Also thanks to cURL, the webcams are on at danallen.com. To see the latest soon to be defunct programmers work area, click here. Thank you

Here is the code for how the Earth gets spinning:




$dogTargetPage = 'http://www.fourmilab.ch/cgi-bin/Earth?imgsize=275&opt=-l&lat=55.0&ns=North&lon=60&ew=West&alt=30000&img=learth.evif';

// create curl resource
$ch = curl_init();

// set url
curl_setopt($ch, CURLOPT_URL, $dogTargetPage);

//return the transfer as a string
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

// $output contains the output string
$output = curl_exec($ch);

// close curl resource to free up system resources
curl_close($ch);


$dogSniffNose = strpos($output,'img src="/cgi-bin/Earth?di=');
$dogPicAddressStart = $dogSniffNose + 27;
$dogSniffTail = strpos($output,'"', $dogPicAddressStart);
$dogPicAddressEnd = $dogSniffTail;
$dogPicAddressLength = $dogPicAddressEnd - $dogPicAddressStart;
$dogPicHash = substr($output,$dogPicAddressStart,$dogPicAddressLength);
$dogPicURL = 'http://www.fourmilab.ch/cgi-bin/Earth?di=' . $dogPicHash;
?>

Next steps:

1. Fix webcams that run with the spinning Earth at danallen.com DONE
2. Replace live image link from danallen.com with cron job that saves updated pic once per 15 minutes. DONE
3. Save those 15-minute pics for a year
4. Use pics from file instead of Swiss Observatory, to achieve spin independence
5. Be happy for being a step closer to fulfilling a dream

---

October 2009
The basic idea is to use cURL to read a webpage at the Swiss Earth Observatory, looking for the address of the earth image (sample), saving that address to a php variable that can then be used to display the latest live image on my website.

To see what CURL is going to do, surf over to the Swiss Earth Observatory. When you get there, right click in the white area of the page, and select VIEW SOURCE. This will display the web page code sent to your browser. The browser translates this code on your computer into the web page you see. The picture of Earth at that page has an address that always changes. To see what it is now, scan down the screen displayed by view source until you find

<img src="/cgi-bin/Earth?di=

After the di=, there will be a long string of letters and numbers, that look something like this.

E9B2DF0EAA864 48B20D6AB4ABD37D7605BB4A 684FEC0D8EB20EA5BAB710F335356 35B0DCF2B0D15E683658B6E75C4761D5C A004DFF5266CE5675B091

That long string always changes. Curl can read the SOURCE for the web page, find the long string, and save it.

Starting with an introduction from php.net

Once you've compiled PHP with cURL support (comes with Linux hosting from Godaddy), you can begin using the cURL functions.

The basic idea behind the cURL functions is that you initialize a cURL session using the curl_init(), then you can set all your options for the transfer via the curl_setopt(), then you can execute the session with the curl_exec() and then you finish off your session using the curl_close(). Here is an example that uses the cURL functions to fetch the example.com homepage into a file:

$ch = curl_init("http://www.example.com/");
$fp = fopen("example_homepage.txt", "w");

curl_setopt($ch, CURLOPT_FILE, $fp);
curl_setopt($ch, CURLOPT_HEADER, 0);

curl_exec($ch);
curl_close($ch);
fclose($fp);
?>