Then Mojo it is. Thanks so much for your post, Util, it helped me get farther in a lot of ways. I was able to get this to work on the command line, but I couldn't get Corion's curl converter to recognize a -S option, nor could I see it from man curl. The command seems to give the same output without it:

$ curl -s 'https://nationalmap.gov/epqs/pqs.php?units=Meters&output=js
+on&x=-83.65&y=41.37' | jq '.USGS_Elevation_Point_Query_Service.Elevat
+ion_Query.Elevation'
212.77
$
[download]

Unfortunately, I couldn't get this value in the perl script which I'm posting below. (Partial credit is great for me.)

I was thrilled to see this solution at the same server where I had been fishing! Furthermore, your example along with the jq command to see where the good data is in the haystack was exactly what I needed to get some numbers out of this. First I'll post the log then the source.

2020/06/23 15:26:07 INFO ./5.2.elev.pl 
2020/06/23 15:26:07 INFO {
  "USGS_Elevation_Point_Query_Service" => {
    "Elevation_Query" => {
      "Data_Source" => "3DEP 1/3 arc-second",
      "Elevation" => -1000000,
      "Units" => "Meters",
      "x" => "41.37",
      "y" => "-83.65"
    }
  }
}
 
2020/06/23 15:26:07 INFO 41.37 -83.65 0.208 
2020/06/23 15:26:07 INFO ============== 
2020/06/23 15:26:07 INFO https://api.weather.gov/points/41.37,-83.65 
2020/06/23 15:26:08 INFO CLE 
2020/06/23 15:26:08 INFO 16  52 
2020/06/23 15:26:08 INFO ============== 
2020/06/23 15:26:08 INFO https://api.weather.gov/gridpoints/CLE/16,52 
2020/06/23 15:26:08 INFO ============== 
2020/06/23 15:26:08 INFO 213.0552 wmoUnit:m
[download]

Source:

#!/usr/bin/env perl

use strict;
use warnings;
use 5.016;
use Log::Log4perl;
use Mojo::UserAgent;
use open ':std', OUT => ':utf8';
use Mojo::Util qw(dumper);

# get rid of old log
my $file = '/home/hogan/Documents/hogan/logs/4.log4perl.txt';
unlink $file or warn "Could not unlink $file: $!";
my $log_conf4 = "/home/hogan/Documents/hogan/logs/conf_files/4.conf";
Log::Log4perl::init($log_conf4);    #info
my $logger = Log::Log4perl->get_logger();
$logger->info("$0");

# weston, OH 41.37,-83.65
my $lat  = 41.37;
my $long = -83.65;

# the API docs says you must identify yourself, please make this somet
+hing legit
my $name = '(example.com, contact@example.com)';

my $url2 =
"https://nationalmap.gov/epqs/pqs.php?output=json&units=Meters&x=$lat&
+y=$long";
my $ub = Mojo::UserAgent->new;
$ub->transactor->name($name);

# get JSON response
my $qv = $ub->get($url2)->res->json;
$logger->info( dumper $qv);

my $elev = .208;    # 676 ft = .206 +.02 for observer  #km
$logger->info("$lat $long $elev");

my $url1 = "https://api.weather.gov/points/$lat,$long";
$logger->info("==============");
$logger->info($url1);

my $ua = Mojo::UserAgent->new;
$ua->transactor->name($name);

# get JSON response
my $pv      = $ua->get($url1)->res->json->{properties};
my $station = $pv->{'cwa'};
my $gridX   = $pv->{'gridX'};
my $gridY   = $pv->{'gridY'};
$logger->info("$station");
$logger->info("$gridX  $gridY");

$logger->info("==============");

## new transaction
## find elevation 

my $uc = Mojo::UserAgent->new;
$uc->transactor->name($name);
my $url3 = "https://api.weather.gov/gridpoints/$station/$gridX,$gridY"
+;
$logger->info( $url3 );
my $json = $uc->get($url3)->res->json;
#my $props = $json->{properties};
my $elev2 = $json->{properties}->{elevation}->{value};
my $unit = $json->{properties}->{elevation}->{unitCode};
$logger->info("==============");
#$logger->info(dumper($props));
$logger->info( $elev2 . ' '. $unit);

__END__
[download]

It takes me time fiddling with these things with perl and jq in order to get my head around them.

Q1) How do I get a valid value for the usgs query in lexical perl?

Thanks again for your post,