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GRAPHICAL DATA EXCHANGE FORMATS .jpg .gif .tif.

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Presentation on theme: "GRAPHICAL DATA EXCHANGE FORMATS .jpg .gif .tif."— Presentation transcript:

1 GRAPHICAL DATA EXCHANGE FORMATS .jpg .gif .tif

2 Graphics Interchange Format (.GIF)
Byte Image Data Stored in Row Major Order

3 Contains RGB Values for
Graphics Interchange Format (.GIF) 768 Byte Indexed Color Table Contains RGB Values for 256 Colors or Gray Tones

4 Graphics Interchange Format (.GIF)
Lempel, Ziv, Welch (LZW) image Compression Used on all Images Looks for and Codes Repeated Pixel Patterns in the Image Works Best for Large Areas of the Same Color

5 Pixel Density is Important
Choosing the Correct Pixel Density is Important for Maintaining Image Quality

6 Joint Photographic Experts Group (.JPG)
File Format One or Three-Byte Image Data Stored in Row Major Order

7 Joint Photographic Experts Group (.JPG) Data are Compressed using a
File Format Data are Compressed using a “Lossy" Method where Some Data are Lost

8 Joint Photographic Experts Group (.JPG)
File Format Data are Compressed using a "Lossy" Method where some Data are Lost User Specifies the Level of Image Quality from Best (10) to Worst (1)

9 Joint Photographic Experts Group (.JPG)
File Format Image Quality Generally Good at Higher Levels of Compression Better Compression Scheme for Photomaps and Relief Shading than .GIF

10 Tagged Image File Format (.tif or .tiff)

11 TIFF Advantages Flexible and adaptable file format.
Can have multiple images and data in a single file through the inclusion of "tags" in the file header. Tags indicate the basic geometry of the image, such as its size, or if one of several image compression options are used.

12 TIFF World File --GEOTIFF (.tfw)

13 ESRI TIFF World File – 6 ASCII Lines
Horizontal distance in meters represented by each pixel. Rotation angle about the y axis. Rotation angle about the x axis. Vertical distance in meters represented by each pixel. Normally negative because an image has its origin in the top left corner. Easting coord. of the center of the top left pixel. Northing coord. of the center of the top left pixel.

14 TFW File Example 0.6 -0.6 Sometimes will have two additional lines: Grid zone or coordinate system Datum


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