[postgis-users] Reading MaxSea PTZ file format

[Ragnar Johannesen]

I am currently working on a project, where I combine several MaxSea 3D
databases, which contain depth measurements made by the echosounder onboard
on a ship. The idea is to combine these databases to create a detailed
seafloor map around the Faroe Islands.

The file format is proprietary, and the files generated are named 3DDB.PTZ.
By inspecting the file, is see that it is a password protected Microsoft
Jet database, but with some tools, I have been able to read from the file.
The database contains a table named 3DTable which has the following
structure:


╔═══════╦══════════╦═══════════╦══════════════════╦═════════════════╦═════════════╦═══
═════════╗
    ║ Level ║   Lat    ║    Lon    ║ WeightDepth_CMap ║ ValueDepth_CMap ║
WeightDepth ║ ValueDepth ║

╠═══════╬══════════╬═══════════╬══════════════════╬═════════════════╬═════════════╬════════════╣
    ║     7 ║ 88021504 ║ 220475264 ║                  ║                 ║
        1 ║ -48.64608  ║
    ║     7 ║ 88021504 ║ 220475392 ║                  ║                 ║
        1 ║ -48.64608  ║
    ║     7 ║ 88021504 ║ 220508928 ║                  ║                 ║
        3 ║ -19.2024   ║
    ║     7 ║ 88021504 ║ 220509056 ║                  ║                 ║
        2 ║ -13.35024  ║
    ║     7 ║ 88021632 ║ 220474880 ║                  ║                 ║
        1 ║ -48.64608  ║
    ║     7 ║ 88021632 ║ 220475008 ║                  ║                 ║
        1 ║ -48.64608  ║
    ║     7 ║ 88021632 ║ 220475136 ║                  ║                 ║
        1 ║ -48.64608  ║
    ║     7 ║ 88021632 ║ 220509056 ║                  ║                 ║
        3 ║ -21.0312   ║
    ║     7 ║ 88021632 ║ 220509184 ║                  ║                 ║
        3 ║ -21.9456   ║
    ║     7 ║ 88021632 ║ 220509312 ║                  ║                 ║
        1 ║ -7.3152    ║
    ║     7 ║ 88021760 ║ 220461696 ║                  ║                 ║
        1 ║ -70.77456  ║
    ║     7 ║ 88021760 ║ 220474624 ║                  ║                 ║
        1 ║ -51.75504  ║
    ║     7 ║ 88021760 ║ 220474752 ║                  ║                 ║
        1 ║ -51.75504  ║
    ║     7 ║ 88021760 ║ 220509952 ║                  ║                 ║
        2 ║ -14.6304   ║
    ║     7 ║ 88021760 ║ 220510080 ║                  ║                 ║
        5 ║ -33.8328   ║
    ║     7 ║ 88021760 ║ 220510208 ║                  ║                 ║
        2 ║ -13.53312  ║

╚═══════╩══════════╩═══════════╩══════════════════╩═════════════════╩═════════════╩════════════╝

The column Level ranges from 5 to 21, in this particular dataset. However,
I do not know how to process the data, as I do not know what
format/projection the columns lat/lon is, and how to make sense of this.

In the project (it is my Bachelors project in Software Engineering), I will
focus on the data quality, and how I can combine different datasets from
ships and trawlers to create a detailed map. I have reference data from a
research ship belonging to the Faroese Marine Research Institute, taken
with a calibrated echo sounder of a higher quality.

To assist me in the process of combining the data, I intend to create a
open source `ptz2pgsql` utility, similar to the `shp2pgsql` utility, and I
would appreciate it, if someone of you could help me make sense of the data
I have available at hand. I am able to send a sample of the data to you (a
PTZ database). I have also contacted MaxSea to ask if it is legal to
reverse engineer their proprietary file format.

I am not sure if this is the correct place to ask this kind of question,
but I was pointed here from my question here
http://gis.stackexchange.com/questions/62362/importing-maxsea-3d-database-to-postgis.
However, I like to think that there are some users on this list with
interest in collaborative bathymetric data.



Thanks,
Ragnar Johannesen

Student at Fróðskaparsetur Føroya (setur.fo)
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