What is the format of img?

img is a file compression format, mainly used to create floppy disk image files. It can be used to compress the contents of the entire floppy disk or the entire CD; files using the extension ".IMG" use this Created in a file format; the img file includes 3 basic nodes, namely "Ehfa_HeaderTag", "Ehfa_File" and "Ehfa_Entry".

The operating environment of this tutorial: Windows 10 system, Dell G3 computer.

What is the format of img?

File compression format.

The img format is a file compression format (archive format), mainly used to create a floppy disk image file (disk image). It can be used to compress the entire floppy disk (usually refers to a floppy disk, Floppy Disk or Diskette) Or the contents of the entire disc, files using the ".IMG" extension are created using this file format. The .IMG file format can be regarded as a superset of the .ISO format.

The Img file format is composed of a series of interconnected nodes. Each node has its own header file, and the nodes are connected together through their respective header files. The header file of each node records the storage location of the next node, previous node, first child node and parent node. All nodes can be easily read based on this information, and the header file of each node It also stores information such as the storage location, data size, and node structure type of each node data. Each node can be easily read according to the node's structure type. The structure type of each node is different, and the list of these structure types is stored at the end of the file.

img files include 3 basic nodes: Ehfa_HeaderTag; Ehfa_File; Ehfa_Entry. Eimg_Layer is a basic node in the Img file. This node stores the basic information of a layer (for multi-band images, usually a single band), and stores the image grayscale and geographical information of the layer in its child nodes. , projection information, statistical information, etc. Edms_State node is a child node of EImg_Layer, used to describe the basic information of a layer and image block. Edsc_Table is a child node of EImg_Layer, and its child nodes can store the layer's palette. Ehfa_Layer is a child node of EImg_Layer, marking the type of layer. The dictionaryPtr location in Ehfa_File stores the Dictionary (data dictionary). Dictionary is not a node. It defines the data structure of various nodes. Before reading the data of a node, first read the dictionary to obtain the data structure of each node.

IMG data has the following characteristics:

• A variety of image information is stored together. Remote sensing data includes image data, positioning data, sensor information and other information. Generally, the file header and image data are stored separately, while the Img file stores all types of data in one file. middle.

• Data is stored in nodes. The position of various data in the file is not fixed, but is organized through the interrelationship of nodes.

• Image data is stored in blocks. Blocked storage reduces the consumption of image reading system resources, thereby greatly accelerating the speed of image display; at the same time, it avoids the impact of large data volume on the efficiency of image processing algorithms.

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