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CADRG (Compressed ARC Digitized Raster Graphics) is an abbreviation for "Compressed ARC Digitized Raster Graphics," primarily used for storing and transmitting raster images in geospatial data. It is commonly employed in military and surveying fields. This format optimizes data storage efficiency through compression technology and supports high-precision digital representation of geographic information, typically requiring professional software for import and processing. In GIS applications, CADRG format often needs to be converted to a file geodatabase raster to improve subsequent analysis efficiency.

RPF (Raster Product Format, U.S. Department of Defense standard) is a standardized data structure established in 1994, serving as the U.S. military's standard for geospatial databases composed of rectangular arrays of pixel values (e.g., digitized maps or images) in compressed or uncompressed forms. Its intended purpose is to manage the design of a series of digital data exchange products, including digital maps, imagery, and other geospatial data for military applications. Designed to be a versatile and adaptable format for raster products, whether compressed or uncompressed, RPF aims to enable applications to directly use data stored in computer-readable RPF formats on exchange media (e.g., CD-ROMs) without requiring further conversion or manipulation. The format is characterized by a hierarchical directory structure, including a catalog file (sometimes referred to as an A.TOC file) and one or more frame directories representing raster data frames.

ADF (ArcInfo Binary Grid Format) is a proprietary raster data format developed by Esri. It is used for storing and managing raster data, which can contain various types of geospatial information such as elevation data, land cover types, vegetation indices, etc. The ADF format can store raster layers with different resolutions and data types, making it significant in GIS applications.

Boggs Eumorphic Projection is a pseudocylindrical equal-area map projection used for world maps, often featuring multiple interruptions. Its equal-area characteristic makes it suitable for displaying the spatial distribution of phenomena. Proposed by Samuel Whittemore Boggs (1889–1954) in 1929, this projection aimed to provide an alternative to the Mercator projection for representing global regional relationships. Boggs served as the Geographer of the U.S. Department of State from 1924 until his death. The Boggs Eumorphic Projection is occasionally used in textbooks and atlases.

Hammer–Aitoff variant is an improved version of the Lambert azimuthal equal-area projection. The Hammer projection is an equal-area projection with an elliptical graticule. It is also referred to as the Hammer–Aitoff projection. This projection is suitable for small-scale mapping.

Aitoff projection is a specialized map projection method first proposed by the German mathematician David A. Aitoff in 1889. As a compromise projection, it aims to balance distortions in angle, area, and distance, making it suitable for global overview maps. The Aitoff projection is an improvement upon the azimuthal equidistant projection. By horizontally stretching the original hemispherical projection to twice its width, it forms an elliptical map where the width is double the height. This projection is particularly well-suited for displaying regions centered on specific points, such as polar areas or cities, while providing a relatively balanced view of the world.

New Zealand Map Grid Projection is a conformal map projection technology specifically designed for large-scale mapping of New Zealand. It employs the complex Cauchy-Riemann equations for projection calculations, with its central point set at 173° East longitude and 41° South latitude. It is important to note that this projection method is only suitable for large-scale mapping within New Zealand and may not be applicable for mapping other regions.

Gnomonic Projection is a perspective azimuthal projection that uses the center of the sphere as the light source. It projects great circles on the spherical surface (such as meridians and the equator) as straight lines, making it commonly used in navigation, astronomy, and seismic analysis. Its key characteristic is the absence of distortion at the projection center, but extreme distortion occurs at the edges. While suitable for mapping great-circle routes or analyzing linear paths, it does not preserve area or angular relationships.

A Compound CRS achieves unified representation of multi-dimensional spatial data by combining multiple coordinate reference systems (CRS). For example, it integrates a planar coordinate system (e.g., EPSG:7661) with an elevation system (e.g., EPSG:3855) to form a complete "planar + elevation" spatial description. Its core features include ensuring consistency between horizontal and vertical coordinate systems through associated parameters (such as ellipsoids and datums), making it suitable for fields requiring simultaneous expression of planar positions and elevations, such as terrain modeling and 3D GIS analysis. Technically, a Compound CRS typically comprises a horizontal CRS and a vertical CRS, unified through nested or associated parameters.

Albers equal-area conic projection is an equal-area conic projection that utilizes two standard parallels. Compared to projections with only one standard parallel, this approach helps reduce distortion to some extent. It is best suited for mapping large continental areas extending predominantly in an east-west direction in the mid-latitudes and is commonly used for maps of the contiguous United States, Europe, and Australia.