John,
I assume you are talking about changing the overall level of the finished map, rather than the levels of the individual tracks (which you can do using tide offsets).

There is no way to do this at the moment, but it would be a nice feature. We'll look into adding something, probably during the export, where a whole map can be moved up or down by a specified amount. For now, there's really not a lot I can recommend, unless you want to get your hands dirty playing with Shapefile exports. It would be possible, for example, to export a map as a set of shapefiles, open them in an application such as qGIS and adjust all the depth values using a simple formula; + or - a fixed offset.

Matt

Good Q John. My lakes here are the same way but we call it summer pool and winter pool...can be as much as 20 + feet.

Would be nice to be able to make an adjustment to the final map to add / subtract X FOW for the time your on the lake.

Matt wrote:
Hi Matt, A new feature to adjust the overall level (up or down) during export would be perfect.

Hello John,


what an interval is practicable and sufficient: +- 0,5 m, +- 1 m ..... +- 5 m or feet from the existing chart depth values (the simple way)?

In this case - is there a relevance to the flat shore region? Do You need the changed shoreline structure or only the deeper Areas (the difficult way)?


Bets wishes
fjordfisher

Hi fjordfisher, I'm not sure what you are asking?

I think Matt has my problem figured out. Using my example above this is how I see the process working

- for each lake have a "full" level depth. My example it is 361.67 m
- record a track and obtain the water level on the day. I'll use Feb 2014 - 347.46m
- when I import this track, I use the tide offset function to adjust the data to the Full level. (361.67-347.46=14.21) So would +14.21m to this track.
- Repeat this for all the tracks so they are adjusted to the "full" level
- Tomorrow I want to use a map on the lake and the level is 352.1m. So 361.67-352.1=9.57
- Using the new feature (not introduced yet) to adjust the overall water level when the map is produced then I would -9.57m, which would produce a map matching the current level.

I'm not sure how the map would display depths for areas that are between the defined map shoreline and the new virtual shoreline? Maybe it will just display as 0 or +xx depth contours? Or perhaps turn yellow to show as land?

I understand You an we only speak about data export. The solution, that You want is only possible, if You use an comoputer directly before You go to fish. In principle each new day - a new chart. I Think, Matt can create this solution.


But i would propose a practicable solution, that You can use changed depth without computer, only with the knowledge of water level, also if the depth change during fishing trip. There is an IMC option for such solution ...

I did have a look at the Humminbird AutoChart option, where I could adjust the depth on my Humminbird sounder directly - on the water.

The problem is that Humminbird has a limit of +/- 10m adjustment.

I looked at one of the lakes I use and it is currently just over 24m under level. So the depth change is outside what I could achieve using the sounder.

My proposal is only for Lowrance units, least idea from HB. In this case (HB), only Matt can help.

In principle there is no limit for depth changing with the IMC option, but the intervall should be practicable.

What is the IMC option?

It's an option in a beta - not yet for the public.
Time for change the depth values on the water - a few seconds.

If allowed (i must ask) i can create a fictive sample as illustration.

john wrote:
That is some massive changes in water level!! Just curious - are there boat ramps that works for all those levels - they must be massive as well!

/Martin

The ramps are way up the bank. There are heaps of places where the dried bank is firm gravel so you can back your boat down. Other places are soft mud and some people get bogged to the doors.