(registered 2019-08-21, last updated 2019-08-21) Type name: application Subtype name: sipc Required parameters: N/A Optional parameters: N/A Encoding considerations: Binary: This media type requires encoding on transports not capable of handling binary Security considerations: SIPC utilizes a structure that can store arrays of point cloud data and metadata corresponding to this point cloud data. The fields defined in the SIPC are of a descriptive nature and provide information that may be useful to facilitate viewing, rendering, and cataloging of data by a recipient. As such, the fields currently defined in the SIPC format do not in and of themselves create additional security risks, since the fields are not used to induce any behavior by the recipient application. However, SIPC has an extensible structure, supporting both extensions defined and standardized by NGA and vendor-defined extensions, thus presenting additional security risks. It is thus possible that data embedded in a SIPC file could be used to induce actions on the part of the recipient, either through a well-defined and known software capability, or as a result of malware or other malicious exploitation. In addition, SIPC uses HDF5 as its underlying data format. Any security concerns related to HDF5 also apply to SIPC. SIPC includes metadata fields specifying confidentiality markings, access rights and handling of the data, including requirements if the file is to be maintained in a secure environment. In this case the intention is that alteration or removal of this metadata from the file would be treated as an offense under national or international law, as would be removing the file from a secure environment. While SIPC does not include the ability within itself to encrypt the contents, end-to-end encryption (e.g., HTTPS, TLS, SSL) should be used when transmitting files that include sensitive data or where access is restricted. Once received, these sensitive files should also be encrypted at rest using storage-based encryption mechanisms. SIPC, given its use of HDF5, does provide for the data to be compressed, and thus processing of the data could consume significantly more resources than might be assumed solely based on the compressed size of the data file. Interoperability considerations: SIPC data is encoded using HDF5 as the underlying data format. Any tool that consumes an HDF5 file can provide access to the SIPC data, even if it does not understand the semantics of the data or the specific organization of the data within the file. Referenced to published specification: NGA.STND.0054-1 SIPC-DIDD - Sensor Independent Point Cloud (SIPC) Volume 1 Design and Implementation Description Document (DIDD) NGA.STND.0054-2 SIPC-FFDD - Sensor Independent Point Cloud (SIPC), Volume 2, File Format Description Document (FFDD) This standard is available at the National System for Geospatial Intelligence (NSG) Standards Registry at the following URLs: https://nsgreg.nga.mil/JESC-approved.jsp https://nsgreg.nga.mil/doc/view?i=4206 https://nsgreg.nga.mil/doc/view?i=4207 Application usage: SIPC defines a general-purpose LiDAR (Light Detection and Ranging) point cloud format and provides a useful root dataset for multiple downstream-derived products with added utility and intelligence value. SIPC-compliant point cloud data allows representation from various sensors and processing systems without detailed engineering and design knowledge of particular sensors or processing systems from which the dataset are produced. At the most fundamental level, SIPC is a standard for storing point cloud data in a 3D Cartesian (x, y, z) space, each with an arbitrary number of associated parameters such as intensity, wavelength, polarization, time of collect, or platform identification. In that regard, SIPC provides a rich standard set of metadata that describes the point data itself. Fragment identifier considerations: N/A Restrictions on usage: The SIPC standard is intended to be a US Government standard open to the public. There are no ITAR (International Traffic in Arms Regulations) specific data within the MIPC specification. There are no patents associated with the specification. Copyrights belong to the US Government to the extent they do for any other standard specification published in this manner. There is no cost for accessing this standard, and there is no use license. Additional information: Magic number: To first verify that the file is HDF5 formatted, the data consumer must search for the HDF5 superblock. The superblock may begin at certain predefined offsets within the HDF5 file, allowing a block of unspecified content for users to place additional information at the beginning (and end) of the HDF5 file without limiting the HDF5 Library’s ability to manage the objects within the file itself. This feature was designed to accommodate wrapping an HDF5 file in another file format or adding descriptive information to an HDF5 file without requiring the modification of the actual file’s information. The superblock is located by searching for the HDF5 format signature at byte offset 0, byte offset 512, and at successive locations in the file, each a multiple of two of the previous location; in other words, at these byte offsets: 0, 512, 1024, 2048, and so on. The first eight bytes of the superblock are “\211HDF\r\n\032\n” (0x89, 0x48, 0x44, 0x46, 0x0d, 0x0a, 0x1a, 0x0a) Once the file is identified as an HDF5, there is unfortunately no specific internal data element that can authoritatively identify the file as an SIPC file; the data consumer must attempt to parse the contained data according to the SIPC data model, and if successful, can assume that the HDF file conforms to the SIPC data model. File extension: .h5 Intended usage: LIMITED USE For the transmission and indication of Point Cloud Data (from LiDAR sources) in the SIPC format. Contact name: Bryan Blank Contact email: ntbchair&nga.mil Author/change controller: National Imagery Transmission Format Technical Board Geospatial-Intelligence Standards Working Group NGA National Center for Geospatial Intelligence Standards (NCGIS) Mail Stop N32 7500 GEOINT Drive Springfield, VA 22150 USA