Ships Using APRS?

This is an aprs.fi screen shot from a few minutes ago just off the east coast of Florida. Anyone have any idea why ships or boats are using APRS? Seems to be very popular!



Sam, just wondering if you have a better way of inserting screen shots into a post other than what I did. I did a "Print Screen" onto my clipboard then copied the contents into a photo editing programs, saved as .jpg, and entered into this post the normal way. Doesn't appear to be as clear as yours! And sorry about the wrong category; can you re-direct to APRS? Thanks.

Actually, they're not using APRS. What you're seeing are AIS (Automatic Identification System) tracks. AIS is like ADS-B for ships; it broadcasts the ship's name, position, speed, draft, etc.

Inexpensive AIS receivers are easy to find, and some folks close to the water have them set up to send AIS tracks to APRS servers - which is why you see them on aprs.fi.

hth,

Dave

Pat Hatch said:

Sam, just wondering if you have a better way of inserting screen shots into a post other than what I did. I did a "Print Screen" onto my clipboard then copied the contents into a photo editing programs, saved as .jpg, and entered into this post the normal way.

Click to expand...

Pat, that's the way I handle the maps. I sometimes apply a little unsharp mask in PhotoShop. Your grab looked pretty good to me.

.jpg compression is going to cause a bitmap to look a little "fuzzy" because it is lossy. You won't notice that so much with a photgraph.

Some programs let you choose the compression level... less compression will look better, at the cost of a larger file size.

The only thing I would recommend when posting screenshots (or any other drawing, etc) is to not save them as JPEGs. It's a pet peeve of mine (I'm an anal retentive programmer). JPEGs are intended for photographs...not graphics. JPEG is a lossy format, which is why your screenshot is almost illegible. Save the image in PNG or GIF, which are both lossless and your screenshots will look at good as the original.

Thanks!

Yeah, thanks guys...Sam, I usually do hit the 'auto sharpen' enhancement in Photoshop, will try it next time. I thought .PNG would take up too much bandwidth, but I'll try it next time.