[OZAPRS] UI-VIEW Map Specification?

[Richard Hoskin]

Hi Chris,

This sounds like a great project. The maps could also be used on the new
findU map server. See http://aprsmm.aprs.net

UI-View considers the world to be flat, so the larger the map scale the
better. (The more accurate the maps at the edges)

It was voted several years ago on this list to use WSG84 or GDA94 as the
Australian APRS Datum Standards. I understand that there is only a few
centimetres difference between them. This is not a problem for our use of
maps.

The size of the map is important in UI-View. The size a PC can load is
limited by the PCs physical RAM minus a number of other parameters that
depend on the PC's O/S other applications running etc. I have found that
maps in the range of 3Mb in size are ok for most entry level PCs with 64Mb
for RAM. PNG is the preferred file format.

I would recommend that you include plenty of comments in the .INF file.
Comments such as; Date of manufacture, Name of manufacturer, Datum type
used, Base map reference, Estimated accuracy etc.

It would be nice to have each map overlap with the other by a few percent
so you don’t get impacted by the edge of map syndrome.

It would be great if the maps were also available in Pocket APRS format
(wish list:) as there has been a number of requests for maps of Australia
in this format but I don’t believe that any are available.

Cheers
Richard.
VK3JFK



>From UI-View Map Help:

Maps should have a colour depth of at least 256 colours. GIFs are much
smaller than BMPs in terms of disk space, but BMPs load faster. For drawn
images such as maps, JPG files often do not compress as well as PNGs and
GIFs, and the lossy compression of JPG can spoil the image quality.

UI-View32 assumes that North is the top of the map, that latitude changes
linearly along the Y axis and that longitude changes linearly along the X
axis. If the maps do not meet those conditions then inaccuracies in
plotting will occur.

For each map BMP, PNG, GIF, JPG or EMF file, there must be a matching INF
file. E.g. if you have a map called GB.GIF then there must also be a file
called GB.INF. AN easy way to create the INF file is to create the map
graphics file, save it in the MAPS folder, then drag it from Explorer and
drop it onto the map window. The Create An INF File dialogue will then
open.

INF File Format
First line - the longitude and latitude of the top left corner of the map,
separated by a comma. It doesn't matter whether longitude or latitude is
first on the line.

Second line - the longitude and latitude of the bottom right corner of the
map, separated by a comma. It doesn't matter whether longitude or latitude
is first on the line.

Third line - up to 30 characters of description.

Format of longitude and latitude - [dd]d.mm.n[n]<NESW>.
d[dd] = degrees, one to three digits.
mm = minutes
n[n] = decimal minutes, one or more decimal places (NOT seconds)


-----Original Message-----
From: Chris Hill [mailto:chris.hill at crhtelnet.com.au]
Sent: Friday, 5 March 2004 12:00 PM
To: ozaprs at marconi.ics.mq.edu.au
Subject: [OZAPRS] UI-VIEW Map Specification?

Hi All,

I am going to try to procure some maps which can be legally used for
Amateur Radio purposes, covering VK6, for use in (eg) UI-VIEW.

Does anyone know what specifications I need to state when ordering the
maps?

- Am I right in thinking that UI-VIEW requires a simplistic rectangular
projection?

- What Geodetic Datum should I ask the map to be presented in?  (WGS84?)

- Anything else?

Any pointers gratefully received.



73



Chris
VK6KCH


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