# default hours and step size
$numhours = 3 unless $numhours && $numhours =~ /^\d+$/;
+$numhours = 3 if $numhours < 0;
+$numhours = 24 if $numhours > 24;
$step = 5 unless $step && $step =~ /^\d+$/;
+$step = 5 if $step < 0;
+$step = 30 if $step > 30;
# get nearest lat and long (I can see we will need the altitude here soon as well :-)
my $lat = $self->user->lat;