Author Topic: SI -Range Lines  (Read 1118 times)

0 Members and 1 Guest are viewing this topic.

Offline RonnieB

  • RonnieB
  • Jr. Member
  • **
  • Joined: Apr 2015
  • location: South MS
  • Posts: 80
  • Unit(s): ONIX10CISI, XNT-1420T,360
  • Software: 2.0
  • Accessories: Ethernet, MinnKota Ulterra,Talon
SI -Range Lines
« on: May 13, 2015, 08:52:00 PM »
Probably dumb question, but I have lots to learn. When I am looking at SI, with it showing the water column, the range lines start at center line of the water column. To the first 10ft increment range line is including 1/2 of the water column.  So if am I looking at something 100 ft away, is it actually 90? Another way of stating it is: there is 20ft of water column on the map. 10ft on each side of center line. The first 10 ft is actually water column and not horizontal distance. If I took a paper map of it and pinched it together in center, the 10ft line would be actually be "0" or center.  :-[


Offline rnvinc

  • Hero Member
  • *****
  • Joined: Nov 2009
  • location: Western KY
  • Posts: 3127
  • Unit(s): 1197c SI Combo, Onix 8ci SI Combo
  • Software: Dependent on whim
  • Accessories: AS GRHA, AS GPS HS, LowBird LSS 1 & 2
Re: SI -Range Lines
« Reply #1 on: May 13, 2015, 08:59:27 PM »
The SI Range lines should be used a general guide and not definite distances to anything ...

Slant Range factors makes this difficult ...

http://forums.sideimagingsoft.com/index.php?topic=946.0
-------

The SI image shows a left and right water column because there is a left and right SI beam ...

The point where the water column meets the bottom detail is equal to the water depth ...



Any target echo that is closer to the xducer than the water depth will show in the water column of the SI image ...

Any target echo that is farther from the xducer than the water depth will show against the bottom detail ...

*The center line in the SI image is the xducer ...
*The left water column is what the left SI beam "sees" between the xducer and the bottom ...
*The right water column is what the right SI beam "sees" between the xducer and the bottom ...

Rickie
« Last Edit: May 13, 2015, 09:12:21 PM by rnvinc »

Offline RonnieB

  • RonnieB
  • Jr. Member
  • **
  • Joined: Apr 2015
  • location: South MS
  • Posts: 80
  • Unit(s): ONIX10CISI, XNT-1420T,360
  • Software: 2.0
  • Accessories: Ethernet, MinnKota Ulterra,Talon
Re: SI -Range Lines
« Reply #2 on: May 13, 2015, 09:30:57 PM »
to my rescue again rnvinc! Thanks.  I actually had saved that image and that article.    I didn't catch that though.  Slant range is a very deep subject. :-\

Offline caskey_b

  • Jr. Member
  • **
  • Joined: Feb 2015
  • location: Oxford, IA
  • Posts: 45
Re: SI -Range Lines
« Reply #3 on: May 14, 2015, 07:25:57 PM »
SI range lines do not factor in depth... so if you are in 10 ft of water, and your first range line reads 10ft, that is actually the ZERO mark, right under the boat...

but as mentioned above... angles play a huge factor in determining suspending fish... however, you can be fairly accurate with distance with bottom objects if you factor in the water column..

I run my SI without range lines... I feel as if they clutter up my screen... I usually fish between 50-75ft ranges so if I want to cast to something, I just quickly guestimate the distance...

Offline rnvinc

  • Hero Member
  • *****
  • Joined: Nov 2009
  • location: Western KY
  • Posts: 3127
  • Unit(s): 1197c SI Combo, Onix 8ci SI Combo
  • Software: Dependent on whim
  • Accessories: AS GRHA, AS GPS HS, LowBird LSS 1 & 2
Re: SI -Range Lines
« Reply #4 on: May 14, 2015, 09:02:13 PM »
to my rescue again rnvinc! Thanks.  I actually had saved that image and that article.    I didn't catch that though.  Slant range is a very deep subject. :-\


The difficulty is Slant range estimation is taking into account the compression factor involved in the SI image processing ...

Contour Mode actually gives a better scenario for estimating distances to outbound objects due to the lack of compression of the 1st few feet of bottom detail ...



Notice how the 1st few feet of the bottom detail away from the water column is compressed to allow room for the water column in the SI image ...

Rickie



Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo

 

Related Topics

  Subject / Started by Replies Last post
1 Replies
7333 Views
Last post March 25, 2010, 01:57:14 PM
by RGecy
3 Replies
1840 Views
Last post July 12, 2010, 10:47:34 AM
by RGecy
1 Replies
1468 Views
Last post March 25, 2011, 09:59:24 PM
by RGecy
7 Replies
1898 Views
Last post March 04, 2012, 06:25:28 PM
by newkid4si
6 Replies
1877 Views
Last post July 03, 2012, 06:41:27 PM
by bomac
20 Replies
8999 Views
Last post January 20, 2013, 12:28:26 AM
by mike fish
2 Replies
1294 Views
Last post April 29, 2013, 11:11:31 AM
by Humminbird_Greg
4 Replies
1081 Views
Last post April 05, 2014, 09:17:20 AM
by LittleGazoo


SimplePortal 2.3.3 © 2008-2010, SimplePortal