[aprssig] Default find.cgi scale

Robert Bruninga bruninga at usna.edu
Mon Nov 15 12:45:11 EST 2004

>>It would be nice if the zoom scale was compatible with
>>the APRS range scale standard.... Users have a good 
>>feel for what say a "16 mile range scale" will get them...
>>... but "0.04" doesnt 

>>> Steve Dimse <k4hg at tapr.org> 11/15/04 11:45:57 AM >>>
>The number represents roughly the degrees longitude 
>covered by the map.

I dont think users think that way.  They think in terms of
how big of an area do they want to see around their
station.  That is what "range scale is"...

> However [the longitude factor] is a continuous variable 
>unlike the arithmatic progression you use for map scales. 

Range scale is not required to be integer powers of 2.
It is simply asking that you state the size of a map in the
APRS standard way of specifying its range scale.
A 16 mile range means that all of the map within 16
miles of the center is visible...

>I do not see a reason to limit my users to a handful of map 
>scales when the system is capable of much more.

I agree.  Just let them specify the parameter in the APRS 
standard of range scale in miles which is more user friendly.

>As to matching the units to yours, this is not something 
>people will be communicating to each other, a user will 
>find the number that produces the map he likes, and create 
>a link using that value, so there is no benefit to changing it.

I disagree.  Why force everyone to hunt-and-peck to find
a suitable longitude scale factor when anyone can make a 
pretty darn good first guess by simply knowing the Range Scale
he wants.  If he wants a  map that shows everything
16 miles around him, then why not let him enter the range
scale of "16".   That sure seems user friendly to me...

APRS range scale does not require integer powers of 2.
It is simply a consistent way for users to specify the size
of their map view by the range of the map..  It can also be 
in Kilometers if desired.


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