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JTLS New Terrain Generation Capability

JTLS New Terrain Generation Capability. Harold Yamauchi ROLANDS & ASSOCIATES 16 th JTLS International Users Conference 4 March 2014. Background. Current JTLS terrain representation: Hexagon grid projected upon a 2000 NM by 2000 NM area (terrain board)

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JTLS New Terrain Generation Capability

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  1. JTLS New Terrain Generation Capability Harold Yamauchi ROLANDS & ASSOCIATES 16th JTLS International Users Conference 4 March 2014

  2. Background • Current JTLS terrain representation: • Hexagon grid projected upon a 2000 NM by 2000 NM area (terrain board) • Hexagons are typically in the 5 KM – 7.5 KM range (from hex edge to opposite hex edge) • Terrain is not represented beyond the terrain board • JTLS Model allows placement of naval units, airbases and squadrons off the terrain board without terrain-related restrictions • New terrain requirements (J-7): • Represent terrain world-wide • Any type of unit should be able to be placed anywhere in the world and operate in the same manner as they currently operate on the JTLS terrain board • Implication: Abandon terrain board concept ROLANDS & ASSOCIATES Corporation

  3. Implementation • Review three areas of effort: • Define terrain characteristics and features necessary for a JTLS game • Search for data provider(s) who can provide the terrain data • Development of a graphical tool for the JTLS user to access the data, and edit and save portions of it for a specific JTLS scenario ROLANDS & ASSOCIATES Corporation

  4. Terrain Data Types • Seven terrain types: • Air Corridor Network - Paths flown by aircraft while monitored by air traffic control • Rail Network - Connected network of railroad lines (mainlines only) • River Network - Connected network of (navigable)rivers used by small boats and barges • Road Network - Roads that a ground unit or a convoy should follow • Shoreline Segments - Represents shoreline locations or divisions between a land mass and surrounding water • National Boundary Segments - Represents the borders between two political entities • Terrain Grid - A grid representing the underlying terrain • JTLS already represents the first six in some form (not necessarily as networks) • Terrain grids are a new element for representing terrain ROLANDS & ASSOCIATES Corporation

  5. General Network Representation • A terrain feature represented by a network (air corridor, rail, river or road network) is used by the JTLS model to: • Find an (optimal) path between any two points that can be visited within the network • Schedule movement for an object following that path • All networks are comprised of arcs and nodes • A node contains location information in latitude and longitude, and possibly some additional information such as a name to be viewed by the JTLS user or a delay time (for a rail, river or road node) for scheduling movement through the network. • An arc connects two nodes • Each arc contains information that the JTLS model uses to find a path through the network, or uses to affect movement of an object traversing the arc. An example is the representative distance of a rail, river or road arc. • An arc is considered bi-directional ROLANDS & ASSOCIATES Corporation

  6. Terrain Grid ( 1 of 4) • Terrain is represented in levels of detail (LOD). Higher LODs are nested inside lower LODs. • For each LOD, terrain is represented by grid squares of fixed size. As the LOD increases, the size of the grid decreases. • Grid squares are equal in size from a latitude and longitude perspective, not a distance perspective. (The JTLS model will properly process the differences of area covered by each grid square.) • Largest grid size (lowest LOD) is 10 degrees by 10 degrees. Smallest grid size (highest LOD) is 30 seconds by 30 seconds. (See Figure 1) • Terrain characteristics of the grid affect the JTLS model, such as the ability of sensors to detect objects and ground unit mobility ROLANDS & ASSOCIATES Corporation

  7. Terrain Grid ( 2 of 4) Figure 1. Terrain Grid Representation Examples of grids of size 10 degree x 10 degree, 5 degree x 5 degree, 2 degree x 2 degree, 30 minute x 30 minute and 5 minute x 5 minute. ROLANDS & ASSOCIATES Corporation

  8. Terrain Grid ( 3 of 4) • Each grid square is assigned a terrain type: • Open • Rolling Hills • Forest • Jungle • Desert • Swamp • Mountain • City • Ocean • Small Island ROLANDS & ASSOCIATES Corporation

  9. Terrain Grid ( 4 of 4) • Each grid is assigned a road coverage type as follows: • No Roads • Poor Roads • Good Roads • Other grid attributes: • Max Elevation • Average Elevation • Average Depth ROLANDS & ASSOCIATES Corporation

  10. Data Sources (1 of 2) • R&A is currently searching for sources of unclassified terrain data in ESRI shape file format. • Both commercial vendors and internet sites are being considered. • Issues: • A single source would be ideal, however no source has all the data being sought: air corridors from air charts, roads, rivers, railways, national boundaries, shorelines, terrain characteristics and elevation. • Shape files include a binary .shp file that hold the coordinates of some terrain features and a dBase III .dbf file holding the attributes of the features. There is no standard applied to the structure of the .dbf file. The attributes included in the .dbf file is left to the provider. Many needed attributes such as width, depth and height are not included. ROLANDS & ASSOCIATES Corporation

  11. Data Sources (2 of 2) • For elevation, R&A is using NOAA’s ETOP01 Bedrock Global Relief Model • Elevations are held in 1 minute by 1 minute grids that span from pole to pole and from -180 degrees to 180 degrees in longitude • In order for the development of the terrain tool to proceed, R&A is currently using VMAP0 data in shape file format obtained from the GIS Lab website. ROLANDS & ASSOCIATES Corporation

  12. JTLS Terrain Tool Design • Objectives: • Provide the JTLS user a method to retain reusable terrain data in a master database • Provide the JTLS user with a graphical tool to access this master data, edit and save portions of the data for a specific JTLS scenario • Export the data in a JTLS scenario format • These capabilities require the addition of a graphical tool (called the JTLS GIS) for preparing terrain grids, terrain characteristics, national boundaries, shorelines and all of the networks previously listed. ROLANDS & ASSOCIATES Corporation

  13. Deriving JTLS Scenario Formatted Files (1 of 2) • Summary of the process (see Figure 2): Step 1. Shape files that provide the type of data needed for JTLS are added to the master database Step 2. Reformat data to master database specifications Step 3. Data covering the desired scenario theater are selected graphically from the JTLS GIS tool for a new project. Step 4. The terrain features (represented as points, polylines and polygons) are edited as required with the JTLS GIS tool and can be saved back to the project. Step 5. The data can be exported at any time to the associated scenario files. These files are currently to be provided in ASCII text format. ROLANDS & ASSOCIATES Corporation

  14. Projects (3) Select data from Master DB for individual projects (5) Export to scenario files (2) Reformat the data and store Scenario Files *.rr *.rr_nn etc. #1 JTLS GIS External ESRI Shape File Sources Master Shape File DB Deriving JTLS Scenario Formatted Files (2 of 2) #2 (1) Obtain various shape files #3 (4) Edit project data Figure 2. Steps for Deriving JTLS Scenario Files ROLANDS & ASSOCIATES Corporation

  15. Thinning Networks • Real-world data of rail, river and road features are highly detailed polylines containing many (often hundreds but sometimes thousands of) points • When converted to arcs and nodes, and if left as is, the sheer numbers of arcs and nodes will have a major impact on JTLS memory resources and computational speed • The solution is to provide the JTLS user with the ability to tradeoff detail (numbers of arcs and nodes) for gains in computational performance by defining a minimum arc length and maximum arc deviation from the real world data ROLANDS & ASSOCIATES Corporation

  16. Minimum Arc Length Figure 3. Minimum Arc Length Example The upper polyline, represented by 16 nodes and 25 arcs, was retrieved from the master database where, for illustration purposes, the nodes are 1-unit apart. If the user chooses a minimum arc length of 3-units, the result is the lower polyline reduced to 6 nodes and 5 arcs. There is no significant change to the original representation but will reduce the computational burden with respect to finding an optimal path. ROLANDS & ASSOCIATES Corporation

  17. Maximum acceptable arc deviation Maximum Arc Deviation Figure 4. Maximum Arc Deviation Example The polyline is abstracted further by the user specifying an acceptable maximum deviation from the original polyline.The resulting polyline has fewer nodes and is within the deviation specified for the scenario. ROLANDS & ASSOCIATES Corporation

  18. JTLS GIS Screenshots

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  23. Questions ROLANDS & ASSOCIATES Corporation

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