Computer Fundamentals Index

Computer Introduction Types of computer Characteristics of computer Uses of computer History of Computers

Computer Languages

Low Level language Middle level Language High level language

Computer Generation

Generation of Computers First Generation of Computer Second generation of Computers Third generation of Computers Fourth generation of Computers Fifth generation of Computers Sixth Generation of Computer

Peripheral Devices

Input devices Output device


Block diagram and basic components Control processing unit (CPU) Software Hardware


Computer Memory Registers Memory Hierarchy RAM Vs ROM Understanding file sizes (Bytes, KB, MB, GB, TB, PB, EB, ZB, YB)

Computer Network

Types of Network Types of Area Networks (LAN, WAN, MAN) TCP Flags

Computer Virus

Computer Virus

Computer Ports

Computer Ports


How to hack a computer How much do Computer Programmers make How does a Computer work How to associate a file with a program How does a computer convert text into binary How does a computer process data into information How to fix a CD-ROM DVD How to fix the no input signal How to install computer memory How to associate a file with a program How to log out of your operating system How do I change my name on Google How to installation or uninstallation Microsoft Paint How to fix a not a valid Win32 application error How to fix missing Microsoft Windows .dll files How to use a computer keyboard How to erase my hard drive and start over How can I test how many words I can write a minute How to shut down a computer How do I open and edit the Windows registry How to edit the registry from the command line How to restart Microsoft Windows How to install a computer processor How to open Microsoft Paint How to fix problems in Windows after installing new software How to enable or disable the preview pane of Microsoft Outlook How to open a Microsoft .wps or Works file in Word How to view the HTML source code in Microsoft Word How to View or Change the Screen Resolution of a Monitor How to Connect and Install a Computer Keyboard How to Delete Temporary Files in Windows 10 How to determine Which Version of Microsoft Office I'm using How to find out how much hard drive space is available How to Fix PC Stuck on Verifying DMI Pool Data How to choose which items show in the notification area How to find similar images using Search by Image How to fix Low Memory and out of memory errors How To Replace the CMOS Battery How do I Update my Antivirus Program How to fix a general protection fault How to Identify problems in the Windows Device Manager How can the Base be Shown How to test if a Website or Web Page is down How Much is 1 Byte, Kilobyte, Megabyte, Gigabyte, etc How to fix a CMOS checksum error How to Fix a Windows CD-ROM, DVD, or Disc Drive Issue How to Open Safe Mode How to Password Protect Files and Folders in Windows How to Reset CMOS or BIOS Settings How to use Computer Keyboard How to create a text file How to enable or disable DHCP in Windows How to test computer memory to determine if its bad How do double space or change line spacing in Microsoft Word How do I know if I have Windows Administrator Rights How many cores does my computer have How to Create a Directory or Folder How to Enter and Exit the BIOS or CMOS Setup How to change Windows Compatibility mode How to clear your internet browser history How to Connect Computer Speakers How to Copy a Web Page Link or URL How to install a Hard Drive or SSD How to Open the Windows Control Panel How to split a screen in Windows How to copy text from a scanned PDF


Who invented Computer What are the advantages of the Internet? What are the disadvantages of the Internet? Is my computer 64 bit? What is Edge Computing? What is a Router? What is Monitor What is Printer What is a Web Browser What is Microphone What is a Webcam What is PC What is Keyboard What is Motherboard What is WAP What is URL What is a Digital Assistant When was the first Computer Invented What is Modem What is Firmware What is Imperative Programming What is Protocol What is Safe Mode What is Device Driver What is Hybrid Topology What is Mesh Topology What is Procedural language What is a hyperlink What is a Username Who invented the Internet What is Video Card What is Sound Card What is Binary What does Alt+B do What does Alt+D do What does Alt+E do What does Alt+Esc do What does Alt+R do What does ALT + Q do What does Alt + Tab do What is Data Manipulation What is a touch screen What is Back Panel What is Analog Monitor What is AR lens What is an ATX Style Connector What is a File System What is Hard Disk Drive (HDD) What is a boot device What is accessibility What is Line In What is network Interface card (NIC) What is Optical Disk Where can I ask questions on the internet What is Auto Rotate What is CAD (Computer-aided design) What is Cable Modem What is Home Page What is boot menu What is braille reader What is flash memory What is Windows What is Clipboard What is Cyber Warfare What is Myspace Why has my IP address changed What is Jacquard Loom My computer is running slow, what steps can I do to fix it What is a Kensington Lock What is a multicore processor What is automation Are smartphones and tablets computers What is a Login Script What is a Loosely Typed Language What is Multitasking? Why my computer monitor shows no display or black screen What is REM What is Parallelization What is Overtype mode What is open with What is Bracket What is an Online Service What is REM What is Parallelization What is Overtype mode What is open with What is Bracket What is an Online Service What is the Pg Dn Key (Page Down Key) What is the Pg up Key (Page up Key) What is Palmtop Computer What is a Processing Device What is a Print Preview What is the Print Screen Key What can I do if my computer or laptop is lost or stolen What is a Model Number What are the currently available antivirus programs What are Toggle keys What is a Case fan What is a Silicon Chip What is a Slate PC What is a TAB stop What is an Octothorpe What is Task Pane What is Task View What is the svchost.exe file used for in Windows Where can I find free online virus scanners Why am I unable to increase the resolution in Windows What is Autofill When I click my mouse, it sometimes double-clicks What is Scratch What is UDIMM What is MsConfig What is an Expansion Card What is an Executable File What is an Elevated Command Prompt What is an AC Adapter What is AIMBOT What is a Software Suite What is a LED Monitor What does Alt + X do What does alt + space do What does Alt + O do Now that I’ve got a Computer, what can i do What is a Punch Card What is RDIMM What is Select All What is Serial number What is Thermos flask What programs can I use for speech recognition What are the Advantages of Computers What are the Disadvantages of Computers What does Alt + T do What Hardware Device Drivers should be Updated What is a Desktop What is a Ring Topology What is CMOS What is a Directory What is a Mechanical Mouse What is a Plotter What is a Variable What is an Icon What is Data What is HDMI What is Remote What is Right-Click What is SMPS Why does my Laptop not turn on What is a Copyright What is a Cordless Mouse What is a CSV file What is a Joystick What is a Start Button What is a Taskbar What is an Alignment What is an Output Device What is Cat 5 What is Google Chrome What is Post What are Recordable DVD Drives What Does Alt + F4 Do What Does Alt + L Do What is a bit (Binary Digit) What is a cable What is a Calculator What is a capacitor What is a Cold Boot What is a Dialog Box What is a Dual-boot What is a Slide What is A4 What is AM What is Barcode Reader What is EHCI What is a Header What is a Joystick What is a Secondary Storage Device What is Access Time What is Account Sharing What is an Asterisk What is Asynchronous DRAM What is Back Quote What is BIOS What is Borderless Printing What is Case Badge What is CD-ROM What is Chat Slang What is Composite What is RJ Cable What Are Bottom Row Keys What is SAN What is Tray What is VDU What Does Alt + M Do What Does Alt + P Do What is a Cell What is a Command Key What is a key Combination What is a Menu Bar What is a Startup What is a T What is Chat What are the F1 through F12 keys What does Alt + Enter do What Does Alt + Home DO What does Alt + R do What does Ctrl + B do What Does Ctrl + Enter Do What Does Ctrl + R Do What does Ctrl + G do What does Ctrl + 9 do What does Ctrl + End do What does Ctrl + O do What Does Ctrl + P do What Does Ctrl + Q do What is a Colon What is a Core What is Apple Touch Icon What is Clock What is Code What is Computer Crime What is Ctrl What is DAT What is Data diddling What is Date Why won't my computer turn on What Does Alt + N Do What does ctrl + 2 do What does ctrl + space do What does Ctrl + W do What does Ctrl + T Do What Does Ctrl + 2 do What does Ctrl + 5 Do What are the most common file types and file extensions What are Sticky keys What Does Ctrl + Shift + Esc Do What is Settings What is Task Manager What is Taskbar What is a DNS Resolver What does ctrl + 1 do What does ctrl + 0 do How to install software What is a Folder What is a Legend What is a MAC Address What is a Path What is a Ruler What is a Toolbar What is an Intranet Meaning and Differences with Internet What is an SSD What is Inheritance What is Tablet What is Depth What is Docking Station What is Double Click What is a Solid Ink Printer What is a Temporary File What is Backup and Restore What is Electronic Payment Systems Eps What is Marshalling


Difference between hardware and software Difference between multiprocessor and distributed systems Difference between Desktop and Laptop Difference between File and folder Difference between Hard Copy and Soft Copy Open Source Programs vs Closed Source Programs Difference between Optical Fibre and Coaxial Cable Difference between Website and Webpage Difference between Classes and Objects Input VS Output Difference between Primary and Secondary Storage with Examples


Quantum Computing Computer Software Autoexec.bat and config.sys info Update an Antivirus Use of Internet Advantages and disadvantages of Email Computing Power Internet Explorer Shortcut Keys Advanced Encryption Standard (AES) Augmented Reality Infrastructure Readiness Check Top 10 Internet tips and tricks Introduction and Features of FoxPro Features of Multimedia Top 10 online services and applications Receiving S.M.A.R.T. status bad backup and replacing error Version Control System Uninstalling Software or Apps in Windows Data Warehouse Increase or decrease font size in Word using keyboard shortcuts Mouse not detected or working in Windows Computer Cleaning Information and Steps Function Keys on Keyboard Windows 7 Alt+Tab won’t stay on top or stick 10 Essential Examples of Web Browsers Binary Subtraction using 2’s Complement Case Sensitive Languages Computer Pioneers and people who are CEO Microsoft Word Shortcut Keys Parts of Computers Names, Definitions and Images ROM and its Types Basics of Information Technology Characteristics of a Good Software Design Characteristics of Management Information System Classification of Management Information System Implementation of MIS Input Devices of Computer Definition Limitations of Management Information System 3 Types Of Network in Computer Block Diagram Of Control Unit Difference Between Computer and Embedded System Difference Between Hard Disk and Floppy Disk Abstraction in OOAD Hardware and Software Devices Optomechanical Mouse CMOS Memory What is a Terminal? What is Graphic Design? What is Load? What is Passcode? What is Reboot? What is Registry? What is Safe Mode? What is Standby? What is SYN (Synchronize)? What is Task Manager? Attribute Computing BPS in Computer Bulletin Board System Light Pen Input Device 3 TYPES OF NETWORK IN COMPUTER Block diagram of control unit What is a Solid Ink Printer? What is a Temporary File? What is an App launcher? What is Backup and Restore? What is a Tab Character? What is the Core i3? What is Paint? What is a Workbook? Advantages and Disadvantages of Online Education What is a String? What is a VDU (Visible Display Unit)? 50 Uses of Computer What is Workspace? What is a Procedural Language? What is VGA (Video Graphics Array)?

What is a Legend?

A legend is a key or guide used to help explain the meaning of symbols, colours, or other elements in a graphical representation, such as a map, chart, or graph. The term "legend" is often used interchangeably with "key," "caption," or "explanatory notes" and serves to help make information more accessible and easier to understand.

Legends can be found in various applications, from physical maps and charts to computer software and data visualization tools. They are often used to convey complex information or data visually and intuitively, making it easier for users to interpret and understand.

One of the easiest examples of a legend is a map legend. This type of legend is typically found on physical maps and provides information about the meaning of symbols, such as roads, bodies of water, and geographic features. For example, a map legend might include a symbol for a mountain range, along with a note explaining that the symbol represents a mountain range and indicating the elevation of the range in meters or feet.

In addition to physical maps, legends are also commonly used in digital mapping applications, such as Google Maps or Apple Maps. In these applications, the legend may be interactive, allowing users to toggle between different views or layers to see different types of information, such as traffic conditions, public transportation routes, or satellite imagery.

Another example of a legend can be found in charts and graphs. These legends typically provide information about the meaning of different colours, patterns, or shapes used to represent data. For example, in a line graph showing a city's population growth over time, the legend might include a line colour for each decade and a note explaining what each line represents.

What is a Legend

Legends in Scientific Data Visualization

Legends are also commonly used in scientific data visualization. For example, in a molecular model, a legend might indicate the meaning of different colours used to represent different types of atoms or different shapes used to represent different molecular structures.

In addition to helping users understand the meaning of symbols and colours, legends can provide context or additional information about a particular visualization. For example, in a bar chart comparing the sales of different products, the legend might include a note about the period represented or the geographic region covered by the data.

In some cases, legends can be interactive, allowing users to click on different legend elements to filter or highlight specific data points or categories. For example, in a scatter plot showing the relationship between two variables, the legend might include buttons to toggle between different data sets or to highlight specific data points based on their category.

Legends are essential for making complex information more accessible and easier to understand. Whether in maps, charts, graphs, or other forms of data visualization, legends provide users with the context and guidance they need to interpret and use data effectively.

What is a Legend

This is an example of a Legend used in a Graph.

Other Aspects of Legend

Legends are essential for maintaining consistency and accuracy in data visualization.

In addition to providing context and clarity for the reader, legends play an important role in maintaining consistency and accuracy in data visualization. In many cases, a legend is a reference for the complete visualization, ensuring that the symbols or colours used are consistent throughout.

For example, imagine a chart that shows the performance of different products over time, with each product represented by a different colour. With a legend, it may be easier for the reader to understand which colour represents which product or to compare the performance of different products accurately. Consistent use of colours or symbols can also lead to clarity and interpretation of the data.

By including a legend, data visualization designers can ensure that their visualizations are consistent and accurate and that the meaning of each element is communicated to the reader. In some cases, legends may also include information about the data source, the date range, or other important contextual information.

Legends can also convey additional information that may take time to be apparent in a visualization. For example, on a map, a legend may include information about the scale, orientation, or coordinate system used, which can be important for accurately interpreting the map. In a chart or graph, a legend may provide information about the units of measurement or the specific data points being represented.

Furthermore, legends can also be used to provide key information about the context or background of a visualization. For example, a legend on a graph or chart may include information about the data source, the methodology used to collect the data or the timeframe over which the data was collected. This information can be crucial for the reader to understand the significance and limitations of the data presented in the visualization.

Legends can also highlight specific elements within a visualization, such as outliers or points of interest. For example, in a scatter plot, a legend may highlight the data point representing the highest or lowest value or a point representing a significant event or change.

Finally, it's important to note that legends should be designed to be clear and concise, using appropriate terminology and symbols that the reader easily understands. They should also be placed in a prominent location within the visualization, such as in a corner or along the side of a chart or graph, to ensure they are easily visible and accessible.

In summary, legends are essential for effectively communicating complex information in data visualization. They provide context and clarity, help maintain consistency and accuracy, and ensure the reader can interpret the data correctly. As data visualization grows in importance across various industries, using clear and effective legends will become increasingly important for successfully communicating complex information.

Legend Tag in HTML

The <legend> tag in HTML defines a caption or title for an <fieldset> element. A <fieldset> is a grouping element used to group related form elements, such as text fields, radio buttons, checkboxes, etc. The <legend> tag provides a title or caption for the <fieldset> element, which helps to make the form more accessible and easier to understand for users.

To use the <legend> tag, first define an <fieldset> element in your HTML code. The <fieldset> element is used to group co-related form elements together and often to group form elements into sections or categories. Once you have defined your <fieldset> element, you can use the <legend> tag to provide a title or caption for the group of form elements.

Here is an illustration of how to use the <legend> tag in HTML:

    <legend>Personal Information</legend>
    <label for="name">Name:</label>
    <input type="text" id="name" name="name"><br>
    <label for="email">Email:</label>
    <input type="email" id="email" name="email"><br>
    <label for="phone">Phone:</label>
    <input type="tel" id="phone" name="phone"><br>

In this example, the <fieldset> element groups together three form elements: a text input for the user's name, an email input for the user's email address, and a telephone input for the user's phone number. The <legend> tag provides a title or caption for the <fieldset> element, which in this case is "Personal Information".

The <legend> tag is an important element for improving the accessibility of forms on the web. It helps to provide a clear and concise title or caption for the group of form elements, which can be especially helpful for users with visual impairments or those using assistive technologies like screen readers.

In addition to providing a title or caption for the <fieldset> element, the <legend> tag can be styled using CSS to customize its appearance. This allows web developers to create more visually appealing forms consistent with the look and feel of their website or application.

In conclusion, the <legend> tag is an important HTML element for creating accessible and well-structured forms on the web. By providing a clear and concise title or caption for a group of related form elements, the <legend> tag helps to make forms easier to understand and use for all users.


In conclusion, legends are vital in communicating complex information to readers on a map, chart, or any other document. They provide essential context, help to maintain consistency and accuracy and ensure that the reader can interpret the data correctly. Clear and effective legends have become increasingly important as data visualization grows across various industries. As such, designers and communicators must consider the importance of legends in their work and use them appropriately to enhance the readability and effectiveness of their visualizations. By using legends in their work, designers can make their visualizations more accessible, understandable, and impactful, leading to more informed decision-making and better communication.