USA As Represented by Secretary of the Navy

John T Sample

Elias Z K Ioup

Bruce Y Lin

Christopher J Michael

Norman Schoenhardt

Frank P McCreedy

Elias Ioup

Lev I Shulman

Brent Barré

Hillary C Mesick

Systems and methods are provided for reducing error in data compression and decompression when data is transmitted over low bandwidth communication links, such as satellite links. Embodiments of the present disclosure provide systems and methods for variable block size compression for gridded data, efficiently storing null values in gridded data, and eliminating growth of error in compressed time series data.

Reducing error in data compression

Embodiments relate to visualization of positional geospatial uncertainty. Initially, a map image request for geographic features is received from a client computing device, where the map image request includes an uncertainty type, a distribution shape, and a selected visualization technique. An uncertainty buffer pixel size is determined based on a geographic distance covered by the distribution shape. At this stage, an uncertainty buffer of the uncertainty buffer pixel size is iterated across, and uncertainty is rendered at each position along the uncertainty buffer by determining a corresponding distribution probability from a probability distribution function at a current pixel position, mapping the corresponding distribution probability to a corresponding visual value of the selected visualization technique, rendering an uncertainty feature for the corresponding distribution probability around the geographic feature at the current pixel position and according to the corresponding visual value; and advancing the current pixel position based on the uncertainty type.

Visualization of positional geospatial uncertainty

Embodiments relate to converting imagery to a polar projection. Initially, a map request that specifies the polar projection for a geographic area is obtained. The geographic area into a number of image regions. A first source image is obtained for a first image region, where the first source image is at a first target resolution, and a second source image is obtained for a second image region, where the second source image is at a second target resolution that is determined based on a geographic location of the second image region. The first source image and the second source image are projected into the polar projection to obtain a single output image. At this stage, a polar coordinate system that corresponds to the polar projection is used to render the single output image in a spatial map.

Converting imagery and charts to polar projection

Embodiments relate to converting spatial features to a map projection. Initially, a map request that specifies the map projection for a geographic area is obtained. A spatial feature is identified for projecting into the map projection. Until a bisect threshold is satisfied for each line segment in the spatial feature, a bisect is determined for each of the line segments; each line segment is projected into the map projection; and if the bisect threshold is not satisfied for a line segment, the line segment is divided into subsegments, where the bisect threshold specifies an error distance for the line segment after projection. The modified spatial feature is projected into the map projection to obtain a projected spatial feature, and a polar coordinate system that corresponds to the map projection is used to render the projected spatial feature in a spatial map.

Converting spatial features to map projection

Embodiments relate to hash-based synchronization of geospatial vector features. Initially, a list of spatial data layers in a source spatial datastore is obtained. For each of the spatial data layers, a source layer hash is determined for a source data layer of the spatial data layers, a destination data layer is identified in a destination spatial datastore that is related to the source data layer, where the destination data layer is associated with a destination layer hash, and in response to determining that the source layer hash and the destination layer hash do not match, source features from the source data layer are selectively synchronized to the destination data layer.

Hash-based synchronization of geospatial vector features

System and method for storing a dataset of image tiles. Method includes determining a number of zoom levels, accessing a cluster file that includes a subset of the zoom levels, and accessing the image tiles. For each of the image tiles, a cluster name is computed. For each of the image tiles, if the cluster file has a name that matches the computed cluster name, an image tile pointer is stored in a fixed length index, and the image tile associated with the computed cluster name is stored. For each of the image tiles, if the cluster file name does not match the computed cluster name, another subset of the zoom levels is computed, a new cluster file is created, an image tile pointer is created and stored, and the image tile is stored associated with the computed cluster name in the new cluster file according to the image tile pointer.

System and method for storing a dataset of image tiles

A system and method for hierarchical synchronization of tiles between a first dataset and a second dataset by computing and storing multiple composite cluster hash values for multiple clusters in the first and second dataset. For each of the composite cluster hash values, comparing a composite cluster hash value of a particular cluster in the first dataset with a composite cluster hash value of a corresponding cluster in the second dataset. When the composite cluster hash values of the corresponding clusters do not match, retrieving all tile hashes corresponding to all the tiles from the non-matching cluster in the first dataset, and retrieving all tile hashes corresponding to all the tiles from the non-matching cluster in the second dataset. Finally, determining the one or more changed tiles between the non-matching cluster in the first dataset and the non-matching cluster in the second dataset by comparing the corresponding tile hashes.

System and method for hierarchical synchronization of a dataset of image tiles

System and method for displaying an encoded standard-formatted image with information including, but not limited to, geospatial information. This information, possibly in mark-up language format, can be quickly accessed and used to modify the image to which it is appended, or it can be ignored because the image itself remains unchanged.

System and method for encoding standard-formatted images with information

System and method for providing a probabilistic order of tiles relative to a current section of a video that a user is viewing. A cache implementation uses this ordering to decide what tiles to evict from the cache, i.e. which tiles will probably not be accessed within a particular timeframe, but not when to evict (this is up to the cache implementation). A cache implementation can also use the prioritized list of the present embodiment to pre-fetch tiles.

System and method for interactive spatio-temporal streaming data

System and method for encoding standard-formatted images with information including, but not limited to, geospatial information. This information, possibly in mark-up language format, can be quickly accessed and this enables the standard-formatted images to be shown in geospatial information systems as map images, while preserving their compatibility with other systems like web browsers and mobile phones.

Growing community of inventors

Pearl River, LA, United States of America

John T Sample