how to use php to get a number from a graph

[wiredChamber]

I would like to be able to get a number from this graph (it's for a river's flow) and use it in an if/else statement to make a light turn off or on using images.

For example, using php to check if the number is between 950 and 1100.

If someone could point me in the right tags to use, or a resource I could use to figure this out, it would be much appreciated.

[bradgrafelman]

I would say use the CSV form of the data instead (e.g. this) and simply use [man]fgetcsv/man to parse the data and do whatever you'd like.

[wiredChamber]

Thanks for the quick reply! Is there a place that can be used to search for these on usgs?

[bradgrafelman]

You mean like this ?

[wiredChamber]

More like this, and taking the most current cubic feet per second flow rate. Will fopen and fgetcsv still work for that?

[bradgrafelman]

wiredChamber wrote:

Will fopen and fgetcsv still work for that?

With the HTML format? No, because an HTML document is not a CSV document. Switch to the tab-separated version and then you can use [man]fgetcsv/man.

[wiredChamber]

 
<?php

$handle = fopen("http://waterdata.usgs.gov/nwis/uv?cb_00060=on&cb_00065=on&format=rbd&period=1&site_no=11516503","r");

while(($data = fgetcsv($handle, 5000," ")) !== FALSE) {
	echo "<pre>";
	print_r($data);
	echo "<pre>;
	}

?>

Error came back as:
Parse error: parse error, expecting T_VARIABLE' orT_DOLLAR_OPEN_CURLY_BRACES' or `T_CURLY_OPEN' in C:\wamp\www\php_sandbox\getdata.php on line 11

I've been trying using this tutorial
Is there a better place to get tutorials?

[dagon]

missing double quote and that second pre is missing a /

[wiredChamber]

<?php

$handle = fopen("http://waterdata.usgs.gov/nwis/uv?cb_00060=on&cb_00065=on&format=rbd&period=1&site_no=11516503","r");

while(($data = fgetcsv($handle, 5000," ")) !== FALSE) {
	//echo "<pre>";
	//print_r($data);
	//echo "<pre>;
	echo $data[0];	      

	echo "</br>";
	}

?>

This seems to work, but gives me two 1-character wide drop down lists.

How can I find the slot for cubic feet per second?

If I ask for it to echo anything over $data[0], php tells me:
Notice: Undefined offset: 1 in C:\wamp\www\php_sandbox\getdata.php on line 9

[wiredChamber]

dagon;10954897 wrote:

missing double quote and that second pre is missing a /

Thank you, that fixed that! And now I can see all of the arrays, but I don't know how to find the one that contains the information on cubic feet per second.

[zypher11]

Do you know of any XML format documents that display this data? if so that would make it infinitely easier for you to manipulate.

[wiredChamber]

zypher11;10954914 wrote:

Do you know of any XML format documents that display this data? if so that would make it infinitely easier for you to manipulate.

None that I know of, sorry 🙁

[bradgrafelman]

It doesn't get much easier than using [man]fgetcsv/man to parse the document into columns, really.

wiredChamber wrote:

How can I find the slot for cubic feet per second?

Look at the data ([man]print_r/man is useful for displaying arrays in a readable format, assuming you either use <pre>..</pre> tags or just view the source of the page in your browser) and reference whatever column(s) you want. In your loop above, you only echo'd out the first column.

EDIT: Also note that your use of [man]fgetcsv/man is incorrect above; you specified a space as the delimiter, when the webpage clearly says (and displays) data in a "tab-separated" format.

EDIT2: You also appear to have transposed the last two numbers in the URL in your sample code above, resulting in an error page ("No site found.").

[wiredChamber]

Thanks, fixed the problems with the delimiter and switching 03 to 30. Still, when I use this:

<?php

$handle = fopen("http://waterdata.usgs.gov/nwis/uv?cb_00060=on&cb_00065=on&format=rbd&period=1&site_no=11516530","r");

while(($data = fgetcsv($handle, 5000,"	")) !== FALSE) {
	 echo "<pre>";
	 print_r($data);
	 echo "</pre>";
	}

?>

I still cannot find the number that I'm looking for within the arrays (1060).

[bradgrafelman]

Paste the URL into your browser, you'll see why (you've again transposed two characters).

wiredChamber wrote:

Thanks, fixed the problems with the delimiter

Er... no you haven't. :p For the delimiter, you now have a string with four spaces, rather than a tab character (or the \t escape sequence to represent a tab character).