Patent Application
20100182316
Topographical models of geographical areas may be used for many applications. For example, topographical models may be used in flight simulators and other planning missions. Furthermore, topographical models of man-made structures, for example, cities, may be extremely helpful in applications, such as, cellular antenna placement, urban planning, disaster preparedness and analysis, and mapping.
Various types of topographical models are presently being used. One common topographical model is a digital elevation model (DEM). The DEM is a sampled matrix representation of a geographical area, which may be generated in an automated fashion by a computer. In the DEM, coordinate points are made to correspond with a height value. DEMs are typically used for modeling terrain where the transitions between different elevations, for example, valleys, mountains, are generally smooth from one to a next. That is, a basic DEM typically models terrain as a plurality of curved surfaces and any discontinuities therebetween are thus “smoothed” over. Another common topographical model is a digital surface model (DSM). The DSM is similar the DEM but may be considered as further including details regarding buildings, vegetation, and roads, in addition to information relating to terrain.
U.S. Pat. No. 6,654,690 to Rahmes et al., which is assigned to the assignee of the present application, and is hereby incorporated herein in its entirety by reference, discloses an automated method for making a topographical model of an area including terrain and buildings thereon based upon randomly spaced data of elevation versus position. The method includes processing the randomly spaced data to generate gridded data of elevation versus position conforming to a predetermined position grid, processing the gridded data to distinguish building data from terrain data, and performing polygon extraction for the building data to make the topographical model of the area including terrain and buildings thereon.
In certain planning applications, for example, wireless communication system deployment, data describing the ground occupancy above the terrain is used, i.e. clutter data. In these applications, the clutter data is typically used for radio frequency propagation analysis. The clutter data is typically organized in a plurality of classes, for example, dense trees, sparse trees, agriculture, industrial, urban, and dense urban. Each of the classes of clutter data has corresponding propagation information, such as, height, diffraction factor, and absorption.
Typical clutter data includes two-dimensional (2D) heights, which may result in non-optimal analysis. There are some disclosed methods for inserting three-dimensional (3D) height data into 2D clutter data. For example, the 3D height data may be collected in the field, or the clutter objects in large models may be manually attributed with 3D data. These approaches may be time consuming and tedious. More specifically, this type of 3D rendering for 2D clutter objects may be lengthy and expensive since the modeler renders the object in 3D, locates the clutter areas, and determines where the rendered object correlates in the 2D space.
For example, U.S. Pat. No. 7,298,316 to Tsai et al. discloses a device for detecting clutter blocks and an interference source for dynamically establishing a 2D clutter map. The device may include a clutter block detecting module for accumulating a plurality of range cell data of each detecting area and for comparing the accumulated value with a clutter block level to define the position of a clutter block. The device may also include an interference source detecting module for accumulating all range cell data in each radar beam area and for comparing the accumulated value with an interference source reference level to detect whether any interference source exists. The device also includes a clutter map establishing module for saving the clutter maps on different beam areas in three memory blocks.
In view of the foregoing background, it is therefore an object of the present invention to provide a geospatial modeling system for providing accurate three-dimensional (3D) clutter information.
This and other objects, features, and advantages in accordance with the present invention are provided by a geospatial modeling system comprising a geospatial model database having stored therein an initial 3D digital surface model (DSM) of a geographical area, and a plurality of two-dimensional (2D) clutter data files for respective different types of possible non-building clutter. The geospatial modeling system may also include a processor cooperating with the geospatial model database to generate an updated DSM including therein 3D clutter data based upon the initial DSM and the 2D clutter data files. Advantageously, the geospatial modeling system readily provides 3D clutter data with the DSM.
In some embodiments, the processor may further cooperate with the geospatial model database to generate the updated DSM including therein 3D clutter data by at least generating a bare earth digital terrain model (DTM) from the initial DSM, and combining the 2D clutter data files with the bare earth DTM. Moreover, the processor may further generate height histogram data and combine the 2D clutter data files with the bare earth DTM using the height histogram data.
More specifically, the geospatial model database may store the 2D clutter data files comprising 2D clutter data files associated with at least one of trees, agriculture, industrial development, and urban development. Also, the geospatial model database may store the 2D clutter data files with each of the 2D clutter data files comprising a number of vertices. The 3D clutter data may have a desired detail value based upon the number of vertices. The processor may further cooperate with the geospatial model database to generate the updated DSM including therein 3D clutter data having at least one of a minimum height value, a maximum height value, a mean height value, a standard deviation value, a base height value, an area value, a slope valuer a width value, and a length value.
In some embodiments, the geospatial modeling system may further comprise a display coupled to the geospatial model database and the processor to display the updated DSM. The processor may further cooperate with the geospatial model database to generate the initial DSM using image correlation on aerial earth images.
Another aspect is directed to a computer implemented method for modeling an initial 3D DSM of a geographical area and a plurality of 2D clutter data files for respective different types of possible non-building clutter. The computer implemented method may include generating an updated DSM including therein 3D clutter data based upon the initial DSM and the 2D clutter data files.
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.
Referring initially to
The geospatial model database 21 illustratively stores at Block 33 an initial three-dimensional (3D) digital surface model (DSM) of a geographical area, and a plurality of two-dimensional (2D) clutter data files for respective different types of possible non-building clutter As will be appreciated by those skilled in the art, the 2D clutter data files comprise at least land use clutter data and land cover clutter data.
For example, the 2D clutter data files may comprise shapefiles. In certain embodiments, the geospatial modeling database 21 may generate the initial DSM using image correlation on aerial earth images, for example. In yet other embodiments, the processor 22 may generate the initial DSM using the method disclosed in U.S. Patent Application Publication No. 2007/0265781 to Nemethy et al., also assigned to the assignee of the present invention, and the entire contents of which are incorporated by reference herein.
At Block 35, the processor 22 further illustratively cooperates with the geospatial model database 21 for generating a bare earth digital terrain model (DTM) from the initial DSM, and combining at Block 37 the 2D clutter data files with the bare earth DTM. Once the processor 22 has combined the 2D clutter files with the bare earth DTM, the processor illustratively cooperates with the geospatial model database 21 for generating an updated DSM including therein 3D clutter data based upon the initial DSM and the 2D clutter data files. (Block 39). Advantageously, the geospatial modeling system 20 automatically provides quick and accessible 3D clutter data without the cumbersomeness and cost of typical methods.
The geospatial modeling system 20 may provide the updated DSM with 3D clutter data on the display 23 for advantageous viewing by the user. In certain embodiments, the processor 22 may further generate height histogram data and combine the 2D clutter data files with the bare earth OTM using the height histogram data. More specifically, statistical histogram analysis is used to determine the best clutter object height based on all the height post values within the boundary of the given object, as will be appreciated by those skilled in the art. The method ends at Block 41.
Optionally and as will be appreciated by those skilled in the art, the geospatial model database 21 may store the 2D clutter data files comprising 2D clutter data files associated with at least one of trees, agriculture, industrial development, urban development, dense urban, light urban, urban residential, suburban residential, paved areas, native forest dense, native forest medium, exotic forest dense, exotic forest medium, scrub, open areas, wetland, ice and snow, and water.
Also, in embodiments where the 2D clutter data files comprise shapefiles, the geospatial model database 21 may store the shape files with each having a number of vertices, i.e. the 2D clutter data files may have a certain level of detail. Based upon the this level of detail in the shapefiles, the geospatial modeling system 20 sets the desired level of detail for the 3D clutter data.
For example, the processor 22 may further cooperate with the geospatial model database 21 for generating the updated DSM including therein 3D clutter data having at least one of a minimum height value, a maximum height value, a mean height value, a standard deviation value, a base height value, an area value, a slope value, a width value, and a length value.
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Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims.
The present invention relates to the field of geospatial modeling, and, more particularly, to geospatial modeling of digital surface models and related methods.
