Home PageFacebookRSS News Feed
PocketGPS
Web
Read the current newsletter! Weekly
Newsletter
SatNav,GPS,Navigation
Pocket GPS World - SatNavs | GPS | Speed Cameras: Forums

Pocket GPS World :: View topic - Merging (aerial photo) maps
 Forum FAQForum FAQ   SearchSearch   UsergroupsUsergroups   ProfileProfile   Log in for private messagesLog in for private messages   Log inLog in 

Merging (aerial photo) maps

 
Post new topic   Reply to topic    Pocket GPS World Forum Index -> Memory-Map
View previous topic :: View next topic  
Author Message
MrT
Frequent Visitor


Joined: Nov 14, 2003
Posts: 2143
Location: Surrounded by A1, M1 & M25

PostPosted: Fri Jan 23, 2004 9:10 am    Post subject: Merging (aerial photo) maps Reply with quote

When two aerial maps are merged that are vertically adjacent, the merged map always has part missing. On the seam of the maps, the maps meet at each end but in the middle there is a white gap of some 250 metres of missing land. This information that is missing from the merge comes from the lower of the two maps and is present on the original, ie the gap is not due to a projection distortion but missing data from the merge.

If you have Region 4 Photo take a look at OS grid TL65,98 it seems a little odd.
Back to top
View user's profile Send private message
MikeB
Pocket GPS Staff
Pocket GPS Staff


Joined: 20/08/2002 11:51:57
Posts: 3859
Location: Essex, UK

PostPosted: Wed Feb 04, 2004 8:31 pm    Post subject: Reply with quote

Merging maps is not something I have needed to do until this week. The OS maps always seem to give me the right coverage in the middle of the map area.

Things changed this week when I needed to merge 2 sections of Nautical charts in the Florida Keys. These merged perfectly.

I suspect (but can't prove) that what is happening is that the Aerial Photos have blank calibrated collars which MM sees as being part of the map. When it overlays them and matches them up the blank collar is clearly visible. Does your blank area extend all the way across the join? If it does then this would be pretty conclusive.
_________________
Mike Barrett
Editor, PocketGPSWorld.com
Back to top
View user's profile Send private message Visit poster's website
MrT
Frequent Visitor


Joined: Nov 14, 2003
Posts: 2143
Location: Surrounded by A1, M1 & M25

PostPosted: Mon Feb 16, 2004 10:26 am    Post subject: Blank Area Reply with quote

The aerial photos meet at the ends of the join but there white gap is in the middle.

A horizontal merge works OK.

According to memory map support the aerial photos are not meant to be merged.
Back to top
View user's profile Send private message
TigerMoff
Occasional Visitor


Joined: Oct 22, 2003
Posts: 20

PostPosted: Fri Feb 20, 2004 4:24 pm    Post subject: Reply with quote

You will find that it is due to the curvature of the earth that there a gaps between the tiles (not missing sections). Memory map gets the top and bottom ends of the tile and joins them thus making a bow in the middle. This only happens in the 2004 OS edition since the calibration function was removed.
Back to top
View user's profile Send private message
MrT
Frequent Visitor


Joined: Nov 14, 2003
Posts: 2143
Location: Surrounded by A1, M1 & M25

PostPosted: Mon Feb 23, 2004 8:07 pm    Post subject: Reply with quote

TigerMoff wrote:
You will find that it is due to the curvature of the earth that there a gaps between the tiles (not missing sections). Memory map gets the top and bottom ends of the tile and joins them thus making a bow in the middle. This only happens in the 2004 OS edition since the calibration function was removed.


No, there is definitely missing image data at the join, images that are there on the original aerial photo's are missing on the the "gap" in the merged. It is not a gap between the two sets of data as would be caused by map curvature.

It is also nothing to do with the OS2004 program as compared to other versions. The 2003 versions do the same, as does the (non-OS) Memory Map Navigator 4.00 Build 345 2004 version which still has the calibration function.
Back to top
View user's profile Send private message
TigerMoff
Occasional Visitor


Joined: Oct 22, 2003
Posts: 20

PostPosted: Fri Feb 27, 2004 2:29 pm    Post subject: Reply with quote

Im sorry but I think we will have to agree to disagree on this one then. I have been able to merge maps with out any problem in the 2003 software using the 2003 maps.
Back to top
View user's profile Send private message
MrT
Frequent Visitor


Joined: Nov 14, 2003
Posts: 2143
Location: Surrounded by A1, M1 & M25

PostPosted: Sun Feb 29, 2004 5:27 pm    Post subject: TigerMoff Reply with quote

Can you let me know which Aerial Photo tiles you merged (vertically) so that I can try it with 2003? It may be that it only affects certain tiles?

Horizontal photo tile merges or maps where boundaries overlap by 20km have no problem.
Back to top
View user's profile Send private message
TC
Regular Visitor


Joined: Oct 22, 2003
Posts: 119
Location: Wiltshire, England

PostPosted: Wed Mar 03, 2004 1:02 pm    Post subject: Reply with quote

I also tried merging maps together and I am not impressed.

I have 2003 and tried merging UK(OS) regions (south-west, south wales - 1 and 3 I think) and got a big white gap. Yes I think the the map projection UTM is not applied correctly. It looks like on region gets the projection but the other is treated like a rectangular bitmap. In fact MM in my experience only realy likes dealing with one of anything e.g. one map (can be displayed) one elevation model (can be displayed) one places names.

I haven't tried this but I think if your meger maps successfully you will NOT get a merged elevation model or place name database. I'd like to be proved wrong.

Having said this I'd would like to say the I really like MM - it's by far and away better that Fugawi.
Back to top
View user's profile Send private message







Posted: Today    Post subject: Pocket GPS Advertising

Back to top
Display posts from previous:   
Post new topic   Reply to topic    Pocket GPS World Forum Index -> Memory-Map All times are GMT + 1 Hour
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

Powered by phpBB 2.0.11 © 2001 phpBB Group
phpBB port v2.1 based on Tom Nitzschner's phpbb2.0.6 upgraded to phpBB 2.0.4 standalone was developed and tested by:
ArtificialIntel, ChatServ, mikem,
sixonetonoffun and Paul Laudanski (aka Zhen-Xjell).

Version 2.1 by Nuke Cops 2003 http://www.nukecops.com

Make a Donation



CamerAlert Database

Click here for the PocketGPSWorld.com Speed Camera Database

Download Speed Camera Database
20.094 (28 Sep 22)



WORLDWIDE SPEED CAMERA SPOTTERS WANTED!

Click here to submit camera positions to the PocketGPSWorld.com Speed Camera Database


12mth Subscriber memberships awarded every week for verified new camera reports!

Submit Speed Camera Locations Now


CamerAlert Apps



iOS QR Code






Android QR Code







Terms & Privacy


GPS Shopping