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Dear Friends,

In respect to the creation of high detailed maps, I plan to scan some ordnance maps of my town and local area. These are extremely detailed and I will probably manage to make my town screen filling, covering an area of some 2 by 2 miles.

I think the most accurate way of getting the right coordinates for the INF file is to actually drive to the upper left corner point on the map and read GPS coordinates at that point. Secondly you drive to the right lower corner and read the coordinates over there. Using this method elimates any inaccuracies which has been made by the producers of commercial maps.
It should be possible to get an accuracy within 50 yards or so. The same device which is used for position reporting on a map has been used for calibriation of the same map.

More accurate would not be possible, would it?

Any reactions on the above idea are welcome.

Alex Buurlage
PA3FJQ

Hi All

I'm currently experimenting with UI-View with the intention of using the
system on future Raynet events. The biggest problem I have is producing
suitable maps that are accurate enough for the purpose. I need street
level maps that I can zoom out of, by changing to another map, to get the
coverage of the event.

For example in July I am organizing the Raynet coverage of the Big H Cycle
Ride. This starts at Hampton Court and ends at Hove, so it starts in
London crosses Surrey and ends up on the South Sussex Coast, in all 60
miles. I want to monitor the sweep vehicle by plotting every couple of
minutes. The map of the whole area is of fairly small scale. The idea is
to monitor progress on a map of the entire route, but should it be
necessary to locate the vehicle with some accuracy then I would change to a
street level map of the last known position.

All this requires maps of some accuracy. The ones I have at present will
not do, for example travelling 9 miles last evening , my destination put me
on the Northern side of the M25 whereas I was on the Southern side - on the
map my position was around 2 - 3 miles out.

As yet I haven't worked out a method of producing the accuracy needed.

Anyone any ideas?

73

Brian

In article <200003160310_MC2-9D4B-1AD1@...>, Brian Davies
<brian_j_davies@...> writes

From: Brian Davies <brian_j_davies@...>

[snip]

All this requires maps of some accuracy. The ones I have at present will
not do, for example travelling 9 miles last evening , my destination put me
on the Northern side of the M25 whereas I was on the Southern side - on the
map my position was around 2 - 3 miles out.

The UK maps supplied with UI-View were all made from the Attica atlas.
The Boston map locates me with great precision. All my other maps made
from that atlas are similarly accurate, I have never seen an error
remotely approaching 2 to 3 miles.

So, I would say that you're either doing something wrong when making the
maps, or the data source you're using contains fundamental inaccuracies.
If you're not using the Attica atlas, try this when you're making a map
in whatever program you're using:-

Hold the mouse in the top left corner and note the longitude, then move
it to the bottom left corner and note the longitude - the values should
be the same. Do the same with the two top corners, but note the
latitudes, again the values should be the same. If the values are
different, then the maps are drawn on some other grid, (in the UK they
will probably be drawn on an NGR grid) and you are bound to get
inaccuracies.

--
Roger Barker, G4IDE - roger@...
For UI-View goto to -
For WinPack goto to -

Send me your home long/lat and I will produce a street level map around your location. If that is ok I will detail the way I produce mine.

----------
From: Brian Davies
Sent: Thursday, March 16, 2000 8:10 AM
To: INTERNET:ui-view@...
Subject: [ui-view] Practical uses for UI-View

<<File: ATT00002.html>>

In article <gH1LPBAUdK04Ew9x@...>, Roger Barker
<roger@...> writes

From: Roger Barker <roger@...>

In article <200003160310_MC2-9D4B-1AD1@...>, Brian Davies
<brian_j_davies@...> writes

From: Brian Davies <brian_j_davies@...>

[snip]

All this requires maps of some accuracy. The ones I have at present will
not do, for example travelling 9 miles last evening , my destination put me
on the Northern side of the M25 whereas I was on the Southern side - on the
map my position was around 2 - 3 miles out.

The UK maps supplied with UI-View were all made from the Attica atlas.
The Boston map locates me with great precision. All my other maps made
from that atlas are similarly accurate, I have never seen an error
remotely approaching 2 to 3 miles.

Agreed. I too use the Attica, and my most detailed map covers a distance
of 8 miles from top to bottom. When testing the map's accuracy, by
driving in opposite directions on the same road, it was easy to see
which side of the road I was on. The greatest inaccuracy was just a few
tens of feet, not 2-3 miles.

However, I have also tried using Info Map 98, which shows my home QTH
about half a mile west from where it really is. Totally useless. I'm
returning the package to where I bought it from.

Look out for version 2 of the Attica package at rallies. It's not the
latest, but it's probably entirely adequate for APRS. I saw several CD
vendors selling it at Picketts Lock on Sunday for around GBP 9.00.

73
Ian, G3NRW
Technical Editor, APRS Protocol Specification

--
+-----------------------------------------------------------------+
| APRS on 144.800 [IO91SX] ~55km/35 miles NNW of London |
| email: g3nrw@... |
| |
| APRS PROTOCOL SPEC:
+-----------------------------------------------------------------+

From: Brian Davies <brian_j_davies@...>

Hi All

I'm currently experimenting with UI-View with the intention of using the
system on future Raynet events. The biggest problem I have is producing
suitable maps that are accurate enough for the purpose. I need street
level maps that I can zoom out of, by changing to another map, to get the
coverage of the event.

For example in July I am organizing the Raynet coverage of the Big H Cycle
Ride. This starts at Hampton Court and ends at Hove, so it starts in
London crosses Surrey and ends up on the South Sussex Coast, in all 60
miles. I want to monitor the sweep vehicle by plotting every couple of
minutes. The map of the whole area is of fairly small scale. The idea is
to monitor progress on a map of the entire route, but should it be
necessary to locate the vehicle with some accuracy then I would change to a
street level map of the last known position.

All this requires maps of some accuracy. The ones I have at present will
not do, for example travelling 9 miles last evening , my destination put me
on the Northern side of the M25 whereas I was on the Southern side - on the
map my position was around 2 - 3 miles out.

As yet I haven't worked out a method of producing the accuracy needed.

Anyone any ideas?

73

Brian

Hi Brian,

We have used UI on several Raynet events now without problems.

Maps have been generated from both Nav progs (down to steet level)
and from scanned input.

The accuracy is generally quite good with errors only starting to
become noticeable at 1:25000 scale, and some of that is due to
the Selective Availability on the Sats..

I can only suggest that you look at the inf files and verify that
the co-ordinates are correct.

To give you some idea of what can be done the NGR cursor readout in
UI is in very close agreement with the grid lines on a scanned section of
a 1:25000 (2 1/4" to the mile) OS map.

73
Jeff G8HUL

Hi All

Many many thanks for all the replies to my comments regarding map accuracy.
Head hung in shame it would certainly appear that my problem is going to
be the accuracy with which I create the relevant map. I will try to do
better in future.

Incidently I am using various maps including Attica Knowledge Series Third
Edition - The Ordnance Survey Interactive Atlas of Great Britain. Is this
the map you are referring to?

73

Brian

In article <200003161130_MC2-9D5A-76B1@...>, Brian Davies
<brian_j_davies@...> writes

Incidently I am using various maps including Attica Knowledge Series Third
Edition - The Ordnance Survey Interactive Atlas of Great Britain. Is this
the map you are referring to?

Yup.

73
Ian, G3NRW
Technical Editor, APRS Protocol Specification

--
+-----------------------------------------------------------------+
| APRS on 144.800 [IO91SX] ~55km/35 miles NNW of London |
| email: g3nrw@... |
| |
| APRS PROTOCOL SPEC:
+-----------------------------------------------------------------+

In article <200003161130_MC2-9D5A-76B1@...>, Brian Davies
<brian_j_davies@...> writes

From: Brian Davies <brian_j_davies@...>

Hi All

Many many thanks for all the replies to my comments regarding map accuracy.
Head hung in shame it would certainly appear that my problem is going to
be the accuracy with which I create the relevant map. I will try to do
better in future.

Incidently I am using various maps including Attica Knowledge Series Third
Edition - The Ordnance Survey Interactive Atlas of Great Britain. Is this
the map you are referring to?

That's the one I use. The second edition, sometimes given away as a
magazine cover CD, is equally accurate. Make sure you run it full screen
when you make maps, and, if you're using Win95 or later, first hide the
Windows task bar, so it really does go full screen. Drag the mouse hard
into the top left and bottom right corners and note the lat and long for
the INF file. Use "Print", "Save to File" to save the image.

--
Roger Barker, G4IDE - roger@...
For UI-View goto to -
For WinPack goto to -

Hi All

Many many thanks to all of you whom have sent me messages regarding my map
problems on UI-View. I have been able to recognize that my problem has
been the way I have tried to make the maps. The information sent by
several of you have helped me enormously and I'm duly most grateful.

Once again many thanks for all your help.

73

Brian G3OYU
County Controller Surrey Raynet.

From: Ian Wade <Ian.Wade@...>

Sorry to labour this Jeff, but when you're using UI-View, you are still
using APRS.

Yes Ian, some of us have the message now ;-)

The UI-View implementation of APRS may not handle all these things
today, but Roger is catching up fast, and on a roll towards overtaking
all the other implementations, in very short order I suspect.

Ah ha, so those of us that suggested that slavishly following the 'US'
system was not necessarily a 'good idea', and that developing an alternate
way of doing things may provide a better way for the UK (or even, never let
it be suggested, better for Europe)?

May I humbly suggest that, had Roger succumbed to the WinAPRS way from day
one, then UI-View would not have developed to the point where it challenges
some of the ways that that way of implementing the APRS protocol does things.

But, hey, what do I know about it?

:-)

de Dave (G0DJA)