Abstract: Systems and methods for storing and retrieving geospatial data in a geographic information system are provided. Geospatial data can be spatially partitioned along axes of a spherical coordinate system associated with a virtual globe or other spheroid into a plurality of discrete geospatial volumes pursuant to a hierarchical spatial partitioning scheme. For instance, geospatial data can be spatially partitioned into geospatial volumes along surfaces of constant latitude, longitude, and altitude defined by the spherical coordinate system. The discrete geospatial volumes can be stored as nodes in a hierarchical tree data structure. Additional methods are provided for portioning geospatial objects, such as tiles or discrete geospatial volumes, in tritree to reduce polar distortions.

Abstract: Systems and methods for storing and retrieving geospatial data in a geographic information system are provided. Geospatial data can be spatially partitioned along axes of a spherical coordinate system associated with a virtual globe or other spheroid into a plurality of discrete geospatial volumes pursuant to a hierarchical spatial partitioning scheme. For instance, geospatial data can be spatially partitioned into geospatial volumes along surfaces of constant latitude, longitude, and altitude defined by the spherical coordinate system. The discrete geospatial volumes can be stored as nodes in a hierarchical tree data structure. Additional methods are provided for portioning geospatial objects, such as tiles or discrete geospatial volumes, in tritree to reduce polar distortions.

Abstract: Systems and methods for storing and retrieving geospatial data in a geographic information system are provided. Geospatial data can be spatially partitioned along axes of a spherical coordinate system associated with a virtual globe or other spheroid into a plurality of discrete geospatial volumes pursuant to a hierarchical spatial partitioning scheme. For instance, geospatial data can be spatially partitioned into geospatial volumes along surfaces of constant latitude, longitude, and altitude defined by the spherical coordinate system. The discrete geospatial volumes can be stored as nodes in a hierarchical tree data structure. Additional methods are provided for portioning geospatial objects, such as tiles or discrete geospatial volumes, in tritree to reduce polar distortions.

Abstract: Systems and methods for providing smooth level of detail (“LOD”) transition for textures in a graphics applications are disclosed. The texture LOD of a first frame of imagery can be compared to a second texture LOD for a current frame. For areas where the second LOD is higher than the first LOD, an LOD fade from the first LOD to the second LOD can be performed to provide a smooth LOD transition. The LOD fade can be implemented by generating a blend between textures at the first LOD and the second LOD. In one aspect, the blend is generated based on an interpolant value calculated based on the difference between the first LOD and the second LOD. The interpolant value can be incremented in subsequent frames to achieve a desired fade rate for the transition. The fade rate can be variable such that the LOD transition time remains constant.

Abstract: Systems and methods for providing smooth level of detail transitions for geometric objects, such as geometric terrain tiles, are provided. In one embodiment, a parent geometric tile associated with a first level of detail can be partitioned into sub-tiles. The sub-tiles can be blended independently with child geometric tiles associated with a second level of detail. The blends can be adjusted as a function of camera distance over a transition range to provide a smooth level of detail transition. Various enhancements and modifications can be made to the level of detail transition, such as implementing a bias in the level of detail calculation, implementing an unpop algorithm over only a subset of the transition range, implementing a time based fade during a camera stop, and other enhancements.

Abstract: Systems and methods for storing and retrieving geospatial data in a geographic information system are provided. Geospatial data can be spatially partitioned along axes of a spherical coordinate system associated with a virtual globe or other spheroid into a plurality of discrete geospatial volumes pursuant to a hierarchical spatial partitioning scheme. For instance, geospatial data can be spatially partitioned into geospatial volumes along surfaces of constant latitude, longitude, and altitude defined by the spherical coordinate system. The discrete geospatial volumes can be stored as nodes in a hierarchical tree data structure. Additional methods are provided for portioning geospatial objects, such as tiles or discrete geospatial volumes, in tritree to reduce polar distortions.

Abstract: Systems and methods for providing smooth level of detail (“LOD”) transition for textures in a graphics applications are disclosed. The texture LOD of a first frame of imagery can be compared to a second texture LOD for a current frame. For areas where the second LOD is higher than the first LOD, an LOD fade from the first LOD to the second LOD can be performed to provide a smooth LOD transition. The LOD fade can be implemented by generating a blend between textures at the first LOD and the second LOD. In one aspect, the blend is generated based on an interpolant value calculated based on the difference between the first LOD and the second LOD. The interpolant value can be incremented in subsequent frames to achieve a desired fade rate for the transition. The fade rate can be variable such that the LOD transition time remains constant.

Abstract: Systems and methods for storing and retrieving geospatial data in a geographic information system are provided. Geospatial data can be spatially partitioned along axes of a spherical coordinate system associated with a virtual globe or other spheroid into a plurality of discrete geospatial volumes pursuant to a hierarchical spatial partitioning scheme. For instance, geospatial data can be spatially partitioned into geospatial volumes along surfaces of constant latitude, longitude, and altitude defined by the spherical coordinate system. The discrete geospatial volumes can be stored as nodes in a hierarchical tree data structure. Additional methods are provided for portioning geospatial objects, such as tiles or discrete geospatial volumes, in tritree to reduce polar distortions.

Abstract: Systems and methods for providing smooth level of detail transitions for geometric objects, such as geometric terrain tiles, are provided. In one embodiment, a parent geometric tile associated with a first level of detail can be partitioned into sub-tiles. The sub-tiles can be blended independently with child geometric tiles associated with a second level of detail. The blends can be adjusted as a function of camera distance over a transition range to provide a smooth level of detail transition. Various enhancements and modifications can be made to the level of detail transition, such as implementing a bias in the level of detail calculation, implementing an unpop algorithm over only a subset of the transition range, implementing a time based fade during a camera stop, and other enhancements.

Abstract: Systems and methods for storing and retrieving geospatial data in a geographic information system are provided. Geospatial data can be spatially partitioned along axes of a spherical coordinate system associated with a virtual globe or other spheroid into a plurality of discrete geospatial volumes pursuant to a hierarchical spatial partitioning scheme. For instance, geospatial data can be spatially partitioned into geospatial volumes along surfaces of constant latitude, longitude, and altitude defined by the spherical coordinate system. The discrete geospatial volumes can be stored as nodes in a hierarchical tree data structure. Additional methods are provided for portioning geospatial objects, such as tiles or discrete geospatial volumes, in tritree to reduce polar distortions.

Abstract: Systems and methods for providing smooth level of detail (“LOD”) transition for textures in a graphics applications are disclosed. The texture LOD of a first frame of imagery can be compared to a second texture LOD for a current frame. For areas where the second LOD is higher than the first LOD, an LOD fade from the first LOD to the second LOD can be performed to provide a smooth LOD transition. The LOD fade can be implemented by generating a blend between textures at the first LOD and the second LOD. In one aspect, the blend is generated based on an interpolant value calculated based on the difference between the first LOD and the second LOD. The interpolant value can be incremented in subsequent frames to achieve a desired fade rate for the transition. The fade rate can be variable such that the LOD transition time remains constant.

Abstract: A portable sand blasting device comprising a housing adapted to be held and manipulated manually and to support an electric motor having a rotatable output shaft. An impeller is mounted on the motor output shaft and has an inlet opening communicating with an inlet chamber which receives air and entrained sand through a conduit extending to a sand pouch adapted to be carried on the body of the operator. The impeller also has a plurality of radial passageways each of a generally circular configuration but with a somewhat "V"-shaped trailing wall. A spiral discharge chamber receives the air and entrained sand from outer end of the impeller passageways and conducts the same to a discharge opening and an associated nozzle. The spiral discharge chamber has a "V"-shaped outer wall with the open end of the "V" facing the impeller.