The Land Analysis System (LAS) is an image analysis system designed to ingest, manipulate, and analyze digital image data and to provide the user with a wide spectrum of functions and statistical tools for image analysis. It is designed to support remote sensing, image processing, and geographic information systems (GIS) research and production efforts. LAS provides a flexible framework for algorithm development as well as processing and analysis of image data.
This document mainly describes LAS as implemented at the U.S. Geological Survey National Mapping Division's EROS Data Center (EDC). Other LAS environments may differ slightly in hardware configuration, system limitations, and operational procedures.
LAS as installed at the Pennsylvania State University has been
modified in several ways. These include:
The development of LAS started in the late 1970's when the National Aeronautics and Space Administration's (NASA) Goddard Space Flight Center (GSFC) identified the need for image processing software to investigate the radiometric and geometric characteristics of the new thematic mapper (TM) scanner, which was to be launched on Landsat-D, designated Landsat-4 following placement in orbit. This software package was known as the Landsat-D Assessment System, the forerunner of the Land Analysis System. In 1981, the Landsat-D Assessment System was modified to provide the basic software for the initial processing of Landsat-4 TM data until the production system was available. This Landsat support was referred to as TM Scrounge processing. In 1982, GSFC decided to expand the system capabilities and use it as a replacement for its current image processing system. This meant that a major development effort was needed to provide the required capabilities. In 1983, to reflect this change, the Landsat-D Assessment System was renamed the Land Analysis System or LAS.
LAS has been developed through a cooperative effort between the GSFC and the EDC under an agreement which dates back to 1983. As LAS continues to evolve, new capabilities, enhancements to old capabilities, and problem fixes have taken place. These include the capability to provide geographic coordinate information to the user, handle images up to a size of 50,000 lines by 50,000 samples and handle up to 256 spectral bands. These capabilities will allow global researchers to ingest AVHRR data sets, screen the data for clouds, and calculate vegetative indices such as normalized difference.
LAS is a system designed to provide the user with the tools necessary to perform image processing and analysis efficiently. Providing these tools, LAS encompasses each step--from ingestion of the data to the generation of output products.
The LAS application modules package is accessed by the user through the "Classic" (non-Xwindows) subset of the Transportable Applications Environment (TAE) interface. TAE allows the selection of the LAS modules and parameters through both menu and command language modes, accommodating both the first-time and the experienced user. Within the LAS structure, capabilities are available for the handling of image processing, data entry, tabular analysis, and vector data--with image processing at the core. Image processing modules comprise the majority of the LAS system and can be categorized into the areas of input, output, radiometric correction, geometric registration, signal processing, logicals, data transformation, classification, spatial analysis, nominal filtering, display manipulation, and miscellaneous utilities. Raster GIS capabilities also exist in the modules available under LAS. Tabular analysis may be done using the statistical packages and data base management systems that have been interfaced to LAS. LAS has been designed to be a highly transportable system and is available to users on computer systems which run the UNIX operating system. The latest version of LAS provides a more transportable public domain software system to scientists and analysts interested in digital image processing.
The purpose of this documentation is to provide the general LAS user with the information needed to use the LAS image analysis system. It is intended to be a user-oriented document as opposed to being a programmer-oriented document. For the first-time LAS programmer, this documentation should be referenced along with the LAS Programmer's Guide.
Hopefully, this document will provide the level of detail necessary to fully utilize the LAS facility. More than just a "how-to" document, this guide also provides the user with information such as utilizing the LAS environment, describing the user interface and syntax, and detailing data structures used in LAS. More detailed information on some of the components of LAS can be found from the references listed in Section 1.3.2.
1.3 Contacts and Documentation
There is not a main support facility for LAS. LAS is distributed with the understanding that there is no formal support.
As of early 2006, the USGS EROS Data Center site for downloading LAS was no longer operational. The Center for Environmental Informatics at PSU has placed a copy of the LAS distribution on a local FTP site, ftp://dbftp.essc.psu.edu/pub/code/las.
Questions about the PSU version of LAS should be directed to raw@essc.psu.edu.
Printed documentation is no longer available. This online documentation
is intended to include all the information previously provided by
printed manuals.