Re: Accessing elements directly

[Martin G. <gim...@gi...>]

"Tom Grant" <Tom...@LA...> writes:

> I currently have v 1.6x setup at:
> http://codeworks.org/phpweather/dtn.php displaying a table with 12
> airports from our local area (within a couple of hundred miles). It
> currently gives an error if the cloud array is empty.
>=20
> I've decided to make it work with the new version...

Cool!
=20
> Here's my test code for accessing array elements directly. I used as
> a base a reply to a question on this list from back in March.
>=20
> Apparently the get_metar_value function doesn't exist anymore. Has
> it been replaced?

No, it's hiding in the output/pw_text.php file... But there's no real
reason to use that function instead of just accessing the array
yourself - the following pieces of code to exactly the same:

<?php
$weather =3D new phpweather();
$data =3D $weather->decode_metar();

$temp =3D $data['temperature']['temp_c'];
$hum =3D  $data['rel_humidity'];
?>

<?php
$weather =3D new phpweather();
$text =3D new pw_text($weather);

$temp =3D $text->get_metar_value('temperature', 'temp_c');
$hum  =3D $text->get_metar_value('rel_humidity');
?>

The get_metar_value method is just a wrapper around the associative
array returned by a call to decode_metar.

> Or, do I need to include some other files. I've searched through
> most of the files, but haven't been able to find it.

Hehe - I couldn't find it either until I used 'grep' recursively on
all the files :-)
=20
> All help is appreciated!
>=20
> Thanks!
>=20
> <?php
> error_reporting(E_ALL);
>=20
> require('./phpweather.php');
> require('./pw_utilities.php');
>=20
> $weather =3D new phpweather(array()); $weather->set_icao('KDTN');

The above line should be shortened into this:

 $weather =3D new phpweather(array('icao' =3D> 'KDTN'));

The array-argument is meant to be used when you know some values at
the time you construct the object.
=20
> $language =3D "en";
>=20
> include(PHPWEATHER_BASE_DIR . "/output/pw_text_$language.php");
> $type =3D 'pw_text_' . $language;
> $text =3D new $type($weather, array());

It's no longer necessary to use array() as a second argument it's the
default value.

Since you're fiddling with the raw data returned by decode_metar,
you'll probably be interested in this:

The Raw Data
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

It's easy for you to get hold of the raw data produced by the code in
`phpweather.php':

     $weather =3D new phpweather();
     $data =3D $weather->decode_metar();

   The variable `$data' is now an multidimensional associative array
filled with all the information that the `decode_metar' function was
able to extract from the METAR. The different parts in the METAR is
stored under specific keys in the array -- if the METAR lacks a given
part, then the corresponding entry in the array will be left out. This
means, that you'll have to check each entry with `empty' before you use
it, otherwise you see warnings from PHP, if you've set the error
reporting level high enough.

   The following entries is always part of a METAR report, and is
therefore always part of the decoded METAR array:

`type'
     This can either be `METAR' or `SPECI' and denotes the type of the
     report. This isn't used for anything.

`metar'
     The raw METAR report.

`icao'
     The ICAO of the station which made the report.

`location'
     The English name of the station.

`time'
     A UNIX timestamp corresponding to the time of the report.

   The following entries are optional:

`report_mod'
     A report modifier which gives information about how the report was
     made: `AUTO' for a fully automated report with no human
     intervention or `COR' for a corrected report. It's supposed to be
     part of all METARs, but experience shows that it's not.

`wind'
     This is an array with information about the wind. The `deg' entry
     tells you the direction of the wind as compass-direction. If the
     wind came from variable directions, then will be the string `VRB'.

     The `meters_per_second', `miles_per_hour', and `knots' entries
     tells you the wind speed in various units.

     If gust was observer, there will be three extra entries:
     `gust_meters_per_second', `gust_miles_per_hour', and `gust_knots'.

     If the wind was varying, then two extra entries are present:
     `var_beg' and `var_end'. Both of these entries contain a
     compass-direction

`visibility'
     This is an array with visibility information. Each entry in the
     array is a separate visibility group.

     Each visibility group contains a `prefix' which can be `-1', `0',
     or `1' which tells you if the visibility reported is "less than",
     "normal", or "greater than" respectively.

     The visibility itself is stored in the `meter', `km', `ft', and
     `miles' entries. There is an optional entry `dir' for a direction
     -- if there's no direction, then the visibility refers to the
     overall visibility.

`runway'
     This is an array of runway groups. Each entry is a separate group.

     The groups contain an `nr' entry and an optional `approach' entry
     which tells you the runway-number and the approach respectively.
     The approach is one of `L', `C', or `R' for "left", "center", or
     "right" respectively.

     The visibility information can either be a single value or a pair
     of values in case of varying conditions. If there's only a single
     value, then `meter' and `ft' holds the visibility, an optional
     `prefix' can be `-1' if range is less than the lowest reportable
     value or `1' if greater than the greatest reportable value. A
     `tendency' entry holds either `D', `N' or `U' for "downward
     tendency", "no distinct tendency", or "upward tendency"
     respectively.

`weather'
     This holds the current weather phenomena and is one of the most
     interesting groups. It's an array of weather groups.

     Each group contains a `proximity' entry which can be either `VC'
     for phenomena in the vicinity or the empty string otherwise.

     Next comes the `intensity'. This can be `-' for light phenomena,
     the empty string for moderate phenomena, or `+' for heavy
     phenomena.

     This is followed by a `descriptor', a `precipitation', a
     `obscuration', and finally a `other' entry. These entries contain
     the actual data found in the METAR. This means that it's up to the
     application to decode these symbols further, so that `RA' becomes
     "rain" and so on.

`clouds'
     This is an array of cloud groups. Each group has a `condition'
     entry which can be either `CAVOK' for no clouds and no significant
     weather, `VV' for "vertical visibility", `FEW' for "few clouds",
     `SCT' for "scattered clouds", `BKN' for "broken clouds", `OVC' for
     "overcast", and `SKC' and `CLR' for "clear sky". The condition
     `CAVOK' is a bit special, because if it's present, then the
     `condition' entry will be the only entry in the cloud group.

     The other conditions will be part of a larger array with an
     optional `cumulus' entry denoting the presence of cumulonimbus
     (`CB') or towering cumulus (`TCU') clouds. There will also be
     `meter' and `ft' entries with the height of the clouds. If the
     clouds are below the station, then the height will be stored as
     `nil'. Theres an optional `prefix' with the usual meaning.

`temperature'
     This is the temperature group. It's an array with two or four
     entries: `temp_c' and `temp_f' is always present and is the
     temperature in degrees Celsius and Fahrenheit respectively. If
     information about the dew-point is present, then `dew_c' and
     `dew_f' will be added to the array.

`temp_min_max'
     Some stations report the minimum and maximum temperature over
     various timescales. The temperatures are stored in `min6h_c',
     `min6h_f', `max6h_c' and `max6h_f' for the temperatures in the
     last 6 hours, and in `min24h_c', `min24h_f', `max24h_c' and
     `max24h_f' for the temperatures in the last 24 hours.

`altimeter'
     This is the air pressure measured in various units. The array has
     these entries: `inhg', `mmhg', `hpa', and `atm'.

`precipitation'
     This is an array which stores the precipitation measured over
     various timescales. The entries `mm' and `in' contains the
     precipitation during the last hour, entries `mm_h6' and `in_6h'
     store the amount of precipitation in the last 3-6 hours and
     finally there's `mm_24h' and `in_24h' with the precipitation
     measured over the last 24 hours. If there has been snowfall, then
     that will be reported in the `snow_mm' and `snow_in' entries.

     All the entries can contain the special value `-1' which means
     that there was only a trace of precipitation.

`remarks'
     Anything which isn't recognized is added to this entry.

=2D-=20
Martin Geisler                       My GnuPG Key: 0xF7F6B57B

See my homepage at http://www.gimpster.com/ for:
PHP Weather =3D> Shows the current weather on your webpage.
PHP Shell   =3D> A telnet-connection (almost :-) in a PHP page.