1	Microsoft TerraServer Tom Barclay, Microsoft Research Jim Gray, Microsoft Research
2	TerraServer Background Largest database on the Web (3 TB) Operational since June 1998 Public access to USGS topo maps (DRG) and aerial images (DOQ) Designed for basic computer systems and low speed communications Operated by Microsoft Corporation Hardware provided by Compaq Computer, Tape Library by ADIC Data provided by US Geological Survey
3	Research Objectives Public: Access to remote sensing data with no GIS expertise required Ubiquitous: No special hw/sw required by client Delivery: All OnLine/Internet Based, no tape or CD distribution Simple: Designed to be used by a “6^th grade geography student” Scale-up: creating multi-TB PC Server Availability: Test large MS Cluster system in a 24x7 situation Lights out: all operations & maintenance occurs remotely Easy: Minimal ops and dev staff Programmable: Meta & Imagery data accessible as a “web service”
4	TerraServer Home Page http://terraserver.microsoft.com
5	USGS Image Data Digital OrthoQuads 14 TB, 260,000 files uncompressed Digitized aerial imagery 88% coverage conterminous US 1 meter resolution < 10 years old Digital Raster Graphics 1 TB compressed TIFF, 65,000 files Scanned topographic maps 100% U.S. coverage 1:24,000, 1:100,000 and 1:250,000 scale maps Maps vary in age
6	TerraServer Growth
7	Original TerraServer Machine 2.6 TB RAID-5 Controller based SCSI Storage 324 9 GB hard drives 25’ Long, 7 tons
8	TerraServer SAN and Windows 2000 Cluster
9	Active Server Page Structure
10	TerraServer Schema
11	About Performance Optimized for Internet Use Use Stored Procedures for DB Access 1 “round-trip” to DB per web page 40 ms “budget” for ‘hard spatial query’ Use “dirty read / safe write” design to avoid lock contention Internet I/O model naturally “warms” the DB cache giving a performance boost to image retrieval Index Optimization All web page queries use an index Spatial search uses 1-level 2D “grid” index Flag field in Place gazetteer index reduces search domain by 80%
12	TerraServer: 1^st Generation Web App App
13	2^nd Generation Web App
14	3^rd Generation Web App
15	What is a Web Service?
16	TerraServer Web Services Retrieve meta-data on TerraServer imagery Query TerraServer Gazetteer Retrieve TerraServer Tiles (imagery) Simple Projection conversions Enables users/service providers to control user interface to TerraServer imagery Geo-coded data of well-known objects (points), e.g. Schools, Golf Courses, Hospitals, etc. Polygons of well-known objects (shapes), e.g. Zip Codes, Citys, etc. Intended to be “overlay” information for Terra-Tile-Service applications
17	.NET TerraService Architecture
18	TerraService Sample Apps Web Map Server OpenGIS “like” Landmarks layered on TerraServer imagery Standalone Client Application Visual Basic / C# Windows Form Access Web Services for all data
19	Production Applications
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21	Data Gateway Functional Overview
22	Soil Viewer accesses TerraService
23	Custom End Product
24	.NET Framework
25	Summary – Why .NET is Cool Your programmers will love it! Simpler programming model Language interoperability Much less work for object interoperability Powerful – Unifies interface to OS & Middleware Backwards compatible - Can call existing COM objects Fast execution Easy to learn and understand Tools – modern IDE and Debuggers Standards Based Based on Internet protocols - no more COM/CORBA wars! SOAP/XML supported by IBM, Microsoft, HP and also available with UNIX/Apache
26	Summary – Bottom Line Reduces cost of development and testing Simplifies integration between applications and system services Interoperates with legacy systems and components Enables cooperative computing between disparate hardware/software platforms Increases the power and sophistication of internet applications and services