UK aerial maps?

Terry Pinnell said:

Dennis Pogson said:

Terry Pinnell wrote:

<snip>

Quoted message said:

Quoted message said:

The results of my efforts so far can be seen in this 1.5 MB map,
showing the GPS track. What appear to be occasional cases of walking
on water are explainable by drought conditions, not any miraculous
qualities of my boots <g>.
http://www.terrypin.dial.pipex.com/Images/29Jun05BewlAerialRed1Annot.jpg

Quoted message said:

Unfortunately you don't mention scale, but the NASA Landsat 7
satellite aerial photography is freely available and is absolutely
stunning in it's detail, even from 435 miles up!

These can be downloaded from https://zulu.ssc.nasa.gov/mrsid/, once
you have mastered the technique, and are using broadband (they are
over 130mb each!). They come pre-calibrated in NAD25Conus datum,
Transverse Mercator projection, and are largely cloud-free over the
UK (don't ask me how they achieved this!) At maximum scale they are
approx 1:45,000. They will work in Oziexplorer if you download the
file conversion utility for these from the Oziexplorer site.

For sheer impact these will knock you socks off, but may be too
small a scale for your purpose.

You can download a simple viewer which enables you to section the
maps into smaller areas (tif files) from the Lizardtech site at
http://www.lizardtech.com/download/.

Have fun,

Dennis.

Thanks, Dennis, that looks a great source potentially. However, my
first attempts are not very promising! So far this is the closest I
can get ;-(
http://www.terrypin.dial.pipex.com/Images/UK1.jpg
Even that is already very pixellated, so presumably I have not yet
found the right places to click?

Going back to my map, I'm not sure how to specify the 'scale' of a map
converted to JPG? When effectively the same image is printed onto an
A4 sheet, my software (the excellent GPS Utility) displayed its scale
as about 22,600:1. And here is a zoom from the original JPG:
http://www.terrypin.dial.pipex.com/Images/BewlScale.jpg
As you see, it shows OS Grid references, 200m apart, so is just over 1
km wide.

Also, for convenience of possible further discussion, the intersection
of the 674 and 338 lines is at
OS TQ 674 338, or in full: 567400, 133800
or in Long/Lat: 51.07904 deg N, 0.38844 E

Any practical pointers you may be able to offer about using that
NASA site would be much appreciated please. I expect it will all be
embarrassingly obvious once I get the hang of it <g>. Can you for a
start tell me how to view even the small scale 'European' map without
the superimposed grid and text please?

Did you also see my reply to Colin? This satellite view
http://maps.google.co.uk/maps?q=bewl (then click 'Satellite'😉
is virtually *all* clouds!

You are not using the "select image" button. Just zoom in until the
reference numbers show, then select image. This brings up another page from
which you can download the image bounded by the rectangle on the first page.
Then just say where you want to save the download to, and go away to make
coffee or some other task whilst 135 mb of image is downloaded to your PC!

In article <[email hidden]>, Dominic Sexton said...

Quoted message said:

Quoted message said:

You need the 'correct' OS though, to start off with...

http://maps.google.com doesn't require anything other than your normal
browser (and isn't particularly bandwidth hungry either so does not
require broadband).

For some reason it's not working here - all I'm getting is a blank
screen instead of the pretty pictures everyone else is seeing. I
suspect a javascript error or something, but since everything seems OK
in the browser I'm stumped. I may do a quick reinstall or something
if I decide I've really had enough with it, and see if that works any
better.
--
/
Fran O(<|={
\

In article <[email hidden]>, Terry Pinnell
said...

Quoted message said:

Quoted message said:

And the appropriate software on your machine.

Could you clarify that please? What software, apart from a browser?

Things like javascript plugins, and whatever else it thinks it needs.
Sorry, I'm feeling grouchy here at the moment because various things
aren't working on my machine that should be. Googlemaps, for
instance.
--
/
Fran O(<|={
\

Terry Pinnell wrote...

Quoted message said:

Well, I can only repeat, that doesn't work here. For the standard
maps, fine. But not for aerial maps. Do you mean you ignore the fact
that the box is labeled 'Postcode', and enter a name or OS ref?

You have to enter the OS ref (6 fig) from the "Map Only" display and then
select "Aerial" once you have found your location.

David

Dominic Sexton said:

In article <[email hidden]>, Terry Pinnell
<[email hidden]> writes

Quoted message said:

Dominic Sexton said:

In article <[email hidden]>, Terry Pinnell
<[email hidden]> writes
>Anyone know of any other sources of (free) online UK aerial maps of
>comparable detail please? So far I've found MultiMap, which is OK. But
>am I right that the only route to get an aerial map is to enter the
>post code first? (Unlike the normal OS-based maps, which allow place
>names, co-ordinates, etc.)

You can put in grid refs (such as SJ935979). Village names also work.

Well, I can only repeat, that doesn't work here. For the standard
maps, fine.

In the aerial photos screen you can only search by postcode as you have
found. So instead you find what you want on the standard maps (with
postcode / place name / grid ref) and then click the camera icon above
the map to display the aerial photo.

If you want to go back to the map click the camera with a cross through
it that has replaced the camera icon.

You can zoom in / out and pan in either map or aerial photo view...

Excellent, thank you! I'd completely overlooked that camera icon tool.
I'm relatively unfamiliar with MM, having always rather preferred the
look of streetmap's maps; they look more like standard OS maps to me.
But this aerial facility could swing me back to MM. And the user
interface seems better designed too.

Going off at a tangent, my map is set to 50,000:1. I've never really
paused to interpret it before, but exactly what does that mean? I'm
*guessing* that it must apply to only one standard screen resolution?
If so, my money would be on 800 x 600. With a ruler against my 1024 x
768 screen, I measure the '2 Miles' at the map's base at about 8.5 cm.
Calculation gives 2 miles/25000 = 3.32 km/25000 = 6.6 cm. And 6.6/8.5
is also the same ratio as 800/1024. Am I right that 'resolution'
always refers to an 800 x 600 screen?

--
Terry, West Sussex, UK

David Lee said:

Terry Pinnell wrote...

Quoted message said:

Well, I can only repeat, that doesn't work here. For the standard
maps, fine. But not for aerial maps. Do you mean you ignore the fact
that the box is labeled 'Postcode', and enter a name or OS ref?

You have to enter the OS ref (6 fig) from the "Map Only" display and then
select "Aerial" once you have found your location.

Thanks, David, got it now, after Dominic explained that same point.
Obvious now I've seen it!

--
Terry, West Sussex, UK

Quoted message said:

NB follow up set

Terry Pinnell said:

just south of Kent. I've been using an image editor to piece together
a consolidated JPG map from captured sections of ECW screen, but it's
incredibly time consuming. Especially as there is no way of specifying
a consistent zoom level in the GetMapping viewer, so I find I have to
resize sections by trial and error to get them to fit!

I think using an image editor is the wrong way to stitch images to be
overlaid as maps. IMO you are better off noting a few known points on
the image and then calibrating the image with them. If the image is
already ortho rectified you only need to know 4 points near the
corners. Then load each calibrated tile into one of the free mapping
programs, add your track from the gps as a vector layer and capture
the image.

I thought Anquet or memory map could now supply aerial photos?

I imagine all the firms supplying this data will want to make copying
like this difficult. I do know that estate agents use a cd that
contains base mapping and aerial photos and can switch between or
combine views.

AJH (posting and reading from URW only so follow up set)

[Apologies if duplicated, but my previous send nearly 2 hours ago
appears to have vanished.]
---------

Thanks, but I'm going to have to study that hard, as I don't follow it
at my present level of skill. I prepared my track picture with GPS
Utility. Two calibration points were fine. However, as I said in my
OP, to get the calibration map for GPSU, I had to stitch together
several sections from different counties.

Simplifying a little, I had two images, Kent and East Sussex. Below
the irregular southern border of Kent, the image was grey. Similarly,
above the (identical) irregular border of East Sussex, the map was
grey. The area of my walk straddled the border.

Can you spell out the steps to proceed along the lines you suggest
please, and specify what software is necessary?

I'm sure Anquet and MemoryMap may be able to provide aerial maps. But
free?

--
Terry, West Sussex, UK

In article <[email hidden]>, Terry Pinnell
<[email hidden]> writes

Quoted message said:

Am I right that 'resolution'
always refers to an 800 x 600 screen?

Unfortunately not.

Physical screens have varying distances between the dots and the
developers have no way of knowing that spacing for an individual's
screen. Therefore the closest they can get to a real scale would still
be subject to that error.

In reality the scale of a digital raster map is defined by the size in
the real world of one pixel. The only ways to interpret that as a
physical scale is to either

(a) use the pixel size with the dot spacing of the display

or to
(b) measure the scale drawn with the map (or the distance
between grid lines where applicable).

Scale of images on a screen does not usually convey the same meaning as
on paper. It is usually just a relative term when used with different
scales of mapping from the same source - like multimap.

--

Dominic Sexton

Dave Fawthrop said:

| > | Not everywhere is covered, but try http://maps.google.com
| >
| > If you have broadband :-(
| >
| And the appropriate software on your machine.

Quoted message said:

The software is a big download, so no big problem.

The "software" for Google Maps is your web browser. I imagine you are
confusing Google Maps with Google Earth, which does indeed involve a
download and is not a web browser (though it has one built in, if not a
very good one).

Ed Seedhouse,
Victoria, B.C.

Fran said:

Quoted message said:

Quoted message said:

> | And the appropriate software on your machine.
>
> The software is a big download, so no big problem.
>
You need the 'correct' OS though, to start off with...

ITIYM the "wrong" OS? ;-)

Ha! Yes. Exactly. Buggrit, I'm going to have to 'upgrade'. Lots of
muttering going on here because although I'm running Windows I have no
particular problems with the version I'm using except that it's a
couple of years 'too old' soddit. Grump. Sounds like me.

Google Earth will run on Windows 2000 just fine. That's more than a
couple of years old.

Ed Seedhouse,
Victoria, B.C.

Dennis Pogson said:

Terry Pinnell said:

Dennis Pogson said:

Terry Pinnell wrote:

<snip>

Quoted message said:

> The results of my efforts so far can be seen in this 1.5 MB map,
> showing the GPS track. What appear to be occasional cases of walking
> on water are explainable by drought conditions, not any miraculous
> qualities of my boots <g>.
> http://www.terrypin.dial.pipex.com/Images/29Jun05BewlAerialRed1Annot.jpg

Quoted message said:

Unfortunately you don't mention scale, but the NASA Landsat 7
satellite aerial photography is freely available and is absolutely
stunning in it's detail, even from 435 miles up!

These can be downloaded from https://zulu.ssc.nasa.gov/mrsid/, once
you have mastered the technique, and are using broadband (they are
over 130mb each!). They come pre-calibrated in NAD25Conus datum,
Transverse Mercator projection, and are largely cloud-free over the
UK (don't ask me how they achieved this!) At maximum scale they are
approx 1:45,000. They will work in Oziexplorer if you download the
file conversion utility for these from the Oziexplorer site.

For sheer impact these will knock you socks off, but may be too
small a scale for your purpose.

You can download a simple viewer which enables you to section the
maps into smaller areas (tif files) from the Lizardtech site at
http://www.lizardtech.com/download/.

Have fun,

Dennis.

Thanks, Dennis, that looks a great source potentially. However, my
first attempts are not very promising! So far this is the closest I
can get ;-(
http://www.terrypin.dial.pipex.com/Images/UK1.jpg
Even that is already very pixellated, so presumably I have not yet
found the right places to click?

Going back to my map, I'm not sure how to specify the 'scale' of a map
converted to JPG? When effectively the same image is printed onto an
A4 sheet, my software (the excellent GPS Utility) displayed its scale
as about 22,600:1. And here is a zoom from the original JPG:
http://www.terrypin.dial.pipex.com/Images/BewlScale.jpg
As you see, it shows OS Grid references, 200m apart, so is just over 1
km wide.

Also, for convenience of possible further discussion, the intersection
of the 674 and 338 lines is at
OS TQ 674 338, or in full: 567400, 133800
or in Long/Lat: 51.07904 deg N, 0.38844 E

Any practical pointers you may be able to offer about using that
NASA site would be much appreciated please. I expect it will all be
embarrassingly obvious once I get the hang of it <g>. Can you for a
start tell me how to view even the small scale 'European' map without
the superimposed grid and text please?

Did you also see my reply to Colin? This satellite view
http://maps.google.co.uk/maps?q=bewl (then click 'Satellite'😉
is virtually *all* clouds!

You are not using the "select image" button. Just zoom in until the
reference numbers show, then select image. This brings up another page from
which you can download the image bounded by the rectangle on the first page.
Then just say where you want to save the download to, and go away to make
coffee or some other task whilst 135 mb of image is downloaded to your PC!

Thanks Dennis, penny finally dropped and downloading my first map now.
Can't be sure until I zoom further, but it *looks* as if the very
little cloud on this 128 MB section just happens to cover Bewl Water!

Don't recall handling a file with .TAR extension before; does it
decompress with the WinXP built in software (Compressed folder
thingies), or do I need something else like Winzip please?

--
Terry, West Sussex, UK

--
Terry, West Sussex, UK

Dominic Sexton said:

In article <[email hidden]>, Terry Pinnell
<[email hidden]> writes

Quoted message said:

Am I right that 'resolution'
always refers to an 800 x 600 screen?

Unfortunately not.

Physical screens have varying distances between the dots and the
developers have no way of knowing that spacing for an individual's
screen. Therefore the closest they can get to a real scale would still
be subject to that error.

In reality the scale of a digital raster map is defined by the size in
the real world of one pixel. The only ways to interpret that as a
physical scale is to either

(a) use the pixel size with the dot spacing of the display

or to
(b) measure the scale drawn with the map (or the distance
between grid lines where applicable).

Scale of images on a screen does not usually convey the same meaning as
on paper. It is usually just a relative term when used with different
scales of mapping from the same source - like multimap.

Thanks, understood.

It must be coincidence then that on my screen the scale appears to
match that calculation. It all seemed to hang together so logically
;-(

BTW, it seems that MultiMap must use the same aerial maps that are on
my High In The Sky CDs, namely the GetMapping ones. Here's a
screenshot showing three versions of same area, zoomed in to the
highest level I could before pixellation became too bad, corresponding
to 5,000 to 1 in Multimap:
http://www.terrypin.dial.pipex.com/Images/Bewl-Comparisons.jpg

Position Image
-------- -------
Left Multimap online
Middle JPG from original, in PaintShop Pro
Right Original ECW map in GetMapping viewer

--
Terry, West Sussex, UK

Terry Pinnell said:

Dennis Pogson said:

Terry Pinnell said:

"Dennis Pogson" <[email hidden]> wrote:

> Terry Pinnell wrote:

<snip>

>> The results of my efforts so far can be seen in this 1.5 MB map,
>> showing the GPS track. What appear to be occasional cases of
>> walking on water are explainable by drought conditions, not any
>> miraculous qualities of my boots <g>.
>>

http://www.terrypin.dial.pipex.com/Images/29Jun05BewlAerialRed1Annot.jpg

Quoted message said:

Quoted message said:

Quoted message said:

> Unfortunately you don't mention scale, but the NASA Landsat 7
> satellite aerial photography is freely available and is absolutely
> stunning in it's detail, even from 435 miles up!
>
> These can be downloaded from https://zulu.ssc.nasa.gov/mrsid/, once
> you have mastered the technique, and are using broadband (they are
> over 130mb each!). They come pre-calibrated in NAD25Conus datum,
> Transverse Mercator projection, and are largely cloud-free over the
> UK (don't ask me how they achieved this!) At maximum scale they are
> approx 1:45,000. They will work in Oziexplorer if you download the
> file conversion utility for these from the Oziexplorer site.
>
> For sheer impact these will knock you socks off, but may be too
> small a scale for your purpose.
>
> You can download a simple viewer which enables you to section the
> maps into smaller areas (tif files) from the Lizardtech site at
> http://www.lizardtech.com/download/.
>
> Have fun,
>
> Dennis.

Thanks, Dennis, that looks a great source potentially. However, my
first attempts are not very promising! So far this is the closest I
can get ;-(
http://www.terrypin.dial.pipex.com/Images/UK1.jpg
Even that is already very pixellated, so presumably I have not yet
found the right places to click?

Going back to my map, I'm not sure how to specify the 'scale' of a
map converted to JPG? When effectively the same image is printed
onto an A4 sheet, my software (the excellent GPS Utility) displayed
its scale as about 22,600:1. And here is a zoom from the original
JPG: http://www.terrypin.dial.pipex.com/Images/BewlScale.jpg
As you see, it shows OS Grid references, 200m apart, so is just
over 1 km wide.

Also, for convenience of possible further discussion, the
intersection of the 674 and 338 lines is at
OS TQ 674 338, or in full: 567400, 133800
or in Long/Lat: 51.07904 deg N, 0.38844 E

Any practical pointers you may be able to offer about using that
NASA site would be much appreciated please. I expect it will all be
embarrassingly obvious once I get the hang of it <g>. Can you for a
start tell me how to view even the small scale 'European' map
without the superimposed grid and text please?

Did you also see my reply to Colin? This satellite view
http://maps.google.co.uk/maps?q=bewl (then click 'Satellite'😉
is virtually *all* clouds!

You are not using the "select image" button. Just zoom in until the
reference numbers show, then select image. This brings up another
page from which you can download the image bounded by the rectangle
on the first page. Then just say where you want to save the download
to, and go away to make coffee or some other task whilst 135 mb of
image is downloaded to your PC!

Thanks Dennis, penny finally dropped and downloading my first map now.
Can't be sure until I zoom further, but it *looks* as if the very
little cloud on this 128 MB section just happens to cover Bewl Water!

Don't recall handling a file with .TAR extension before; does it
decompress with the WinXP built in software (Compressed folder
thingies), or do I need something else like Winzip please?

--
Terry, West Sussex, UK

Terry,

I use Winzip V8.0, as I prefer it to the XP unzipper, but I think XP will
unzip it. The actual map is on a file with a .sid suffix, which the
Lizardtech viewer can open. Subsequent files can be extracted from sections
by the Lizardtech viewer as .tif files, and saved in the same folder as the
viewer.

I have found the calibration (lat/lon) to be reasonably accurate, and I use
the photos as an additional aid to my sea charts, for navigation around the
West Coast. Obviously you have to insert town names and the names of lochs
etc, using a photo-editing program.

At full magnification, the scale, on a 1024 by 768 monitor is 1:45,600, or
about 1.6 inches per nautical mile, 1.34 inches per statute mile. This may
be somewhat smaller than you are used to for hiking etc., but is ideal for
sailing. Fields and roads are just visible, but don't expect the detail to
be like a 1" OS map, on which the roads and paths are not to scale of
course!

NASA re-colour the actual images to enhance the 3-D effect, which in
mountainous regions, is really impressive. Haven't downloaded the Himalayas
yet, but that would be interesting.

I understand that NASA are now going one further and are using a new,
even-higher-definition camera, so I am looking forward to having these
available when they have mapped the world ( for the third time!)

If you have any problems downloading the viewer, let me know.

Dennis.

Terry Pinnell said:

Dominic Sexton said:

In article <[email hidden]>, Terry
Pinnell <[email hidden]> writes

Quoted message said:

Am I right that 'resolution'
always refers to an 800 x 600 screen?

Unfortunately not.

Physical screens have varying distances between the dots and the
developers have no way of knowing that spacing for an individual's
screen. Therefore the closest they can get to a real scale would
still be subject to that error.

In reality the scale of a digital raster map is defined by the size
in the real world of one pixel. The only ways to interpret that as a
physical scale is to either

(a) use the pixel size with the dot spacing of the display

or to
(b) measure the scale drawn with the map (or the distance
between grid lines where applicable).

Scale of images on a screen does not usually convey the same meaning
as on paper. It is usually just a relative term when used with
different scales of mapping from the same source - like multimap.

Thanks, understood.

It must be coincidence then that on my screen the scale appears to
match that calculation. It all seemed to hang together so logically
;-(

BTW, it seems that MultiMap must use the same aerial maps that are on
my High In The Sky CDs, namely the GetMapping ones. Here's a
screenshot showing three versions of same area, zoomed in to the
highest level I could before pixellation became too bad, corresponding
to 5,000 to 1 in Multimap:
http://www.terrypin.dial.pipex.com/Images/Bewl-Comparisons.jpg

Position Image
-------- -------
Left Multimap online
Middle JPG from original, in PaintShop Pro
Right Original ECW map in GetMapping viewer

These are good, but compiling them into a reasonably sized map must be quite
a job?

In article <[email hidden]>, Ed Seedhouse
said...

Quoted message said:

Google Earth will run on Windows 2000 just fine. That's more than a
couple of years old.

Yes, but it doesn't like Win98.
--
/
Fran O(<|={
\

Dennis Pogson said:

Terry Pinnell wrote:

Quoted message said:

Quoted message said:

BTW, it seems that MultiMap must use the same aerial maps that are on
my High In The Sky CDs, namely the GetMapping ones. Here's a
screenshot showing three versions of same area, zoomed in to the
highest level I could before pixellation became too bad, corresponding
to 5,000 to 1 in Multimap:
http://www.terrypin.dial.pipex.com/Images/Bewl-Comparisons.jpg

Position Image
-------- -------
Left Multimap online
Middle JPG from original, in PaintShop Pro
Right Original ECW map in GetMapping viewer

These are good, but compiling them into a reasonably sized map must be quite
a job?

It did take a long time to make the full JPG I uploaded earlier
http://www.terrypin.dial.pipex.com/Images/29Jun05BewlAerialRed1Annot.jpg
but, as I explained, that was mainly because the source maps were in
two counties *with no overlap*.

Now that I have discovered that MultiMap's aerial maps are identical,
and don't suffer from that major snag, I reckon I could make that same
JPG from scratch in a fraction of the time!

--
Terry, West Sussex, UK

Dennis Pogson said:

Terry Pinnell said:

Dennis Pogson said:

Terry Pinnell wrote:
> "Dennis Pogson" <[email hidden]> wrote:
>
>> Terry Pinnell wrote:
>
> <snip>
>
>>> The results of my efforts so far can be seen in this 1.5 MB map,
>>> showing the GPS track. What appear to be occasional cases of
>>> walking on water are explainable by drought conditions, not any
>>> miraculous qualities of my boots <g>.
>>>

http://www.terrypin.dial.pipex.com/Images/29Jun05BewlAerialRed1Annot.jpg

Quoted message said:

Quoted message said:

>
>
>> Unfortunately you don't mention scale, but the NASA Landsat 7
>> satellite aerial photography is freely available and is absolutely
>> stunning in it's detail, even from 435 miles up!
>>
>> These can be downloaded from https://zulu.ssc.nasa.gov/mrsid/, once
>> you have mastered the technique, and are using broadband (they are
>> over 130mb each!). They come pre-calibrated in NAD25Conus datum,
>> Transverse Mercator projection, and are largely cloud-free over the
>> UK (don't ask me how they achieved this!) At maximum scale they are
>> approx 1:45,000. They will work in Oziexplorer if you download the
>> file conversion utility for these from the Oziexplorer site.
>>
>> For sheer impact these will knock you socks off, but may be too
>> small a scale for your purpose.
>>
>> You can download a simple viewer which enables you to section the
>> maps into smaller areas (tif files) from the Lizardtech site at
>> http://www.lizardtech.com/download/.
>>
>> Have fun,
>>
>> Dennis.
>
> Thanks, Dennis, that looks a great source potentially. However, my
> first attempts are not very promising! So far this is the closest I
> can get ;-(
> http://www.terrypin.dial.pipex.com/Images/UK1.jpg
> Even that is already very pixellated, so presumably I have not yet
> found the right places to click?
>
> Going back to my map, I'm not sure how to specify the 'scale' of a
> map converted to JPG? When effectively the same image is printed
> onto an A4 sheet, my software (the excellent GPS Utility) displayed
> its scale as about 22,600:1. And here is a zoom from the original
> JPG: http://www.terrypin.dial.pipex.com/Images/BewlScale.jpg
> As you see, it shows OS Grid references, 200m apart, so is just
> over 1 km wide.
>
> Also, for convenience of possible further discussion, the
> intersection of the 674 and 338 lines is at
> OS TQ 674 338, or in full: 567400, 133800
> or in Long/Lat: 51.07904 deg N, 0.38844 E
>
> Any practical pointers you may be able to offer about using that
> NASA site would be much appreciated please. I expect it will all be
> embarrassingly obvious once I get the hang of it <g>. Can you for a
> start tell me how to view even the small scale 'European' map
> without the superimposed grid and text please?
>
> Did you also see my reply to Colin? This satellite view
> http://maps.google.co.uk/maps?q=bewl (then click 'Satellite'😉
> is virtually *all* clouds!

You are not using the "select image" button. Just zoom in until the
reference numbers show, then select image. This brings up another
page from which you can download the image bounded by the rectangle
on the first page. Then just say where you want to save the download
to, and go away to make coffee or some other task whilst 135 mb of
image is downloaded to your PC!

Thanks Dennis, penny finally dropped and downloading my first map now.
Can't be sure until I zoom further, but it *looks* as if the very
little cloud on this 128 MB section just happens to cover Bewl Water!

Don't recall handling a file with .TAR extension before; does it
decompress with the WinXP built in software (Compressed folder
thingies), or do I need something else like Winzip please?

--
Terry, West Sussex, UK

Terry,

I use Winzip V8.0, as I prefer it to the XP unzipper, but I think XP will
unzip it. The actual map is on a file with a .sid suffix, which the
Lizardtech viewer can open. Subsequent files can be extracted from sections
by the Lizardtech viewer as .tif files, and saved in the same folder as the
viewer.

I have found the calibration (lat/lon) to be reasonably accurate, and I use
the photos as an additional aid to my sea charts, for navigation around the
West Coast. Obviously you have to insert town names and the names of lochs
etc, using a photo-editing program.

At full magnification, the scale, on a 1024 by 768 monitor is 1:45,600, or
about 1.6 inches per nautical mile, 1.34 inches per statute mile. This may
be somewhat smaller than you are used to for hiking etc., but is ideal for
sailing. Fields and roads are just visible, but don't expect the detail to
be like a 1" OS map, on which the roads and paths are not to scale of
course!

NASA re-colour the actual images to enhance the 3-D effect, which in
mountainous regions, is really impressive. Haven't downloaded the Himalayas
yet, but that would be interesting.

I understand that NASA are now going one further and are using a new,
even-higher-definition camera, so I am looking forward to having these
available when they have mapped the world ( for the third time!)

If you have any problems downloading the viewer, let me know.

Many thanks, Dennis, greatly appreciate your help, which has now
enabled me to successfully download a SID file and view it with
Express viewer (and save a few sections, in my case in JPG).

I had several problems, all apparently because I use Mozilla Firefox.
That explained the initial difficulty; I was using the Select Image,
but FF wasn't popping up that window. And then the Express viewer
would only work on MSIE, not FF. But I think all is now well!

I'll maybe get back to you with a few more detailed points later if
you don't mind?

Scale is a little too small for my purposes, but astonishing stuff in
its own right. I'm definitely going to have fun exploring the UK with
it <g>.

--
Terry, West Sussex, UK

Terry Pinnell said:

Thanks, but I'm going to have to study that hard, as I don't follow it
at my present level of skill. I prepared my track picture with GPS
Utility. Two calibration points were fine. However, as I said in my
OP, to get the calibration map for GPSU, I had to stitch together
several sections from different counties.

OK I am not familiar with GPSU, I was recommended gpstrackmaker which
David Lee has also replied with. I find this has the best interface
with my Garmin 12xl and I use it for loading track points with and
without base mapping.

The program I am more familiar with is mapmaker www.mapmaker.com, it's
a free download with 30 day trial of the full software when it reverts
to a basic mapping package, which fills most needs.

As long as the captured image is either ortho rectified (that is each
point on the image maps directly to the same projection as your datum
uses ( I set mine to ordnance survey grid and OSGB 36) or is small
enough that there is little deviation within the tile then you just
need two points which you can give grid references for.

Once all your tiles are calibrated then you assemble them in the
mapping program, they then form the base map for your walk, it doesn't
make any difference if these images are aerial photos or map tiles.

In fact when I was walking in Scotland the other week I took a high
resolution digital photo of a Harvey map calibrated this on 4 grid
intersections and planned a walk from mapmaker. As mapmaker is not as
easy to interface with the gps I exported these waypoints to
gpstrackmaker and uploaded them to my 12xl.

Quoted message said:

Simplifying a little, I had two images, Kent and East Sussex. Below
the irregular southern border of Kent, the image was grey. Similarly,
above the (identical) irregular border of East Sussex, the map was
grey. The area of my walk straddled the border.

Can you spell out the steps to proceed along the lines you suggest
please, and specify what software is necessary?

--
Terry, West Sussex, UK

NW Surrey here but I often walk and work in W sussex, have a go with
mapmaker and if you have trouble calibrating an image send it to me
with 4 control points marked and I will see about making a file which
will load ready for you to play with.

Quoted message said:

I'm sure Anquet and MemoryMap may be able to provide aerial maps. But
free?

No not free but I spend quite a lot of time playing with maps and any
body more gainfully employed could easily justify the expense of these
programs over the diy method.

AJH

Terry Pinnell said:

I have a set of UK aerial maps on CD from 'High In The Sky', which
were fairly expensive. They use ECW format files made by GetMapping.
It was an impulsive buy, and although I don't regret the expense, one
major snag I should have anticipated was the awkwardness of using them
around my locality.

The maps are sold by county, with no overlap whatsoever. I live on the
border of West Sussex and Surrey, with Kent too only a couple of miles
away. So any view in this area is likely to be partially grey,
representing the adjacent county. Same thing happens anywhere near a
border. For example, yesterday I was making a view of a 13 mile walk I
did last week around Bewl Water - which happens to lie in East Sussex,
just south of Kent. I've been using an image editor to piece together
a consolidated JPG map from captured sections of ECW screen, but it's
incredibly time consuming. Especially as there is no way of specifying
a consistent zoom level in the GetMapping viewer, so I find I have to
resize sections by trial and error to get them to fit!

Anyone know of any other sources of (free) online UK aerial maps of
comparable detail please? So far I've found MultiMap, which is OK. But
am I right that the only route to get an aerial map is to enter the
post code first? (Unlike the normal OS-based maps, which allow place
names, co-ordinates, etc.)

The results of my efforts so far can be seen in this 1.5 MB map,
showing the GPS track. What appear to be occasional cases of walking
on water are explainable by drought conditions, not any miraculous
qualities of my boots <g>.
http://www.terrypin.dial.pipex.com/Images/29Jun05BewlAerialRed1Annot.jpg

I know it is not a free solution but Memory-Map is the ideal solution, it
has calibrated 1:25000 and 1:25000 OS mapping with aerial mapping and you
can overlay a GPS track simply and easily. For one or two tiles its not
overly expensive.

--
Darren Griffin
PocketGPSWorld - www.PocketGPSWorld.com
The Premier GPS Resource for News, Reviews and Forums
Creators of the free UK Safety Camera POI

Quoted message said:

Terry Pinnell said:

Thanks, but I'm going to have to study that hard, as I don't follow it
at my present level of skill. I prepared my track picture with GPS
Utility. Two calibration points were fine. However, as I said in my
OP, to get the calibration map for GPSU, I had to stitch together
several sections from different counties.

OK I am not familiar with GPSU, I was recommended gpstrackmaker which
David Lee has also replied with. I find this has the best interface
with my Garmin 12xl and I use it for loading track points with and
without base mapping.

The program I am more familiar with is mapmaker www.mapmaker.com, it's
a free download with 30 day trial of the full software when it reverts
to a basic mapping package, which fills most needs.

As long as the captured image is either ortho rectified (that is each
point on the image maps directly to the same projection as your datum
uses ( I set mine to ordnance survey grid and OSGB 36) or is small
enough that there is little deviation within the tile then you just
need two points which you can give grid references for.

Once all your tiles are calibrated then you assemble them in the
mapping program, they then form the base map for your walk, it doesn't
make any difference if these images are aerial photos or map tiles.

In fact when I was walking in Scotland the other week I took a high
resolution digital photo of a Harvey map calibrated this on 4 grid
intersections and planned a walk from mapmaker. As mapmaker is not as
easy to interface with the gps I exported these waypoints to
gpstrackmaker and uploaded them to my 12xl.

Quoted message said:

Simplifying a little, I had two images, Kent and East Sussex. Below
the irregular southern border of Kent, the image was grey. Similarly,
above the (identical) irregular border of East Sussex, the map was
grey. The area of my walk straddled the border.

Can you spell out the steps to proceed along the lines you suggest
please, and specify what software is necessary?

--
Terry, West Sussex, UK

NW Surrey here but I often walk and work in W sussex, have a go with
mapmaker and if you have trouble calibrating an image send it to me
with 4 control points marked and I will see about making a file which
will load ready for you to play with.

Quoted message said:

I'm sure Anquet and MemoryMap may be able to provide aerial maps. But
free?

No not free but I spend quite a lot of time playing with maps and any
body more gainfully employed could easily justify the expense of these
programs over the diy method.

AJH

Many thanks for that very helpful follow-up. I'll experiment further
and report back later.

But, unless I'm still missing something very basic (quite likely on
previous experience!), the crucial difficulty I had still sounds as if
it might cause a problem, even in MapMaker/TrackMaker. My aerial maps
were non-overlapping maps. By map 'tiles' I assume you mean
overlapping tiles? As explained, extracts or captures from my
GetMapping aerial views *have* no overlap. So I presume that when
MapMaker (or any program) attempts to assemble 2 or more 'tiles' it
would end up with the same problem that I do when trying to perform
that task visually in an image editor. I had to transform the
irregular grey areas on each tile to transparency first. Wouldn't
MapMaker/TrackMaker face the same obstacle?

--
Terry Pinnell, West Sussex, UK