USGS ScienceSearch

USGS · 70113227

A comparative study of linear and nonlinear edge finding techniques for Landsat multispectral data

Abstract

Several numerical methods were computerize in order to evaluate edge finding techniques for accuracy, versatility and computer time and cost. The study was preformed primarily to select edge detection operators which will be used to do spatial correlation between images for image registration of Landsat Multispectral Scanner (MSS) scenes. These method are also used to enhance and discriminate certain types of boundaries; such boundaries or edges are related to geologic structure, topographic relief, albedo and color changes. Application of these techniques has an aid in geologic and geographic remote sensing is evaluated. Landsat scenes of Washington, D.C. and Death Valley were chosen to test the applicability of techniques both in arid desert and vegetation--water--urban cases.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Robert Shaw, Lynda Sowers, Ellen Sanchez. 1981. A comparative study of linear and nonlinear edge finding techniques for Landsat multispectral data. https://pubs.usgs.gov/publication/70113227

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

Some thoughts on cartographic and geographic information systems for the 1980's

The U.S. Geological Survey is adopting computer techniques to meet the expanding need for cartographic base category data. Digital methods are becoming increasingly important in the mapmaking process, and the demand is growing for physical, social, and economic data. Recognizing these emerging needs, the National Mapping Division began, several years ago, an active program to develop advanced digital methods to support cartographic and geographic data processing. An integrated digital cartographic database would meet the anticipated needs. Such a database would contain data from various sources, and could provide a variety of standard and customized map and digital data file products. This cartographic database soon will be technologically feasible. The present trends in the economics of cartographic and geographic data handling and the growing needs for integrated physical, social, and economic data make such a database virtually mandatory.

Pecora VII Symposium

Classification systems for natural resource management

Resource managers employ various types of resource classification systems in their management activities such as inventory, mapping, and data analysis. Classification is the ordering or arranging of objects into groups or sets on the basis of their relationships, and as such, provide the resource managers with a structure for organizing their needed information. In addition of conforming to certain logical principles, resource classifications should be flexible, widely applicable to a variety of environmental conditions, and useable with minimal training. The process of classification may be approached from the bottom up (aggregation) or the top down (subdivision) or a combination of both, depending on the purpose of the classification. Most resource classification systems in use today focus on a single resource and are used for a single, limited purpose. However, resource managers now must employ the concept of multiple use in their management activities. What they need is an integrated, ecologically based approach to resource classification which would fulfill multiple-use mandates. In an effort to achieve resource-data compatibility and data sharing among Federal agencies, and interagency agreement has been signed by five Federal agencies to coordinate and cooperate in the area of resource classification and inventory.

Pecora VII Symposium

Digital elevation data as an aid to land use and land cover classification

Elevation data is generally associated with topographic maps and expressed by contours and spot elevations. However, elevation data is also essential to the proper classification of land use and land cover by remote sensing techniques. Absolute elevation governs various types of vegetative growth as does the degree and direction of slope. However, the effect of terrain aspect (slope and direction) on reflectance is of even greater significance. The angular relationship of a surface to the sun can significantly effect the radiometric response. For flat areas this effect is contract but she slopes are involved they must be considered if automated classification is to be applied. To overcome the terrain aspect effect, rating of multi-spectral responses is used in an attempt to eliminate the terrain aspect. However, this is only partially effective and when the terrain aspect controls group cover it is of little or no value. The proper solution to the aspect problem is to obtain and utilize suitable digital elevation data in conjunction with remote sensor response. The relationship of the aspect to the response can be developed by theory of empirical test and when properly applied can neutralize the aspect response. Then the classification of land use and land cover can proceed without the unwanted radiometric anomalies of terrain aspect. In relatively well mapped areas such as the United States and Europe, digital data can be developed from topographic maps or from the stereo aerial photographic movie. For poorer mapped areas (which involved most of the world's land areas), a satellite designed to obtain stereo data offers the best hope for a digital elevation database. Such a satellite, known as Mapsat, has been defined by the U.S. Geological Survey. Utilizing modern solid state technology, there is no reason why such stereo data cannot be acquired simultaneously with the multispectral response, thus simplifying the overall problem of land use and land cover classification.

Pecora VII Symposium