PE&RS November 2003

Cover Image

Image provided by Pictometry International Corp., a leading provider of geo-referenced, oblique and ortho imagery information systems. Pictometry utilizes digital sensors coupled with inertial measurement and airborne GPS to capture data without the need for ground control. The day after Hurricane Isabel touched ground, Pictometry was notified by its customer that they needed images of the hurricane’s damage. The company scheduled, flew, and captured highresolution images (6 inch GSD) and delivered them to the customer exactly one week after the storm hit. Pictometry enables users to access up to 12 different views of any property, building, highway, or feature in a county and/or state. With only minutes of training, users can obtain a wide range of measurements on building and property assets within the images. Over 80% of Pictometry images are metric oblique. The end result is an easy-to-use information system for community planning, assessment, development, public safety, and homeland security applications. Using Pictometry’s Change Analysis software, rescue and relief agencies can compare disaster images with imagery taken by Pictometry of the same area prior to the incident. For more information call 585-486-0093. Pictometry images can be viewed at www.pictometry.com/pers.asp.

Peer-Reviewed Articles (Click the linked titles to see the full abstract)

1225 A Comparison of Activation Functions for Multispectral Landsat TM Image Classification
Coskun Özkan and Filiz Sunar Erbek

The main objective of the study was to compare linear, sigmoid, and tangent hyperbolic activation functions through the one- and two-hidden layered MLP neural network structures trained with the scaled conjugate gradient learning algorithm, and to evaluate their perfornances for a multispectral Landsat TM imagery hard classification problem.

1235 Recovery of Systematic Biases in Laser Altimetry Data Using Natural Surfaces
Sagi Filin

An error recovery model that is based on modeling the system errors and on defining adequate control information is presented.

1243 Investigating SeaWinds Terrestrial Backscatter: Equatorial Savannas of South America
Perry J. Hardin and Mark W. Jackson

Backscatter of equatorial savannas in northern South America was statistically modeled as a function of vegetation, precipitation, and soils.

1255 Grasslands Discriminant Analysis Using Landsat TM Single and Multitemporal Data
Xulin Guo, Kevin P. Price, and James Stiles

Land management practices (CRP, grazing, and haying) applied on cool- and warm-season grasslands could be discriminated using multitemporal Landsat Thematic Mapper data at a moderate accuracy level (67.6 percent).

1263 Estimating Tree Crown Size from Multiresolution Remotely Sensed Imagery
Conghe Song and Curtis E. Woodcock

The theory and a simple analytical model are presented to estimate tree crown size of a forest stand using sills of variograms from images at two spatial resolutions.

1271 Evaluating the Performance of Spatially Explicit Models
Robert Walker

Statistical approaches to evaluating the performance of spatially explicit models are described.

1279 Strategies for Integrating Information from Multiple Spatial Resolutions into Land-Use/ Land-Cover Classification Routines
DongMei Chen and Douglas Stow

Three strategies for integrating image information from different spatial resolutions into classification routines are developed and tested.

1289 Automated Change Detection for Updates of Digital Map Databases
Thomas Knudsen and Brian P. Olsen

The change detection algorithm uses vector and spectral data as input to an unsupervised spectral classification method which controls a subsequent Mahalanobis classification step.

Announcements
1210 ISPRS XXth Congress
1218 Call for Papers — PE&RS Special Issue on Mobile Mapping Systems

Columns & Updates
1205 Grids & Datums — Republic of Zimbabwe
1211 Headquarters News
1215 Industry News

Departments
1214 New Member List
1219 Who’s Who in ASPRS
1220 Sustaining Members
1222 New Sustaining Member
1222 Advertiser Index
1223 Forthcoming Articles
1224 Calendar
1288 Instructions to Authors
1297 Classifieds
1299 Bookstore
1304 Professional Directory
1308 Membership Application

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