To change between vector (CM93) and raster (KAP image) charts click on the Settings tab and and move the slider on the Raster line in the Charts section, then return to Navigate. You may need to pan slightly to have the page redraw. Hey Presto!
- ZIP files can be removed from SEAiq in either iTunes or on the iPad directly in the Charts page.
Here are two screenshots from SEAiq showing Cape Vlamingh on Rottnest Island WA. Breaks on the reefs are clearly visible.
|Chart (decluttered) of Cape Vlamingh, Rottnest Island, WA in SEAiq|