Transcript GeoFusion, Inc. Digital Earth Visualization Paul Hansen [email protected] Chuck Stein [email protected] www.geofusion.com GeoFusion, Inc. • Santa Cruz based software technology company • Based on Paul Hansen’s work with.

GeoFusion, Inc.
Digital Earth Visualization
Paul Hansen
[email protected]
Chuck Stein
[email protected]
www.geofusion.com
GeoFusion, Inc.
• Santa Cruz based software technology company
• Based on Paul Hansen’s work with digital earth
rendering
• Goals:
– Create core technology for the GeoWeb
– Put an interactive digital earth on everyone’s desktop
• License software – GeoMatrix® Toolkit (SDK)
• Custom application development
• Rendering services
Accelerating Digital Earth Development
• Early choice: application vs. toolkit
• Digital Earth Application Programmer’s Interface (API)
allows for a multitude of applications and uses
• Promote data sharing with non-proprietary projection and
data format
• Provide customers the ability to use the
Earth as an interface to desired functionality
• Platform independence
GeoMatrix®
Digital Earth System
• The GeoMatrix Toolkit
– An Application Programmer’s Interface (API) for building digital
Earth applications
• Uses a unique projection and global tessellation system that
facilitates tile generation, texture mapping, & rendering
• Tile generation and data “format” that supports:
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Multi-resolution representation of source data
Fast look-up database speeds demand paging of data tiles
Valid/invalid (transparent) pixel determination
Compression and format options
GeoMatrix®
Digital Earth System
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Renders vast amounts of data
Fast inclusion of data at run-time
Real-time scene generation
Continuous level-of-detail while zooming
Platform independent, OpenGL based graphics
Low cost hardware, highly optimized software
Small libraries (DLLs: 50-200k)
API allows for rapid development of applications
Requirements
• 128 Mb RAM
• 3D accelerated graphics
• OpenGL
Native Data Types
Multi-resolution, tiled representation of:
– Imagery
– Terrain
– Vector
– Annotation
GeoMatrix® Toolkit Features
• Fully interactive, high performance 3D digital
Earth platform
• Visualization of image, terrain, vector, &
annotation data
• Continuous level-of-detail while zooming
• Manages a vast number of datasets
simultaneously; attach and detach at will
• Platform independent C++, object oriented API
GeoMatrix® Toolkit Features (cont.)
• Draw your own content into the GeoFusion
rendered world:
– Text, lines, 3D models, etc.
• Demand paging of local or remote data tiles
• Blend between image data layers
• Animate events over time
• Output arbitrary resolution images or frames for
movies
GeoMatrix Toolkit Modules
Tile
Generation
3D
Navigation
Rendering
(visualization)
Tile I/O
(data servers)
GeoMatrix Applications
scene 1
scene 2
Multiple
scenes/viewports
globe 1
globe 2
Coincident,
concentric or offset
dataset 1
dataset 2
dataset 3
Image, Terrain,
Vector, Annotation
1km NASA Modus
1km pseudo-color
bathymetry & terrain
6 inch aerial imagery draped over
LIDAR elevation data.
70 cm aerial imagery
CIA map blended with satellite imagery over terrain.
Yosemite, California:
8m black & white DOQ imagery on 10m DEM
1km global bathymetry and terrain
Example application of satellite models drawn on
top of GeoFusion rendered Earth.
ESRI’s ArcGlobe
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Available in ArcGIS 3D Analyst extension
Tremendous increase in performance
Interactive, supports layers, 3D models, etc.
GIS is moving from flatland to the “globe”
Allows viewing most data in ESRI geodatabase
Prepares data on-the-fly, then caches tiles
GeoMatrix core concepts
1. Tiled, multi-resolution data packaging. Tiles have a consistent
size with a definite upper-bound, allowing them to be easily
moved around and assembled into a view.
2. Unique tiling system (GeoMatrix) for the Earth globe. Hybrid
system--combination of geographic projection and square polar
projection. Smooth transitions across domain boundaries.
Efficient treatment of polar singularities.
GeoMatrix core concepts (cont.)
3. Fast recursive subdivision and fast, aggressive culling of
"geometry“ (surface parts) outside the viewing window.
4. Fast and fine-grained level-of-detail (LOD) calculation allows
the minimal collection of needed tiles to be accessed.
5. Introduction of higher-resolution data before it is easily visible.
"New“ data appears "between" previously seen data rather than
replacing it, and, for terrain data, gradually morphs to its full
extent.
GeoMatrix core concepts (cont.)
•6. Fast data coordination and rendering allow a realistic Earth to
be a 3D canvas for other kinds of data visualization. The
GeoMatrix provides a spherical coordinate space infrastructure.
•7. Creation of a set of software modules that make this
technology available to a wide variety of applications developers
through a set of innovative programming interfaces (APIs). The
GeoMatrix Toolkit.
Globe Faces
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Polar Projection
0ºE
QUADRANT 2
15ºW
30ºW
QUADRANT 3
QUADRANT 1
45ºW
80ºN
60ºW
70ºN
60ºN
75ºW
QUADRANT 0
50ºN
90ºW
Globe Mapping
top view
full globe
Polar/Equatorial Congruency
Mapping Function
90oN
0.0
P
P
45oN
1.0
180oW
135oW
PX = PX * PY
PY = PY
90oW
-1.0
0.0
1.0
Coordinate Spaces
•“Face” coordinates—normalized Cartesian coordinates
per-face.
•“Tile” coordinates—quad-tree indexing: F,L,R,C
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globe face index
recursion level number
row index
column index
Coded Vertexes
• Peano coding for vertex locations. Except:
• no interleaved bits
• LSB is dedicated “1.0” bit
• location is within a particular tile
• Fast conversion between face coordinates.
• Combine vertex coding with tile coordinates.