Author Topic: glitches at map boundaries (Read 4531 times)

nevadarambler · « **on:** March 28, 2007, 11:57:33 PM »

Is there a way to improve the mapping of tracks that cross topo map boundaries? For example:

http://www.nevadarambler.info/hiking....325.gpx

This track crosses the Nevada/California border at longitude 120.00 and crosses UTM zones. Two problems: (1) Either the Nevada or California map can be seen, but not both together. (2) Where the track changes UTM zones, there is an obvious glitch in the mapping.

Neither of these problems is present with landsat images, just with the topos and aerials.

Krein · « **Reply #1 on:** March 29, 2007, 09:10:44 AM »

Hi,

Thanks for posting the link to your GPX file. I had optimized the calculation of UTM coordinates across zones for v3.0, but obviously it isn't giving the same results. I checked all of my files that cross zones and things seemed fine. This is the first problem I've seen.

If you want the fix, check out the beta version at

http://www.topofusion.com/beta.php

I reverted back to the original computation until I can sort it out.

As for viewing topos/aerials across zones, unfortunately it is not as easy as you might think it would be. The tiles are on grids based on the UTM zone they live in, so they overlap depending on the width of the zone -- basically the same calculation we do for tracks. It's certainly possible, but it wouldn't help much in your case. You might see some maps in the other zone, but you's still have the map collars in the way, since there's no way to detect when those are around.

Terraserver does have some lat/lon (geographic) projected topo tiles that do cross zones. I have been thinking about adding support for them. They would function just like the landsat tiles. Only problem is the maps are stretched the further you get from the equator, since they use a lat/lon projection rather than UTM. Still kinda cool, especially for the "bigger" picture views.

I tried loading the http pictures in your GPX and was puzzled when they wouldn't load. I'm getting a "forbidden" response from your server. Which is strange, because firefox seems to be able to download and view them. Any ideas why this might be so? I assume your copy of TF is able to load them?

Thanks for the feedback on this.

nevadarambler · « **Reply #2 on:** March 29, 2007, 08:16:44 PM »

Thanks for the quick response!

The photo thumbnails seem to work when the photos are on the local hard drive, but not when the URL prefix function is enabled.
I didn't get the forbidden page error, though, just the camera icons with no associated photos. The waypoint properties have the correct URL to the photos on my website.

Too bad about the map boundaries issue, it would be nice if the map servers took care of the map borders and splicing.

NevadaRambler

Krein · « **Reply #3 on:** April 01, 2007, 02:28:46 PM »

That's strange. TF is able to pull photos when I place them on topofusion.com.

Here is the response it's getting from your server:

<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<HTML><HEAD>
<TITLE>403 Forbidden</TITLE>
</HEAD><BODY>
<H1>Forbidden</H1>
You don't have permission to access /hiking/PeavineWest20070325/track/PeavineWest_20070325_145116.jpg
on this server.<P>
<P>Additionally, a 403 Forbidden
error was encountered while trying to use an ErrorDocument to handle the request.
<HR>
<ADDRESS>Apache/1.3.33 Server at AppStuff Port 80</ADDRESS>
</BODY></HTML>

It doesn't report an error, just silently fails to load the jpegs right now.

I've been taking a look but I still don't understand what that error message is about. If I take the url and use it in any web browser it loads the jpeg just find.

Any thoughts?