Porting code from Google API requires calculating zoom and center parameters

[mrdvt92]

I'm trying to port some code from the old Google API to your docker which uses the Perl package Geo::Google::StaticMaps::V2. The issue is that both center and zoom parameters are required for your API but, they were not required for the Google API. I request that you add the business logic to calculate reasonable defaults when not specified.

• To calculate a reasonable center, it could use the average of the bounding box e.g. avg(min(lat), max(lat)), avg(min(lon), max(lon))
• To calculate a reasonable zoom, from the bounding box, you might be able to reverse this process discussed at Stack Overflow

An example with hard coded zoom and center.

perl -MGeo::Google::StaticMaps::V2 -E '
my $lat  = shift || 38.780676;
my $lon  = shift || -77.387105;
my $zoom = shift || 14;
my $map  = Geo::Google::StaticMaps::V2->new(server=>"localhost:3000", script=>"/map.png");
$map->marker(location=>{lat=>$lat, lon=>$lon});
$map->center(join(",", $lat, $lon));
$map->zoom($zoom);
say $map->url;
'

Returns: http://localhost:3000/map.png?size=600x400&sensor=false&markers=38.780676%2C-77.387105&center=38.780676%2C-77.387105&zoom=14

[mrdvt92]

This Stack article has a direct zoom calculation based on bounding box. It also recommends minimum zoom of 15.

var zoom = Math.round(Math.log(pixelWidth * 360 / angle / GLOBE_WIDTH) / Math.LN2);

In Perl I ported as

my $angle  = abs($lon1 - $lon2); $angle += 360 if $angle < 0;
my $zoom   = int(log($map->width * 360 / $angle / 256) / log(2)); #log base 2 = ln(x)/ln(2)