Web Data Extraction

The Internet as we know today is a repository of information that can be accessed across geographical societies. In just over two decades, the Web has moved from a university curiosity to a fundamental research, marketing and communications vehicle that impinges upon the everyday life of most people in all over the world. It is accessed by over 16% of the population of the world spanning over 233 countries.

As the amount of information on the Web grows, that information becomes ever harder to keep track of and use. Compounding the matter is this information is spread over billions of Web pages, each with its own independent structure and format. So how do you find the information you're looking for in a useful format - and do it quickly and easily without breaking the bank?

Search Isn't Enough

Search engines are a big help, but they can do only part of the work, and they are hard-pressed to keep up with daily changes. For all the power of Google and its kin, all that search engines can do is locate information and point to it. They go only two or three levels deep into a Web site to find information and then return URLs. Search Engines cannot retrieve information from deep-web, information that is available only after filling in some sort of registration form and logging, and store it in a desirable format. In order to save the information in a desirable format or a particular application, after using the search engine to locate data, you still have to do the following tasks to capture the information you need:

· Scan the content until you find the information.

· Mark the information (usually by highlighting with a mouse).

· Switch to another application (such as a spreadsheet, database or word processor).

· Paste the information into that application.

Its not all copy and paste

Consider the scenario of a company is looking to build up an email marketing list of over 100,000 thousand names and email addresses from a public group. It will take up over 28 man-hours if the person manages to copy and paste the Name and Email in 1 second, translating to over $500 in wages only, not to mention the other costs associated with it. Time involved in copying a record is directly proportion to the number of fields of data that has to copy/pasted.

Is there any Alternative to copy-paste?

A better solution, especially for companies that are aiming to exploit a broad swath of data about markets or competitors available on the Internet, lies with usage of custom Web harvesting software and tools.

Web harvesting software automatically extracts information from the Web and picks up where search engines leave off, doing the work the search engine can't. Extraction tools automate the reading, the copying and pasting necessary to collect information for further use. The software mimics the human interaction with the website and gathers data in a manner as if the website is being browsed. Web Harvesting software only navigate the website to locate, filter and copy the required data at much higher speeds that is humanly possible. Advanced software even able to browse the website and gather data silently without leaving the footprints of access.

The next article of this series will give more details about how such softwares and uncover some myths on web harvesting.


Article Source: http://EzineArticles.com/expert/Thomas_Tuke/5484

How Easily Can You Extract Data From Web

With tech advancements taking the entire world by a storm, every sector is undergoing massive transformations. As far as the business arena is concerned, the rise of big data and data analytic is playing a crucial part in operations. Big data and data analysis is the best way to identify customer interests. Businesses can gain crystal clear insights into consumers’ preferences, choices, and purchase behaviours, and that’s what leads to unmatched business success. So, it’s here that we come across a crucial question. How do enterprises and organizations leverage data to gain crucial insights into consumer preferences? Well, data extraction and mining are the two significant processes in this context. Let’s take a look at what data extraction means as a process.

Decoding data extraction

Businesses across the globe are trying their best to retrieve crucial data. But, what is it that’s helping them do that? It’s here that the concept of data extraction comes into the picture. Let’s begin with a functional definition of this concept. According to formal definitions, ‘data extraction’ refers to the retrieval of crucial information through crawling and indexing. The sources of this extraction are mostly poorly-structured or unstructured data sets. Data extraction can prove to be highly beneficial if done in the right way. With the increasing shift towards online operations, extracting data from the web has become highly important.

The emergence of ‘scraping’

The act of information or data retrieval gets a unique name, and that’s what we call ‘data scraping.’ You might have already decided to pull data from 3rd party websites. If that’s what it is, then it’s high time to embark on the project. Most of the extractors will begin by checking the presence of APIs. However, they might be unaware of a crucial and unique option in this context.

Automatic data support

Every website lends virtual support to a structured data source, and that too by default. You can pull out or retrieve highly relevant data directly from the HTML. The process is termed as ‘web scraping’ and can ensure numerous benefits for you. Let’s check out how web scraping is useful and awesome.

Any content you view is ready for scraping

All of us download various stuff throughout the day. Whether it is music, important documents or images, downloads seem to be regular affairs. When you are successful in downloading any particular content of a page, it means the website offers unrestricted access to your browser. It won’t take long for you to understand that the content is programmatically accessible too. On that note, it’s high time to work out effective reasons that define the importance of web scraping. Before opting for RSS feeds, APIs, or other conventional data extraction methods, you should assess the benefits of web scraping. Here’s what you need to know in this context.

Website vs. APIs: Who’s the winner?

Site owners are more concerned about their public-facing or official websites than the structured data feeds. APIs can change, and feeds can shift without prior notifications. The breakdown of Twitter’s developer ecosystem is a crucial example for this.

So, what are the reasons for this downfall?

At times, these errors are deliberate. However, the crucial reasons are something else. Most of the enterprises are completely unaware of their structured data and information. Even if the data gets damaged, altered, or mangled, there’s no one to care about it.

However, that isn’t what happens with the website. When an official website stops functioning or delivers poor performance, the consequences are direct and in-your-face. Quite naturally, developers and site owners decide to fix it almost instantaneously.

Zero-rate limiting

Rate-limiting doesn’t exist for public websites. Although it’s imperative to build defences against access automation, most of the enterprises don’t care to do that. It’s only done if there are captchas on signups. If you aren’t making repeated requests, there are no possibilities of you being considered as a DDOS attack.

In-your-face data

Web scraping is perhaps the best way to gain access to crucial data. The desired data sets are already there, and you won’t have to rely on APIs or other data sources for gaining access. All you need to do is browse the site and find out the most appropriate data. Identifying and figuring out the basic data patterns will help you to a great extent.

Unknown and Anonymous access

You might want to gather information or collect data secretly. Simply put, you might wish to keep the entire process highly confidential. APIs will demand registrations and give you a key, which is the most important part of sending requests. With HTTP requests, you can stay secure and keep the process confidential, as the only aspects exposed are your site cookies and IP address. These are some of the reasons explaining the benefits of web scraping. Once you are through with these points, it’s high time to master the art of scraping.

Getting started with data extraction

If you are already eager to grab data, it’s high time you work on the blueprints for the project. Surprised? Well, data scraping or rather web data scraping requires in-depth analysis along with a bit of upfront work. While documentations are available with APIs, that’s not the case with HTTP requests. Be patient and innovative, as that will help you throughout the project.

2. Data fetching

Begin the process by looking for the URL and knowing the endpoints. Here are some of the pointers worth considering:

- Organized information: You must have an idea of the kind of information you want. If you wish to have it in an organized manner, rely on the navigation offered by the site. Track the changes in the site URL while you click through sections and sub-sections.
- Search functionality: Websites with search functionality will make your job easier than ever. You can keep on typing some of the useful terms or keywords based on your search. While doing so, keep track of URL changes.
- Removing unnecessary parameters: When it comes to looking for crucial information, the GET parameter plays a vital role. Try looking for unnecessary and undesired GET parameters in the URL, and removing them from the URL. Keep the ones that’ll help you load the data.

2. Pagination comes next

While looking for data, you might have to scroll down and move to subsequent pages. Once you click to Page 2, ‘offset=parameter’ gets added to the selected URL. Now, what is this function all about? The ‘offset=parameter’ function can represent either the number of features on the page or the page-numbering itself. The function will help you perform multiple iterations until you attain the “end of data” status.

Trying out AJAX

Most of the people nurture certain misconceptions about data scraping. While they think that AJAX makes their job tougher than ever, it’s actually the opposite. Sites utilising AJAX for data-loading ensures smooth data scraping. The time isn’t far away when AJAX will return along with JavaScript. Pulling up the ‘Network’ tab in Firebug or Web Inspector will be the best thing to do in this context. With these tips in mind, you will have the opportunity to get crucial data or information from the server. You need to extract the information and get it out of the page markup, which is the most difficult or tricky part of the process.

Unstructured data issues

When it comes to dealing with unstructured data, you will need to keep certain crucial aspects in mind. As stated earlier, pulling out the data from page markups is a highly critical task. Here’s how you can do it:

1. Utilising the CSS hooks

According to numerous web designers, the CSS hooks happen to be the best resources for puling data. Since it doesn’t involve numerous classes, CSS hooks offer straightforward data scraping.

2. Good HTML Parsing

Having a good HTML library will help you in ways more than one. With the help of a functional and dynamic HTML parsing library, you can create several iterations as and when you wish to.
Knowing the loopholes

Web scraping won’t be an easy affair. However, it won’t be a hard nut to crack either. While knowing the crucial web scraping tips is necessary, it’s also imperative to get an idea of the traps. If you have been thinking about it, we have something for you!

- Login contents: Contents that require you to login might prove to be potential traps. It reveals your identity and wreaks havoc on your project’s confidentiality.

- Rate limiting: Rate limiting can affect your scraping needs both positively and negatively, and that entirely depends on the application you are working on.

Source:-https://www.promptcloud.com/blog/how-easy-is-data-extraction

Data Collection - Make a Plan

Planning for the data collection activity provides a stable and reliable data collection process in the Measure phase.

A well-planned activity ensures that your efforts and costs will not be in vain. Data collection typically involves three phases: pre-collection, collection and post-collection.

Pre-collection activities: Goal setting and forming operational definitions are some of the pre-collection activities that form the basis for systematic and precise data collection.

1.  Setting goals and objectives: Goal setting and defining objectives is the most important part of the pre-collection phase.

It enables teams to give direction to the data to be collected. The plan includes description of the Six Sigma project being planned. It lists out specific data that is required for the further steps in the process.

If there are no specific details as to the data needs, the data collection activity will not be within scope - and may become irrelevant over a period of time.

The plan must mention the rationale of data being collected as well as the final utilization.

2.  Define operational definitions: The team must clearly define what and how data has to be collected. An operational definition of scope, time interval and the number of observations required is very important.

If it mentions the methodology to be used, it can act a very important guideline to all data collection team members.

An understanding of all applicable information can help ensure that there no misleading data is collected, which may be loosely interpreted leading to a disastrous outcome.

3.  Repeatability, stability and accuracy of data: The repeatability of the data being collected is very important.

This means that when the same operator undertakes that same activity on a later date, it should produce the same output. Additionally, it is reproducible if all operators reach the same outcome.

Measurement systems should be accurate and stable, such that outcomes are the same with similar equipment over a period of time.

The team may carry out testing to ensure that there is no reduction in these factors.

Collection Activity

After planning and defining goals, the actual data collection process starts according to plan. Going by the plan ensures that teams achieve expected results consistently and accurately.

Training can be undertaken so as to ensure that all data collection agents have a common understanding of data being collected. Black Belts or team leaders can look over the process initially to provide any support needed.

For data collection over a longer period, teams need to ensure regular oversight to ensure that no collection activities are overlooked.

Post collection activities

Once collection activities are completed, the accuracy and reliability of the data has to be reviewed.

Source: http://ezinearticles.com/?Data-Collection---Make-a-Plan&id=2792515