Google Earth ?

[cdennyb]

Earth Bridge - Bridge the gap between Google Earth and your GPS receiver.

THIS FREEWARE PROGRAM MAKES JUST ABOUT ANY (oops locked capKey) handheld GPS unit compatible with the new or old free version of Google Earth.
I goto the area I'm going to be traveling or sailing in and do a closeup view so the GE program will cache the data stream for viewing later on.Then when the time comes, I fire up the handheld and laptop and start EarthBridge and I'm tracking and laying down a pathway at th same time. It's pretty good accuracy and if used as a tool in the arsenal of preventing me from grounding then it's great. Use it with care and it'll bring home a bunch of ariel views you could'nt get otherwise of where you were, literally.

[LeeSailor]

I didn't read every word of this thread, but I browsed through it all quickly. I didn't see this site mentioned. Google Earth + NOAA Charts:

NOAA

[GordMay]

Originally Posted by LeeSailor

I didn't read every word of this thread, but I browsed through it all quickly. I didn't see this site mentioned. Google Earth + NOAA Charts:

NOAA

Really cool site, tho' (with all that data) a little slow loading.

[BeBalu]

I think the best use of google earth is simply to stare at it and dream...at least that's what I find myself doing a good portion of the day.

[Hud3]

This is a land-based example, but perhaps of interest.

A few friends here on Nevis have been using GE to plot our GPS waypoints from hiking expeditions. We're attempting to find new routes up to Nevis Peak (3232', 985 m), and to rehabilitate old trails that have fallen into disuse. It's a powerful tool, due to the realist visual representations you can achieve.

Here's an example in 3-D, below. BTW, I've found a fairly consistent error between GPS and GE here on Nevis. GE places our waypoints about 90-120 feet north of their actual locations.

[GS3]

Originally Posted by phiggins

One problem I found was measuring a bearing when making a path or line. I found a very useful compass tool that really helps:

Useful tools - Google Earth Community

If you make a chart from GE make sure you press the 'r' key to make the lat and lon lines parallel to the sides of the screen first.

Recent versions of GE provide the heading with the Ruler tool so this compass tool is unnecessary for obtaining headings but I found it can be useful for education and training so I modified it somewhat to make it a bit better, specially in reducing the unnecessarily large file size. I have posted it here.

[Pblais]

Here's an example in 3-D, below. BTW, I've found a fairly consistent error between GPS and GE here on Nevis. GE places our way points about 90-120 feet north of their actual locations.

That's the problem with GE they use a "pound to fit" method. When you do the whole world (not all of it) you don't get to make new images. It's almost all done with existing mags banged into position. The fact that it works at all is pretty cool. I worked on the patent for measuring with accuracy from images. We started with land based images and now do air as well. That method does things a lot more accurate since the camera lens is located in space to exceptional accuracy using ring laser gyro and GPS with differential correction. The GE images are just eye balled into place. The seamless browsing is the key feature that gives it the illusion of being more than it is.

GE has added oblique images as well. Yahoo is doing the same for urban areas. There is a company doing roofing estimates using it as well. They can measure the roof with amazing accuracy. That stuff is much better than GE quality. You can click two pints and measure distances.

[scotte]

Originally Posted by Pblais

The fact that it works at all is pretty cool.

This is a great quote, because it's so true. Even with errors and shortcomings, GoogleEarth is really pretty amazing when you get your head around what it's doing and the vast quantity of data you can get to within seconds.

[Cowboy Sailer]

You can click two pints and measure distances.

Yep, clicking pints is always good!

[Hud3]

I'd click a pint or two with any of you swabbies!

[phiggins]

Originally Posted by Hud3

This is a land-based example, but perhaps of interest.

A few friends here on Nevis have been using GE to plot our GPS waypoints from hiking expeditions. We're attempting to find new routes up to Nevis Peak (3232', 985 m), and to rehabilitate old trails that have fallen into disuse. It's a powerful tool, due to the realist visual representations you can achieve.

Here's an example in 3-D, below. BTW, I've found a fairly consistent error between GPS and GE here on Nevis. GE places our waypoints about 90-120 feet north of their actual locations.

Hud,

I assume you mean GE is off as compared to your GPS, right? Was the GPS using WAAS?

I just tried a test on my location: I put a GE placemark on the corner of my street and the took my Garmin Etrek with WAAS on and went to the corner and created a waypoint. The GPS said the accuracy was +-25 feet. When I compared the GE placemark to the waypoint, the latitude was dead on. The longitude was off by .001 minutes which is about 5 feet. Pretty good I think. It would be interesting to see what other people find making a similiar test.

GS3,

Recent versions of GE provide the heading with the Ruler tool so this compass tool is unnecessary for obtaining headings

Thanks, just before you reported that I noticed it and wondered if I hadn't noticed this before on the old version. But anyway that is good improvement, much easier to plot routes.

[Hud3]

Phiggins,

I took a waypoint on my verandah and entered the lat/lon into GE. The resultant point on GE was about 120' north of the aerial photo of my verandah. The GPS that I used is a Garmin GPS48 and not WAAS enabled. But one of the guys that I hike with has a WAAS handheld, and it looks like the trails that we've plotted with it are maybe 80-100' off, again to the north. I think the answer is what Paul said in his post, above. GE stitches the aerials together to visually fit. I imagine some areas of the globe fit better than others, thus your excellent accuracy results.

[Greenman]

Could someone one with a bit of experience have a look at this site please? It looks pretty interesting to me, but I am pretty short of know how ATM in the e-charts area. LOL I just learned all the different (Canadian) bouys last night, so chart reading is very new to me.

EarthNC - Nautical Data for a Digital World » Free 3D Charts & Maps

[Pblais]

Could someone one with a bit of experience have a look at this site please?

Part of the site is about getting a DVD of charts all of which you could download for free. The other part is the overlay software to impose the ENC vector data over google earth 3D. That would be the part they actually add value for. It looks great in the examples they show but it's not like the rest of the planet looks that good. We have a raod trip to Top Sail Island, NC coming up and I played with the new Google Earth 3D to check it out. It's OK but it really isn't better. Viewing charts in 3D I thinkmloses it's wow factor once you start using them. You get information overload pretty quick. It is a cool video game like experience though.

The new ENC charts are easier to read than the old raster charts.

[Exocet]

I use GE in the planning stage for a trip, not for navigation. I find GE usefull in spotting possible anchoages, slips or towns which may be of interest. Also with the measureing tool I can get a rough estimate of the distance between legs (surprisingly close). As far as trying to compare GPS co-ords with GE, not sure how that works. When converting distances on a map to distances on the ground you must correct for two scale distortions, 1:effects of map projection distortion, and 2: the geometric effect of your height above the refenced surface. These are only a few reasons why your GPS does not jive perfectly with GE.