Can Sight 'n Go do this?

[darford]

Today when I was driving I could see a lot of smoke in the distance (it turned out to be a large brush fire) and I had a thought...

 

If I had a GPSr with a compass and it could project two projection lines, then I could sight on the smoke, move a distance and sight again with a new bearing. If the map would show these projection lines on the screen, where they cross should be where the smoke is. More projections would just improve accuracy.

 

I could imagine a few uses for a feature like this.

 

I have a Meridian Gold and I know the Platinum can't do this, but how about some of the Garmin models?

 

Waddya think?

[+park2]

I have a Vista that can sight n go but it only sights to a point (at x distance along bearing y line), it doesn't leave a sight line. When you move, the original line won't be there.

[+Alan2]

I think a Vista could do it as follows. Mark a waypoint where you are currently. Using "sight 'n go", sight the fire and mark a waypoint way past the fire let's say 10 miles away. You now have two waypoints with an invisible line crossing the fire.

 

Now move your location and repeat the process. Download the 4 waypoints onto Mapsource on you pc. Draw a route for each pair of waypoints. where they cross, mark the fifth waypoint which will be where the fire is located.

 

Does this work for you?

Alan

[darford]

Alan,

 

Your suggestion would also work on my Meridian Gold. Without the compass, I would have to move in the direction of the smoke a short way to get a heading (bearing) for it, then I can project a waypoint way beyond it. If I had my Brunton compass with me I wouldn't need to move.

 

Do the same for a second sighting and download to Mapsend or TOPO!.

 

Thanks for the suggestion.

[jfitzpat]

quote:

---

Originally posted by darford:

Alan,

 

Your suggestion would also work on my Meridian Gold. Without the compass, I would have to move in the direction of the smoke a short way to get a heading (bearing) for it, then I can project a waypoint way beyond it. If I had my Brunton compass with me I wouldn't need to move.

 

Do the same for a second sighting and download to Mapsend or TOPO!.

 

Thanks for the suggestion.

---

 

But a compass, built in or external, will generally be more accurate. Remember that most GPSr's infer bearing based on positional shift. A slight change in unit orientation or body position can easily create an error of 20 degrees or more (there was a good article on this in a magazine recently, but I can't find it here at the moment - I'll try to dig it up).

 

-jjf

[+phantom4099]

Why download to mapsend, or mapsource when you can create a route on the GPS? I was thinking(I did not read the other log too in depth) mark(1) your current position then project a point past the fire(2). Move down the road and mark position again(3) then again past the fire(4). Make a route with 2 first, then 1,3, and 4. Activate route and zoom in where thay cross and mark that point(5).

 

Wyatt W.

 

The probability of someone watching you is directly proportional to the stupidity of your actions.

[Alphawolf]

Just watch the news tonight and they will tell you where the fire was! ;-)

 

[+Olar]

You've all given me an idea of how a cacher must find a new cache. I've wanted for some time now to come up with one that depended on accurate compass techniques in conjunction with our GPSRs. I suppose it would fall under the category of an offset cache but utilizing the triangulation aspect of navigating. Back to the drawing board with my imagination.

Cheers, Olar

 

[+Jamie Z]

Olar... I just had a thought...

 

What if you provided a small map of the area for the cacher to draw the triagulation on. Put a handfull of them in a cache along with the directions.

 

Each cacher takes one map and uses it for triangulation to the final cache.

 

Jamie

[jfitzpat]

quote:

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Originally posted by phantom4099:

mark(1) your current position then project a point past the fire(2). Move down the road and mark position again(3) then again past the fire

---

 

Unless I'm missing something, it seems like you would still want a compass of some kind to determine the bearing to project each waypoint.

 

-jjf

[+phantom4099]

Yes you would need a compass of some type. I tried this on a small scale with my merigold and a lenstatic compass. i was able to get within 4ft of my target, the error will probaly be larger the further away you get. In which case more readings may help (2,1,3,4,3,6,7).

 

uh yeah the magellan unit allow you to project from a position other than you current position (like old waypoints, or any thing else in the database)

 

Wyatt W.

 

The probability of someone watching you is directly proportional to the stupidity of your actions.

[+Jamie Z]

A bit off-topic, but regarding the Meridian projection feature.

 

I did a projection a couple weeks ago. I went the the site and could not find the cache. Thinking maybe I'd made an error, I did the projection again... and the resultant coords were slightly different the second time.

 

I'm almost positive I used exactly the same information for the projections, so I was confused why there was a difference. Isn't it some mathematical formula to calculate the projection? The math should be identical. Granted, this projection was for 17 miles, but it should be the same for any distance, I would think.

 

Jamie

[+apersson850]

quote:

---

Originally posted by Jamie Z:

I did a projection a couple weeks ago. I went the the site and could not find the cache. Thinking maybe I'd made an error, I did the projection again... and the resultant coords were slightly different the second time.

 

Jamie

---

 

And you are certain that your starting coordinates were identical? Remember that the unit uses more decimals than it shows to you, and rounding may cause a result that differs visibly at the other end of the line.

 

When projecting with a Vista, without telling it how far to go, it creates an imaginary waypoint 30 nautical miles away.

They obviously did this to be able to handle such a GoTo just as any other, and also to prevent the bearing line to come back and hit you in your neck, when it had gone around the globe once.

 

Anders

[+Jamie Z]

Anders,

 

I'm not certain, but I'm pretty sure about it.

 

The first leg of the multi told me to project a waypoint from the first cache. So, when I went into the "project" function, I projected my new waypoint straight from the cache waypoint that was loaded from EasyGPS.

 

I have a Meridian Gold. It then asks for the direction (in degrees) which I entered to the nearest degree... and then the distance, which I entered to 0.01 mile. The two projected waypoints were different by about 100 feet or so.

 

Anyway, I think it's too likely that I mussed something up, so rather than fret about why the GPS is giving inconsistant answers, I ought to go out and scientifically project two waypoints from the same coords and see if the results are identical.

 

Jamie

 

(By the way, Anders... you never answered my question in this thread.)

[+phantom4099]

I know you probaly know better than this, but it is my only idea. Are you using a magnetic compass but have the merigold set to true north?

 

Wyatt W.

 

The probability of someone watching you is directly proportional to the stupidity of your actions.