User manual

SimradES70
Figure10Bottomslopes
(CD010217-002)
Example28Bottomslopes
Theedgeofthebeam(A)hitsthe
bottomrst,andstartstogivean
echo.Thebottomdetectorinthe
ES70measuresthestrongestecho,
detectswhatitthinksisthebottom,
andstartsthewhiteline.
Theareaabovethebottomdetection
(B)willbemaskedoff,andeven
thoughitmaycontainshthesewill
notbevisiblebecausetheechofrom
thebottomisstrongerthanthose
fromthesh.Theestimateddepth
(C)willbeshown.
OntheES70thephenomenonwill
causethebottomline(E)tobe
distorted.
Example29UsingtheBottomBackstepparameterforseagrassdetection
IfyouuseanOlexsystem,youcantakeadvantageoftheBottomBackstep
parametertodetectseagrass.Decreasethebottombackstepvalue(makeitmore
negative)sothatthebottomisdetectedatthetopofanareaofseagrass.TheOlex
willthendetecttherealbottom,andtheresultistheheightoftheseagrass.
→Adjustingthebottomdetectiontondseagrassonpage73
Example30UsingtheBottomBackstepparameterforatshdetection
Ifyoushforsole,ounderorsimilarspecies,youcanusetheBottomBackstep
parametertoenhancethedetectionofthesh.Increasethebottombackstepvalue
(makeitmorepositive)sothatthebottomisdetectedslightlydeeperthanthe
correctdepth.TheES70willthen“pushthrough”theshbetter,andtheatsh
willbeshownastheyarelocated“above”thebottom.
→Adjustingthebottomdetectiontondatshonpage72
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