Setting "Map Offset" on HB units....

**Humminbird_Greg** · 03-23-2011, 12:36 PM

“How does one accurately check if their unit even needs the "Map Offset"...??”
About the only way to do this is if you observe that your boat’s position is shown in one location yet some fixed structure is shown in another. The example of the bridge is a good one to use as these usually don’t move around a lot.

“How does one then use this feature to adjust their map accurately...??”
I think that Eddie did a good job of explaining this.

“If I have waypoints saved in my unit that were saved while the map was possibly off...will my saved waypoints be inaccurate after setting the "Map Offset"...??”
No they will not as the coordinates will be the same. They will appear in a different location on the map though. Think of it this way: the map is just a background picture that can be moved around. Setting the Map Offset feature effectively moves the background map around. It does not change the coordinates of your waypoints.

One thing that was not mentioned is that on some of the lakes and rivers on the mapping cards we think of these as a single big map. They are not always one map and can be several combined together. This means that the map offset may not be needed on all areas of a lake and setting it for one area of the lake may make it off on another.

**Cane Pole** · 03-23-2011, 12:40 PM

Hey Greg, with only one waypoint required, how do you know which way to "rotate" the map? I like this feature, but it didn't help me out any.

**Humminbird_Greg** · 03-23-2011, 01:02 PM

We don’t rotate the map CP. It is just a simple Lat/Lon adjustment. If the maps are rotated it will only work to improve the accuracy in the spot you offset it at.

**Cane Pole** · 03-23-2011, 02:48 PM

The pylon is about 5 miles up stream from where I was expecting some correction. Was this too far a distance from where I was expecting some correction? Book didn't give much info. I can go try a recalibrate. I verified my calibrate waypoint with Google Earth. Pretty accurate.

**talltimber** · 03-23-2011, 03:55 PM

With no rotation, I would expect the farther you get from your control point, the less accurate the map will be.

CP, did your map show you were right on your spot before you calibrated, or could you see a little difference there? (your boat icon I mean)

**Cane Pole** · 03-23-2011, 04:38 PM

I had a donut. I was tied off at the pylon, so I wasn't moving anywhere. Been a while(bout 2 years) so I don't remember the details. I like the feature, but maybe I was expecting too much.

I marked the waypoint and calibrated the map while tied off. You don't have to be on the spot to calibrate using the cursor.

**Cane Pole** · 03-23-2011, 04:39 PM

Has anyone else tried the Map Offset besides me??????????

**rnvinc** · 03-24-2011, 07:32 AM

I'm still trying to find a good activation spot close to where I normally fish so that I can check my map to see if it even needs calibrating.

Rickie

**Cane Pole** · 03-24-2011, 08:27 AM

Maybe Greg Humminbird will give us a "effective" distance the calibrate will affect. I may have been too far away from the calibrate point. This is not documented. I verified my point by going to Google and uploaded my waypoint. It was right there by the pylon where I marked it. Did this just to verify my mark.

**Humminbird_Greg** · 03-24-2011, 01:31 PM

CP,
It is my understanding (and what I have done) that you have to be on the spot that you are using to ‘calibrate’ or use the Map Offset feature. Not being on the same exact spot would through the offset off a bit. I’ve always used a boat ramp myself.

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