Jumat, 23 September 2011

Indonesian Bathymetric layer in IMG format

Dear Prienz,

After searching for free bathymetry data for Indonesia, it seems that the multibeam bathymetric data is the best free data source, but unfortunately it does not cover the whole Indonesia. From all free sources, the easiest way is to download it from GEBCO (General Bathymetric Chart of the Ocean), they provide the data of world bathymetry for free. You can download it from here, but you are required to be a registered BODC web user, don't worry, its free.

I use the 'The GEBCO_08 Grid' (30 arc-second) and process it into *.IMG format. This 30arc second ocean depth data is not as good as the aster gdem land altitude data. So, dont be surprised if the beach line is not really accurate.The original data from GEBCO is shown below:
Original data from GEBCO
The theory that Indonesian islands, millions of years ago, used to be part(joined) of two continents could be true, you can see from the color of ocean depth. During ice age, possibly we could walk to neighboring countries. The theory can then continue and become more and more interesting.

Anyway, the final results are a bunch of IMG files which cover the area as shown above, divided into 1250 tiles. Each tile size is about 2MB, which can be combined with other maps, installed to Mapsource or Basecamp to see the ocean floor. Transfer the map to your device as usual through Mapsource or Basecamp.

Using Mapsource, your map will look like this:
Navigasi.net map with bathymetry data.

Using Basecamp, the ocean depth data is available, as shown below:
Navigasi.net map with ocean depth, just realize ocean depth can reach more than 4km.

Too bad, although these files are possible to combined with bluechart map for Homeport, but unfortunately, ocean depth is not shown in the depth profile tab (maps are shown in homeport). I do not know what went wrong (probably caused by the cgpsmapper process), but if you can find a way to make it work with Homeport, please post it here.

The Layout of the IMG files is shown below, the numbers represent the last four digit of the files. I use excel to make it easier for me.
layout in pdf format is also available here.
the layout legend shows the files' names to download. All files are available for free download at here.

You can use Gmaptool or Mapsettoolkit for combining the tiles with other maps.
  • For creating a marine map for homeport, use gmaptool but you have to check the 'Create TDB for Marine map' option.
  • And if it is needed (when overlapping with other maps), you can also use gmaptool to make these tiles transparant by modifying the 'Set transparency' option.
  • when only using gmaptool, try to check the 'add empty DEM' option.
'set transparency' option in gmaptool
'Create TDB for Marine map' option in gmaptool

If you have a garmin device that able to use G2vision map, please try these files and please post the result here. It might be useful for me or others.

well guys, enjoy. hope it is useful for you.

Sabtu, 26 Maret 2011

Update --- DEM Layer for Indonesia Country

To be used with Mapsource, Basecamp, and garmin units that supports 3d map.

This new version is actually the same as the previous one. the difference is that the new one consisted of smaller tiles, which will reduce the burden for slower computer. Although these have not been tested yet, but I think it should also reduce the burden for your garmin units.

If your computer/garmin unit does not have problem with the previous version, there is no need to download the new one.

With Basecamp 3.1.3, combination (either the previous or new version) with navigasi.net map can be seen in 3D.

The new DEM layer consisted of more than 600 tiles, and this is the layout:

Use this layout for choosing the tiles that you need. Open the image in a separate browser tab, it will make you easier to read the small numbers. These numbers represent the last three digit of file names.

I'm still uploading these 608 tiles, so, please be patient. Whenever the tiles are shown in the link, you can download it.

The tiles are available here.

Have Fun.

Senin, 01 November 2010

DEM IMG for Indonesia country

Searching the internet, found One guy who managed to create custom DEM files for garmin GPS. He said that the original DEM data came from ASTER, which provides it for free covering the whole world. ASTER GDEM data is available for download at http://www.gdem.aster.ersdac.or.jp/index.jsp

He processed and prepare IMGs contain DEM for Indonesia, ready for your Garmin GPS which support 3d map. These DEM IMGs covers the whole country of Indonesia, tested with GMPC, Colorado, and Oregon. Logically, other similar Garmin products should be able to use it also. 

At the beginning, there were 57 file DEM IMGs, but several areas were not correctly processed and 9 additional small tiles were needed. So, totally he prepared 66 file IMGs with total size 4.78GB, the biggest file size is 228MB.

Anyway, here is the layout of the DEM IMGs files:
 - B61 --> part of sector B6                                             - B71 --> part of sector B7
- C21 --> part of sector C2                                             - C41 --> part of sector C4
- C61 --> part of sector C6                                             - C81 --> part of sector C8
- D61 --> part of sector D6                                             - D91 --> part of sector D9
- E61 --> part of sector E6

Since the IMGs practically is a blank map, combination with other map (contains POIs, roads, etc) is needed. Use Gmaptool for combining the maps and installing to mapsource, then use mapsettoolkit for patching the TYP file (of the road map). Transfer the combined maps (both road map and DEM IMGs) to garmin device as usual from mapsource/basecamp.
Combination with Navigasi.net map will look like this:

Install only the DEM IMGs If you want to use the 'view 3d maps’ feature from Basecamp.It will looks like this:

You can combine your current road map with the DEM IMGs as one GMAPSUPP for your device. But it is also possible to use the DEM IMGs as GMAPBMAP and keep your current GMAPSUPP intact. Tested with GMPC and works fine.
He tested the merged gmapsupp in Colorado and Oregon, and here is the pic:

Do not use all 66 DEM IMGs in your garmin device, first is because Mapsoure only allows maximum 4GB for GMAPSUPP transfer, Second is because it will burden your device and create unnecessary delays.

The new files are available for free download, please read the new posting here.
Use the IMGs layout above for selecting which IMG you need and download.

have fun with it.