Hi,

working with a RC surveyboat and a HDS5 we face the following issue
after importing GPS sonar .sl2 file, the displayed sonar points are based on a interval.

is they interval based on time?? what is the interval by default??

would be very usefull to add different import intervals for different projects

it is possible for .csv import!


regards

Chris Berends

Hi Chris,
We import what is in the file - essentially we make a new data point when we get a new position in the sonar log. Position resolution in SL2 files is limited to (approx) 1m, so it won't be possible to get a higher point density than this.
Are you looking for more or less points?

Hi Matt,thanks for your reply

more points would be very usefull

if I use the lowrance sonar viewer 2.1.2 it gives me 19431 soundings and the number of points imported from the sl2 file is 619
so a sl2 file is 1 point per 35 pings?? the attached screenshot gives an overview of the used points during import as you can see it is not a regular interval

is the .sl2 data the peaksv pung or E1 or E2, is there any software setting to use E1 directly to avoid any discussion during the presentation.

regards chris

There is no strict "points per ping" - it depends a lot on how fast you are moving. The maximum point density is 1 point per metre (more or less), so files recorded at a slower speed will have fewer points-per-ping than those recorded at a higher speed.

I'm not sure of the merits of > 1 data point per m2. Firstly we couldn't take those values directly from the file - we would need to interpolate depths and positions from adjacent data points - this wouldn't really give us any more information, and this already effectively happens during the map generation process. Since RM bins data in a 1m grid during the map gen process anyway, I don't see an advantage to having a higher initial data density than this.

I'm not sure what you mean by your last question?

hi Matt,

a workflow ( from my point of view) could be.....

sonar file import (or direct access on tablet pc) sl2 file...i guess this is peaksv??
define E1 settings and add those settings to the project.
define E2 settings and add those settings to the project.

volume calculation based on the difference between E1 and E2

export different x,y,E1(elevation) of x,y,E2 (elevation) to a csv file for additional work in different software like AutoCad
combination of manual GPS survey data to make a complete (survey) surface or cross sections


regards

chris