Compro Simulation
Database GenerationCustom Terrain Database (TDb)
Compro creates geospecific and generic custom Terrain Databases (TDb) using elevation, cultural, and imagery data in printed and machine readable formats. While this description focuses on visual databases, radar and electro-optic databases can be created by optionally encoding material property data in the the TDb at the time it is built.
A typical TDb is a 2.5 degree by 2.5 degree area or approximately 150 nautical miles per side. A generic TDb contains 30% water and coastline. The TDb combines the following Fidelity Regions:
High:
Includes lines of communication (roads, rivers, railroads and power lines), city faces, tree blocks, obstructions, towers, bridges and dams to the level typically captured on 1:250,000 JOG charts.
Medium:
Includes lines of communication (roads, rivers, railroads and power lines) city faces, tree blocks, obstructions, towers, bridges and dams to the level typically captured on 1:500,000 TPC charts.
Low:
Includes 2D water, land and the defining coastline.
Each TDb contains three high fidelity air airfields and up to four generic airfields. High fidelity airfields are modeled using FLIP charts, airfield blueprints, and photographs and have the following features:
| Runway polygons with accurate color and texture |
| Major buildings (terminals and/or hangars) as identified on FLIP charts |
| Runway markings (runway numbers, center/edge lines, touchdown zones, etc.) |
| Touchdown skid marks |
| Taxiways and aprons |
| Centerline Lights |
| Runway Edge Lights |
| Strobe Lights |
| Approach Lights |
| Taxi/Touchdown Zone Lights |
| Threshold Lights |
| VASI Lights |
| REILs |
| Beacon |
Each high fidelity airfield is surrounded by a 5 nautical mile circle of High Fidelity features which in turn are surrounded by a 20 nautical mile circle of Medium Fidelity features. The remainder of the area is Low Fidelity. Generic airfields have a designated orientation, altitude, and runway length and generic buildings and transition features. Compro tailors the border between one fidelity region and another to ensure a smooth transition. Lines of communication do not end unnaturally or change abruptly as is common when multiple data sources are used. Where necessary we reduce the number and complexity of features to ensure overall visual system performance budgets.
Source Data is obtained from:
| National Imagery and Mapping Agency (NIMA) NOTE—Higher accuracy data sources are restricted to military use only. |
| United States Geological Survey (USGS) |
| National Oceanic and Atmospheric Administration (NOAA) |
| Commercial suppliers of geospecific imagery and textures |
Elevations are the height above mean sea level. This information can be provided in a grid, a Triangulated Irregular Network (TIN), or a point. Typical forms are:
| Digital Elevation Model format (DEM) ranges from 1:250K to 1:50K scale. The lower accuracy is available for most of the
|
| Digital Terrain Elevation Data (DTED) ranges from 1km to 30m post spacing. |
Cultural Data or Features are the natural and man-made semi-permanent objects found on the earth, i.e., buildings, rivers, forests, roads, lake and ocean boundaries. This information can be provided as vector data of points, lines, and polygons. Typical forms are:
Name Description Scale Type
- DFAD Digital Feature Analysis Data 1:250K Electronic
- DLG Digital Line Graph 1:100K & 1:2M Electronic
- DCW Digital Chart of the World 1:1M Electronic
- JNC Jet Navigation Chart 1:2M Paper
- ONC Operational Navigation Chart (AKA World Aeronautical Chart) 1:1M Paper
- TPC Tactical Pilotage Chart (AKA Sectional Chart) 1:500K Paper
- JOG Joint Operations Graphic (AKA Terminal Area Chart) 1:250K Paper
- TLM Topographic Line Map 1:50K Paper
- FLIP Flight Information Publication (AKA Airport/Facilities Directory) varies Paper
Imagery or Geotexture refers to aerial or satellite photography that covers a region of interest or specific textures that represent the face of a building or some other structure of significance. Typical formats are GeoTiff, GIF and JPEG. Imagery data is available from a number of government and private sources. For generic TDbs, Compro uses generic textures for cityscapes, runways, roads, etc.
Models are the buildings, structures, and objects in the database that are represented in a 3D format as opposed to a imagery picture draped over elevation posts. Typical file formats are, MultiGen .flt, and Centric/Coryphaeus .dwb. Models can be fixed in the TDb or perturbed and moved under the control of simulation software. They normally have three to five different Levels of Detail (LOD). Compro uses our own custom models and catalog models from Viewpoint DataLabs. Typical characteristics of moving models are:
Types Polygons (High LOD) Aircraft Carrier* with the following lighting:
- Runway/Deck Edge
- Centerline/Line-Up
- Approach/Dropline
- Strobe
- Threshold
- Touchdown Zone
- Deck Status
- FLOLS/Meatball
- DATUM
- Wave-Off
- Anti-Collision/Position
- ~1000
- Land, Sea, Air and Ground Vehicles 300 - 500
- Surface-to-Air, Air-to-Air and Air-to-Ground Weapons ~1
*1: Generic aircraft carrier for low fidelity applications includes limited lighting effects.
