Over the weekend, the diverter in the spray head in our kitchen faucet gave up the ghost, so this morning, I took it to The Powder Room, where I’d bought it in 2008, in hopes that they could help me. They tried, but couldn’t fix it. A new one would cost $200, but they said that the manufacturer, Grohe, would send out a replacement under warranty if I called them.

Saving $200 sounded like a good idea, so I called as soon as I got home. After navigating the menu tree (only three keypresses required), I was greeted with the dreaded “wait times are longer than normal, please hold” recording. The hold music wasn’t too bad, and the announcements weren’t too annoying, but I was happy when the music stopped after about 4 minutes. And I was unhappy 2 seconds later when the recording restarted from the beginning.

An hour later, I had to hang up the phone to go to the dentist for a cleaning. And an examination. And the news that I had to have a filling redone (for free!), plus another filling and a new crown. I made the appointments and drove home to get back on the phone with Grohe.

An hour and another dozen repetitions of the recording later, an agent answered, and five minutes later, a new spray head was on its way to me. Well, not really – it’s out of stock but they expect to ship it around the 27th of this month.

We got our County Voter Information Guides and sample ballots today. Still to come: the State Voter Information Guide and the actual ballots. I can’t wait!

I created yesterday’s entry entirely on the iPad (except for the photo of the iPad, of course, which I took on the iPhone); I even used the WordPress app to upload the photo and entry to my blog. It was a bit clunkier than doing the work on the Mac and using the web interface to WordPress, but it wasn’t bad at all.

Soon after I uploaded the entry, though, I realized that I hadn’t removed the GPS coordinates from the photo – and that meant our house’s location was out in the world for anyone to harvest! I’m sure it’s not all that difficult to find out where we live anyway, but there’s no sense in publishing it unnecessarily.

I was stubborn and still didn’t want to use the Mac, so I figured out how to create an iOS Shortcut to strip the metadata and reposted last night’s photo, but I had to delete all the metadata, and it was a manual process – both of which seemed like a mistake.

What I really wanted was a way to automatically strip the GPS data from photos as I uploaded them to WordPress, but only if they were taken fairly close to our house. I didn’t find any plugins that seemed to fit the bill, so I started writing one.

This, of course, meant that I’d have to do the job in PHP, a language I’ve never used. But PHP is close enough in spirit to Python that it wasn’t too hard to suss out what I needed to do; it helped that PHP has native support for reading EXIF data in images.

#!/usr/bin/env php 
<?php
if ($argc >= 2) {
  $target = $argv[1];
}
else {
  $target = "IMG_6671.jpg";
}

function dist_between($lat1, $long1, $lat2, $long2) {
    // Computes distance in kilometers between two points using the haversine formula
    // Points are given in decimal degrees
    $l1 = $lat1 * M_PI / 180;
    $l2 = $lat2 * M_PI / 180;
    $deltaLat = ($lat2 - $lat1) * M_PI / 180;
    $deltaLong = ($long2 - $long1) * M_PI / 180;
    $a = (sin($deltaLat/2) ** 2) + cos($l1) * cos($l2) * (sin($deltaLong/2)**2);
    $c = 2 * atan2(sqrt($a), sqrt(1-$a));
    $d = 6371 * $c;
    return($d);
}

function evaluate_rational($rational) {
  $item = explode('/', $rational);
  return (float)$item[0] / (float)$item[1];
  }

function convert_location($location, $ref) {
  $loc = evaluate_rational($location[0]) + 
         evaluate_rational($location[1]) / 60.0 +
         evaluate_rational($location[2]) / 3600.0;
  if ($ref == 'S' or $ref == 's' or $ref == 'W' or $ref == 'w') {
    $mult = -1;
  } else {
    $mult = 1;
  }
  return $mult * $loc;
} 

$exif = exif_read_data($target);
if ((array_key_exists('GPSLatitudeRef', $exif)) and
    (array_key_exists('GPSLongitudeRef', $exif)) and 
    (array_key_exists('GPSLatitude', $exif)) and
    (array_key_exists('GPSLongitude', $exif))) {

  // Let's pick up the information.
  $lat = convert_location($exif['GPSLatitude'], $exif['GPSLatitudeRef']);
  $long = convert_location($exif['GPSLongitude'], $exif['GPSLongitudeRef']);
  
  // Home is a constant here, though it shouldn't be.
  $hlat = 38.8976633;
  $hlong = -77.0365739;
  
  // and so is the critical distance: 0.5km;
  $cdist = 0.5;
  
  // get the distance between home and the photo, and if it's less than the critical distance, wipe GPS.
  $dist = dist_between($lat, $long, $hlat, $hlong);
  if ($dist <= $cdist) {
      echo $target, " delete ", $dist, " is less than ", $cdist, PHP_EOL; 

      $cmd = "exiftool '-gps*=' " . $target;
      echo $cmd, PHP_EOL;
      exec($cmd, $output);
      foreach($output as $row) {
          echo $row, PHP_EOL;
      }
/*
  } else {
      echo "Not deleting ", $dist, " is more than ", $cdist, PHP_EOL;
 */
  }
  
}

?>

The observant among you will notice a few things about this code:

• It is not a WordPress plug-in
• It has hard-coded values for“home” and the radius of “nearby”
• It is undoubtedly VERY VERY bad PHP

However, it worked – I was able to use it against my existing WordPress media directory to strip the coordinates from about 10 images that I’d taken at home or within 500 meters of home.

The next step is to turn the code into a plugin so that I don’t have to think about it any more. But that’s for later this week.