Basics of Photography - ISO

ISO stands for International Standards Organisation. In the case of photography, it refers to the industry norm for sensitivity of emulsion based film. In the case of digital photography, ISO indicates a digital camera sensors sensitivity to light.

The higher the sensitivity, the less light is needed to make an exposure. So, shooting at a higher ISO value requires less light than shooting at a lower ISO value.

Read GPS data from Photographs using PHP

Modern cameras equipped with GPS receivers add the GPS coordinates to every photographs it takes. Using this data, the exact location where the photograph was taken can be determined. This information can be very useful when archiving or organizing the photographs. The GPS data will be embedded in the photo along with the EXIF header. In this post I will show you how to extract this information and convert it to some meaningful data using PHP.

Convert Latitude and Longitude From Degrees Minutes Seconds format to Decimal

Latitudes and Longitudes are mostly represented in the DMS (Degrees Minutes Seconds) format but for many applications, you need the values in decimal format. The decimal values can be easily stored and retrieved from database compared to DMS format. For creating maps using applications like Google Maps, it would be quite simple if you have those values in decimal format. In this post, the steps involved in this conversion are described.

Understanding Latitudes and Longitudes

You might have come across these terms in may be your 8th grade science class or sometimes even earlier. If you are looking for some short refreshment course then go ahead.
Any location on Earth can be described by two numbers, its latitude and its longitude. These are two angles, measured in degrees, minutes and seconds. These are denoted by the symbols ( °,   ',   "  ) e.g. 33° 21' 16" means an angle of 33 degrees, 21 minutes and 16 seconds. A degree contains 60 minutes of arc and a minute contains 60 seconds of arc. You may omit the words "of arc" where the context makes it absolutely clear that these are not units of time. Now lets see how these values are measured.

Maximum execution time exceeded - Error in PHP

You might have come across a Fatal error stating Maximum execution time of 30 seconds exceeded when running time consuming PHP scripts. Well, PHP sets its default maximum execution time for a script to 30 seconds so that the server is not overloaded running long scripts. But there are times when you need to run some time consuming scripts that does some database maintenance or processing large amounts of data. In such cases you are likely to exceed the 30 seconds time limit. PHP has a built in function set_time_limit which can be used to change the maximum execution time.

World IPv6 Launch - 6 June 2012

The World IPv6 Launch on 6 June 2012 is organized by the Internet Society and is intended to motivate organizations across the industry including Internet service providers (ISPs), hardware makers and web companies to prepare for and permanently enable Internet Protocol version 6 (IPv6) on their products and services. This initiative is to make sure that the internet can keep growing at its current rate or even more as the Internet Protocol version 4 (IPv4) address space runs out. World IPv6 Launch will mark the largest industry commitment to and deployment of IPv6 in the history of the Internet, with ISPs, home networking equipment manufacturers and web companies around the world permanently enabling IPv6 within their products and services.

Characteristics of a Network

Every network is characterized by a set of properties or factors that determines the usability of the network. These characteristics may be imposed due to hardware limitations or due to the implementation technique used. The seven major characteristics of a network are described here.

User Applications and Network - Balancing Point

There are plenty of applications that rely on a network for its operation. Applications can effect network performance and, conversely network performance can effect applications. So a careful prioritization has to be implemented so as to maintain a perfect balance between user experience and running cost.

Physical Components of a Network

A network is a collection of interconnected devices and end systems such as computers, servers etc which can communicate with each other. Networks can be found in different types of environments such as home, small office or large enterprises. Every network is composed of a few essential components which are described here.

Geolocation in HTML5

HTML5 has added plenty of resources that enhances the web browsing experience of its users. As a web developer, the point to note is that implementing these features on your site is much easier compared to what it has to offer. In this post, I will introduce you to Geolocation, a feature with which you can obtain the position in coordinates of a user.

Replace default Blogger Title With Post Title

You might have noticed that the default title for your blogger pages is the name of your blog itself. The disadvantage of using the default settings is that you will see the same title for all your posts. So if a user bookmarks any of your posts, he will see the blog name as the bookmark instead of the post title. This can also have a negative impact on search results as priority will be given to your blog name rather than what you post. You can easily modify the template to make the title change dynamically according to your posts, which is explained in this post.

Import CSV file to a Database using PHP

A CSV file, as the name suggests, contains a list of values separated by comma. The end of each row is marked by a line break. This is one of the oldest file format used in computers and hence is supported in almost all operating systems. In this post, I will describe how to use a CSV file to populate a MySQL database.

Check if Remote File Exists using PHP

You can easily check if a file exists using the PHP function file_exists(), but this function is limited to files within the same server. It will not work if you specify a location on a different domain. In that case you might want to use functions like file_get_contents(). Using these functions will download the whole file just to make sure that the file exists. This will take time and consume more memory. But this might not be what you want. You might just want to check if the file exists and not download it. In this post I have included a function with which you can do exactly the same.

INSERT IGNORE in MySQL

When you try to insert a new record in MySQL and the primary key specified in the insert query already exists, then an error will occur and the query will be aborted. Using the "IGNORE" keyword prevents errors from occurring. The records containing duplicate primary keys are ignored and the rest of the records are added. In the former case, no record will be inserted if such an error occurs.

Use PHP with MySQL

The main reason for many web developers to learn a scripting language like PHP is because of the ease with which it can interact with databases. In this post I will show you how to use PHP and the MySQL database to store information on the web and include it into your website. Before you read this tutorial you should have at least a basic knowledge of how to use PHP.