<disclaimer>
The following contains reference to a Shareware
program that I wrote, so the content of this
message may not be suitable for all audiences.
</disclaimer>


Background
----------
There once was a website named Toporama ...
Well, there actually was such a website, but it
is no longer available. Through that website you
could get 1:50,000 and 1:250,000 scale topographic
map images in GIF format. They had been computer-
generated, and had no map collar. Typical image
size was 3200x1600 pixels. All the images corresponded
to the Canadian National Topographic System (NTS)
mapsheet numbering scheme. There were limitations for
those map images, such as no labels on contour lines:
http://members.shaw.ca/davepatton/drgmapcal/Toporama_I_example.png


Toporama II
-----------
More recently, the Canadian government updated the
Atlas of Canada website with a new mapping interface:
http://atlas.nrcan.gc.ca/site/english/maps/topo/map
They used the "Toporama" name on the website, but
at least when the website was first updated, the
only "map image" you could obtain was by doing a
'save' of the image displayed in the browser window,
which was only part of an NTS mapsheet. The Atlas
of Canada website makes use of a 'Toporama Web
Mapping Server' that in turn makes use of the
CanVec product:
http://geogratis.ca/geogratis/en/service/toporama.html
In addition to the availability of the Atlas of Canada
website and the Toporama WMS service, the government
used the Toporama WMS service to generate Toporama
GeoTIFF map images:
http://geogratis.ca/geogratis/en/collection/detail.do?id=36765
These Toporama GeoTIFF map images can be downloaded
directly via a web browser or FTP:
http://ftp2.cits.nrcan.gc.ca/pub/toporama/
ftp://ftp2.cits.nrcan.gc.ca/pub/toporama/
The quality of these "Toporama II" map images is much better
than the original Toporama I GIF images:
http://members.shaw.ca/davepatton/drgmapcal/Toporama_II_example.png


Using the Toporama II images in Ozi
-----------------------------------
You can simply download the Toporama II map image ZIP file,
extract the GeoTIFF image, and Import it into OziExplorer.

Here's what I do to use the Toporama II GeoTIFF map images:
1)
Download the ZIP files that cover your area(s) of interest.
I download from the "50k_geo_tif" directory, because I want
the map images that were generated using Geographic projection.
In other words, a latitude/longitude or plate carrée projection.
These map images can be easily tiled together. The UTM projection
map images are generated in a manner that results in overlap
between adjacent NTS mapsheets, making it harder to tile the images.
2)
Put all the download ZIP files into one directory. Using a recent
version of 7-Zip (http://www.7-zip.org/) open the 7-Zip File Manager,
select all the ZIP files, and "Extract Here". Once it is done, I
delete all the other files, leaving just the ZIP and GeoTIFF files.
3)
The Toporama II GeoTIFF images are 24-bit uncompressed TIFF files.
That means that OziExplorer has to load the entire map image into
memory. A typical map image size is 4500x3600 pixels, resulting in a
size on disk of over 46MB. Because they are uncompressed, that is
true even for an image such as toporama_092a13_1_0_geo.tif which is
almost all just a white background (In fact, you won't see the
092A13 as a 'normal' NTS mapsheet designation. In this case, the
map image was generated to properly show the small portion of
the Canadian landmass that is below 49 degrees North at the
Southern edge of the 092H04 mapsheet).
It is easy to convert the images to a 'better' format for use
with OziExplorer. I use the batch processing facility of IrfanView
http://irfanview.com/
I set the output format to be TIF, with LZW compression. Despite
what it says in the Ozi Help file, recent Ozi versions can read
LZW-compressed images. I also change the color depth to 256 colors.
I keep the image size and file name the same.
As an example, taking 73 of these Toporama II GeoTIFF map images
and using IrfanView to convert them to 256-color LZW-compressed
TIFF images went from 3.3GB of space to 323MB of disk space.
Not only are the resulting images much smaller, but because they
are 256-color images, OziExplorer can just load the required
part of the map image into memory, rather than the entire image.
4)
Then I generate the OziExplorer .map calibration files for the
converted TIFF(not GeoTIFF) map images by using my DRGMapCal program:
http://members.shaw.ca/davepatton/drgmapcal/
I wrote DRGMapCal originally to generate Ozi .map files for the
Toporama I GIF map images, even if people had modified the size of
the map image. As a result, DRGMapCal can generate the .map files for
the Toporama II map images without the need for the georeferencing
information in the GeoTIFF files, and do it properly even though the
Toporama II images are not the same sizes as the Toporama I images.
This is one reason that I download the Toporama II map images that
are in the Geographic projection, because running DRGMapCal against
the UTM-projected Toporama II map images would generate incorrect
OziExplorer .map calibration files.


--
Dave Patton
CIS Canadian Information Systems
Victoria, B.C.

Degree Confluence Project:
Canadian Coordinator
Technical Coordinator
http://www.confluence.org/

Personal website:
Maps, GPS, etc.
http://members.shaw.ca/davepatton/