Amazingly detailed aerial photos on a GPS

I've been playing with a DeLorme Earthmate GPS PN-20 for the past few weeks, and have been pretty impressed with it overall. I've updated my PN-20 review, adding lots of screenshots and observations, so I wanted to point that out.  But one thing just blew my mind yesterday.

The image on the left below shows the PN-20 on a very faint grass path. You can actually see the trail on the aerial photo on the GPS screen. I had just arrived there when I took the screen capture below on the right. The trail is just to the left of the position indicator. It's faint enough that I might not have even seen it had it not been for the GPS.

Wow. That's really impressive. Now the trail could have been bigger when the one meter/pixel aerial photo was shot. In general though, it's not that unusual to be able to pick out things like desert tracks or anything  that changes the light reflectivity of the earth's surface. The PN-20 isn't the be all and end all, but the aerial photos are a very cool feature.  For the rest of the story, read my full DeLorme Earthmate GPS PN-20 review.

Comments

[Helpneeded]

Hi
I was wondering if you know of an algorithm or code to convert from GPS seconds to UTC time. Any help would be appreciated.

Thanx

[Rich Owings]

I don't, but I would suggest asking at one of these two forums, which seem to have broad readership including folks who are technically inclined...

http://forums.groundspeak.com/GC/index.php?showforum=11

http://tech.groups.yahoo.com/group/map_authors/

HTH

[bob]

good day, I am in need of a gps for checking on timber land in Maine, I will be on foot or atv and need ease of operation and the ability to mark waypoints along with a topo map. a large color screen would be nice too, I do not see any info on ease of operation in your comparisons, can you help? thanks

[Rich Owings]

Bob,

In general, Garmin has a more intuitive interface than other brands. For ease of use, I like the button layout on the 60CSx more than the eTrex series. One caveat...Magellan is getting ready to introduce the Triton series, which can show better quality topo maps. http://gpstracklog.typepad.com/gps_tracklog/2007/08/more-on-the-mag.html Whether or not they nail the interface is something we'll have to wait to see. HTH

[Meg McG]

I was asked by a colleague to help him convert a shapefile of a parcel into a .loc or .gpx file to be used a background so he may walk the boundary of a parcel and mark it out. Do you have any suggestions as to how to do this?
Any help would be much appreciated.
Thanks!

[Rich Owings]

You can convert shapefiles to .gpx files with OziExplorer.

Choose Map > Blank Map. Then File > Load from file > Import ESRI shapefile > Polylines. Then choose WGS 84 for the datum. Then File > Save to File > Export as GPX file.

[Meg McG]

Thanks so much for the info. Unfortunately I'm not in a position to spend $95 for just one small parcel. If anyone is interested in doing a conversion in the spirit of neighborliness, I'd appreciate it! Is there any other way?

[Rich Owings]

Meg,

I *think* you can use the free trial versions and do this, as long as you use the "blank map" feature and don't try to load a map.

[geeth]

i need a code for convert GPS coordinates to pixel values in a map

[Rich Owings]

If you have an image (map, aerial photo, etc.), you can use OziExplorer to "geo-reference" it. I think this may be what you are looking for...
http://gpstracklog.typepad.com/gps_tracklog/2006/08/software_for_po.html