Meteorology - Current Weather And Forecast Observations

Meteorology - Current Weather And Forecast Observations

" Since its creation, the human being adapts its life to weather conditions or 'weather troubles'.

Probably since then there is a desire that weather events are brought under control or prediction.

I guess that from such desire in the course of development of our civilization, emerged the idea

of creation the science known today under the name of Meteorology and later development of different

technologies for study, prediction and possibly control of the weather events. Regardless of the achieved level

of the development of all scientific disciplines and technologies used for the study of meteorological events,

there has not yet been made a one hundred percent accurate weather forecast or the announcement of meteorological events.

In accordance with that, every form of announcements of meteorological events should be accepted with reserve. "

Author Željko Perić

If you are interested in a scientific discipline called Meteorology, and all that it involves, refer to the articles at the following addresses

Wikipedia the free enciklopedia ( https://en.wikipedia.org/wiki/Meteorology )

Republic Hydrometeorological Service of Serbia ( http://www.hidmet.gov.rs/eng/meteorologija )

World Meteorological Organisation ( http://public.wmo.int/en )

Program 'Current Weather&Forecast Observations'

Program is designed to download and display specific meteorological data from a remote server. It is a brief description of current weather conditions and measured temperatures for selected location that is determined by its longitude and latitude, as well as data about the weather forecast for the next few days, a brief description of anticipated weather conditions and the predicted minimum and maximum daily temperatures.

Data are stored on a remote Internet server, which is accessible trough hyper text transfer protocol (HTTP). Using this protocol, connection to the server is estabilished and the request is placed for the specific data. Adequate applications on the server, processes the request and returns the desired information within a document, which is in standard, generally accepted, format (CSV, XML, JSON). The obtained data are processed and displayed in a format that is understandable to the user.

World Weather Online

The chart of the average percentual accuracy of the announcements of meteorological events for a period of four days

* Period of control of four-day weather forecast accuracy of the above companies was only one month.

When You have selected one of many companies, and formed HTTP request, 'endpoint', with a request for specific data, advance to writing program code.

Here is an example of program in the programming language C # 4.0, with the necessary .Net framework 4.0, and refers to the connection and download of the required weather data from YAHOO! Weather servers.

The basis for access to a remote server using HTTP queries make HttpWebRequest class for the formation of queries and

HttpWebResponse for connection and acceptance of response from the server, System.Net Namespace.

void Yahoo_Current_Weather()

{

string Yahoo_Server_Adress = "http://query.yahooapis.com/";

string YQL_Query = "v1/public/yql?q=select%20item.yweather:condition%20" +

"from%20weather.forecast%20where%20woeid%20in%20" +

"(select%20woeid%20from%20geo.places(1)%20where%20" +

"text%3D%22(44.66%2C20.93)%22)%20and%20u%20%3D%22c%22" +

"&format=json&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys";

string Document = string.Empty;

// Forms HTTP request

HttpWebRequest query = (HttpWebRequest) WebRequest.Create(Yahoo_Server_Adress + YQL_Query);

// Connect to the server and make request for informations

// Declaration of a variable "response", type of HttpWebResponse

// must be derived from HttpWebRequest.GetResponse () instance

HttpWebResponse response = (HttpWebResponse) query.GetResponse();

// Create a variable "data", type of Stream and

// transfers the requested data from the

// instance of variable "response" type of Stream

Stream data = response.GetResponseStream();

// Create a variable "reader" to access data

StreamReader reader = new StreamReader(data,Encoding.UTF8);

// Read all the data and transfer them to the variable 'Document'

Document = reader.ReadToEnd();

// Save data to a text file

File.WriteAllText("YahooCurrentWeather.txt",Document,Encoding.UTF8);

// Closes and frees up all resources

// that occupies the variable 'reader'

reader.Close ();

reader.Dispose();

// Closes and frees up all resources

// that occupies the variable 'data'

data.Close ();

data.Dispose();

// Closes and frees up resources that occupies the variable 'response'

// Frees connection to the Internet for reuse

response.Close ();

}

When the method or subroutine 'void Yahoo_Current_Weather ()' executes, all the data that YAHOO! Weather server forwarded to your computer, were first placed in the variable 'Document' type of string, and then recorded in the file "YahooCurrentWeather.txt" in UTF8 Format which allows you to work with the Cyrillic alphabet.

If you do not want to, recording data is not necessary. This would also be a template for the connection and the realization of HTTP request to a remote server.

What has not been done is Try / Cach structure in order to prevent the violent interruption of program execution if the connection with server is interrupted or there is a redirection from the requested address to another server or application server can not process the request for information ...

Now you need to access the meteorological data that are formated like this, when JSON format of the document is in the question:

{

"query":

{

"count":1,

"created":"2014-11-22T19:33:24Z",

"lang":"en-US",

"results":

{

"channel":

{

"item":

{

"condition":

{

"code":"27",

"date":"Sat, 22 Nov 2014 7:00 pm CET",

"temp":"6",

"text":"Mostly Cloudy"

}

}

}

}

}

}

The figure shows the structure of the text within a text document with the names of variables and their values. This arrangement was made by an author to improve the readability. If the data was observed as how they are stored within the document, it would look like this, all the data in one line:

{"query":{"count":1,"created":"2014-11-22T21:20:51Z","lang":"en-US","results":{"channel":{"item":{"condition":{"code":"27","date":"Sat, 22 Nov 2014 7:00 pm CET","temp":"6","text":"Mostly Cloudy"}}}}}}

Date and time of creation of the document string created = "2014-11-22T19: 33: 24Z"

Code of the Image which represents the weather description string code = "27"

Date and time of last weather data update string date = "Sat, 22 Nov 2014 7:00 pm CET"

Current temperature string temp = "6"

A brief description of the weather conditions string text = "Mostly Cloudy"

Access to the values of variables can be done by deserialization data in the JSON document, which is done as shown on the following address

Microsoft MSDN ( http://msdn.microsoft.com/en-us/library/bb412179%28v=vs.110%29.aspx ),

or to get the necessary values by a simple search trough text of the document by keyword, name of the variable, and direct reading of the variable value, what was done in the program, by using the method ' Search_Result Find_Text(string Dokument, string Text, int Position) ', which returns a ' Search_Result ' class- type object with two instances, the variable value and location.

class Search_Result

{

public string value = string.Empty;

public int position = 0;

}

Search_Result Find_Text(string Dokument, string Text, int Position)

{

// Variable Document contains text from JSON document

// Variable Text contains search keyword

// If we need Image code value, the key word for search should be

//

// "code":"

//

// quotation marks included

// Variable Position contains letter position inside the text from which method starts search

Search_Result result = new Search_Result();

int document_length = 0;

int text_length = 0;

int letter_position = 0;

document_length = Dokument.Length;

text_length = Text.Length;

letter_position = Position;

while(letter_position<document_length-text_length)

{

if(Dokument.Substring(letter_position,text_length) == Text)

{

letter_position+=text_length;

break;

}

else

{

letter_position++;

}

}

while(Dokument[letter_position] != '"')

{

result.value += Dokument[letter_position];

letter_position++;

}

result.position = letter_position;

return result;

// Returns the value of the variable and the letter position inside the text

// where the value ends, due to the successive search

}

When you find and read the values of variables inside the JSON document, perform their presentation to the user via the user interface of the program.

Finally thoroughly review the ' Terms & Conditions ' of service, so that selected company do not prohibit the use of it to You, because for breaking it.

A program that can be downloaded by clicking on any image or the link below, requires .Net 4.0 framevork ( ^ ),

and high-quality Internet connection. Given that it is forbidden to use someone else's access key to get the access to the meteorological data,

you will need to obtain Your own key codes to use the program in full and unimpeded access to the data.

All the best,

Author.