Hi,

The histograms can be found in the (project and tracks) edit tab->Bottom Classification. I do not use any offset, but it might be needed for your hardware combo.

What I did to find my scale/offset value was to open Reefmasters rmdb-file in an SQLite database viewer (Mozilla Firefox has one), exported the table hardness_points (make sure to keep exports of different hardware profiles separated so you don't mix data) and made a lot of calculations on that data in Excel. A good way to see the characteristics of the data is to use histograms (available in Excel as well).

Regards,

/Martin

Nicely done! But is there a way that I could "see" from the histograms in RM what scale and offset I should set. Can they at least point me in some way in which direction I should start changing and trying different scales and offsets?

Hi,


I'm not at a PC with RM right now, but you set the scale and offset in the hardware profiles. When importing you choose what profile to use, I don't think you can change that after import - needs to be done while importing.

You can then view the histogram in the Edit->Bottom comp.

By looking at the present histogram for the SLG-files and comparing with the SL2-histograms you can make a guess what to set the scale-value to. Change the profile and reimport the SLG-files and make a new guess. This part is much easier to do in excel, but gettting the hardness data to excel is a bit of work...

/Martin

Hi Martin,

I have tried to change scale and offset and it can be done after import :) so it is much easier to change them and compare the results. I did that visually by looking at sl2 and slg tracks in project. However, it says in the RM manual that these histograms can help during comparing process and I didn't figure out yet how :( If anybody has a hint I would be grateful.

Ideally the histograms for a group of SLG-files should look similar to a group of SL2-files. To compare within RM I think you need to save screenshots to compare with. Make sure to sample enough data to get representative histograms.

The max-value should be about the same, and main bulk of values in about the same range. In my case it was enough to change scale-value to accomplish this.

Hi everybody!

Just as I thought I was getting somewhere with this, it got more complicated. In one project I have set, as I wrote, scale 0.5 and offset -3 and it looked good. The "problem" came out when I tried to apply these values in another project. However, in this other project, tracks recorded as slg look about the same as the ones recorded as sl2 and they seem not to need any correction ??? It seems that at the end I should just look that no track looks too different from others and correct it if I have to? Does anybody else have similar experience?

If you look at each track I think it will be difficult, unless they cover the same area or atleast an area with the same hardness.

I bunched together lots of SLG-tracks and looked at their combined histogram (project histogram), then the same for lots of SL2-tracks. If you have lots of data the histograms should give the true picture but if you only look at one track it is important what area that track covered.

Also, not only SLG/SL2 is important to treat differentlt - the hardware used is also important to know, specially transducer.

Thanks Martin!
It seems that it's really hard to get this all working well with the old data too:( But, for the new data it will all be great :)

True. I had some really old data logged with LMS-units with various transducers. I only use that data for depth mapping, it isn't included in my hardness-project. It would take too much work to get it correct and I don't always know what hardware was used.

If you area serious about hardness mapping I would recommend having a separate project for hardness. You typically want smaller interpolation for hardness than for depth, there are probably other settings too that might differ.

I use BC for fishing. I am trying to get it as good as possible. I was thinking about having separate maps but now I think it would be too complicated. I have a large area covered by old slg files and on different equipment and have no intention to go around again. I will just get this working the best I can and hopefully it will be good enough:)
Thanks Martin for all the advices!

I also use BC for fishing. Even though I keep depth and hardness in different projects (workspaces even) I mix their shapefiles together to the same map/at5 from within IMC.

But I also have some lakes mapped with logs mixed up from different hardware/file types and while not perfect it is better than nothing, the really hard places stand out anyway.

was this issue ever resolved............
the thread seems to go off on another issue
i too have issues with BC not showing up after editing a HB R0001 file ?
ds