Would this be normal ?

I mean, i put the Interpolation on 50 meters and I would think that I have pretty good sonar coverage and data, but that does not seems to be enough. Why does this software make this gaps ?

Looks reasonable to me with a 50m interpolation. The gaps between the tracks look significantly larger than 50m for most of that map? Bear in mind that RM does not extrapolate at all, so for a straight track that is > interpolation distance away from any other data, the only points that will be within interpolation range will be along that straight line - hence the straight areas of very thin "map" and large gaps. Those gaps will go with a high enough interpolation setting, if you want them to.

Ok so I would like to go over the area much better and maybe over some twice to get it good enough coverage without putting the interpolation to high. If I set the interpolation to high you will get errors or not very accurate map, right ?

@DiveExplorer

I started out with maps like yours. I put the map back into my GPS and deliberately tried to fill in the gaps on my next visit to the area. I'm now down to using 25m and I'm still getting gaps (a lot smaller now). A side benefit is that I have "found" a lot more interesting places to investigate further. My use is mainly for fishing so I'm looking for reefs and other structure. Have to say Reefmaster has changed the way I fish...

i had a few 25m gaps in my survey area and used my plotter to define areas that needed going over, but next time I'm going to try taking a laptop out with RM on (I have wired in a 9 pin d-sub connector to the nmea 0183 output from my Lowrance unit - not difficult to do, just needs a very cheap 9-pin connector, a soldering iron and a usb to d-sub connector for your laptop). Will then run RM in live mode keeping an eye on the project contour map (which i think should update as you go), to try and get the area covered with no gaps.

Incidentally, Matt, a useful add on to RM might be an automatic survey planner - i.e. you put in a coastline / islands into the software, the maximum interpolation value you require, whether you want a 'box' or parallel line survey (and on which heading), start and end points, turning radius etc and RM works out track lines for you to follow on the RM projects display. WP's could also be exported within the work area to put on your GPS. Guess it would be quite a bit of work and I'm not sure everyone would want / need it, but id be very interested :-)

Hello hermes,


such a automatic survey planner is a great ides. I propose for this:

- tolerance range (as area)
- angle definition for line directions

(For SS Mosaik there is the additional problem of dependence from the depth - not solvable without known depth)


Here is a sketch to it.




Best wishes
fjordfisher

I think it could be a nice idea, but there are practical (and liability related) issues that I can think of.
Perhaps a relatively simple function to create parallel tracks like you have shown, Fjordfisher. That could work, but it would be hard to create something that respected the shoreline, or indeed shallow areas that shouldn't be navigated.

Maybe a simple option that lets you specify (draw with the mouse, perhaps) a rectangle and then populates the rectangle with parallel lines (angle and spacing could be specified). These could then be exported as tracks (for HB) or in an AT5 map. Repeating the procedure using orthogonal angles would give you two sets of parallel lines that form a grid.

Presupposition mus be, that the user self draw a shore line and circles around lslands, flat & dangerous Areas. The rest could create the program as suggestion with warning notices: don't travel on flat Areas, use flat alarms, ....

Thanks for the information and input.

Next thing I am working on is similar to what hermes is doing. But I will be using Pocket Pc with Dr.depth software and NMEA via bluetooth. Then maybe I will be making maps with less gaps and lower interpolation.