Can You Trust Google Earth?

Math and Computer Science Department Seminar

Wheaton College

Problem:

Get directions to Osseo Circle, Lincoln, NH

MapQuest

MapQuest

MapQuest

Whoops!

Database problem

Google Maps

Same problem!

Google Earth

Dear Ol' Wheaton

Google Earth

Something's amiss!

Google Maps

Huh?

Google Earth - Terrain

Terrain Storage: DEM

DEM = Digital Elevation Model

Regular grid of elevation points

Creating a DEM

Traditional

Spot Heights

Stereo Aerial Photography

AutomatedStereo Matching

Convert toDLG

Convert toDEM

Manual Contouring

Errors!

Creating a DEM

Traditional

Spot Heights

State of the Art

Stereo Aerial Photography

AutomatedStereo Matching

Convert toDLG

Convert toDEM

Manual Contouring

Satellite

SAR

Plane

LiDAR

InternalRepresentation

Convert toDEM

Errors!

DEM Error Viewer

Error Visualization

Error Visualization