Proceedings of the Symposium on Global and Environmental Monitoring: Proceedings of the Symposium on Global and Environmental Monitoring

Bibliographic data

Multivolume work

Persistent identifier:: 856665355

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts ; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856665355

Language:: English

Document type:: Multivolume work

Volume

Persistent identifier:: 856669164

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Scope:: XIV, 912 Seiten

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856669164

Illustration:: Illustrationen, Diagramme, Karten

Signature of the source:: ZS 312(28,7,1)

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: International Society for Photogrammetry and Remote Sensing, Commission of Photographic and Remote Sensing Data

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: [WP-3 FOREST INVENTORY APPLICATIONS]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: USE OF DIGITAL SATELLITE DATA FOR STAND DELINEATION AND ESTIMATION OF STAND VARIABLES BY REGRESSION ANALYSIS AND FIELD INVENTORY. Olle Hagner

Document type:: Multivolume work

Structure type:: Chapter

USE OF DIGITAL SATELLITE DATA FOR STAND DELINEATION AND ESTIMATION OF STAND VARIABLES BY REGRESSION ANALYSIS AND FIELD INVENTORY 01le Hagner Dept, of Biometry and Forest Management, Remote Sensing Laboratory, Swedish University of Agricultural Sciences, S-901 83 Umea, Sweden ABSTRACT The method described is based on integrated use of digital satellite data, National Forest Inventory (NFI) sample plots, map information, and subjective field inventory. Forest stands are delineated by using a digital region growing technique called "t-ratio segmentation" and SPOT satellite data. The segmentation is guided by digitized map information on landuse and administrative regions. Stand characteristics are estimated for each stand by combining estimates obtained from both satellite data and field inventory. NFI sample plots and corresponding spectral signatures are used to construct regression functions for esti mation of stand variables. The method was evaluated at five separate test sites in northern Sweden. The t-ratio segmentation method produced results similar to visual interpretation of aerial photos and field checking. The accuracy of stand data estimation was comparable to subjective field inventory. A substantial improvement in estimate precision was obtained when combined estimates were calculated from both satellite data and field inven tory. Key Words: SPOT, Landsat TM, segmentation, region growing, stand delineation, forest inventory, estimation of stand characteristics. 1 INTRODUCTION 1.1 Background 1.1.1 Stand delineation and inventory methods used in practice. The basic unit in Swedish forest management planning is the forest stand, which is a homogeneous region of about 1-20 hectares in size. Several adjacent stands with similar charac teristics may be grouped into treatment units, or compartments. Stands are delineated by means of visual interpretation of black and white aerial photos, usually at the scale of 1:30 000 or 1:20 000. The result is checked and corrected during field inventory. Stand characteristics are normally estimated by means of ocular field methods, supported by a few relascope measurements at subjectively selected spots within each stand. After field inventory, the final delineation is transferred to a forestry map with orthophoto background and, in some cases, the result is digitized and stored in a GIS. Although field inventory constitutes the major part of forest mapping costs today, very few additional sources of information are used in the estimation of stand characteristics. 1.1.2 The thematic classification approach. Several attempts to use the "classic" satellite remote sensing approach for forest mapping, i.e. supervised thematic classification, have been made in the Nordic countries. The results, however, have usually been of no or limited value to foresters for management planning. One of the main reasons is that the information needed is standwise estimates of several stand character istics rather than discrete pixel by pixel class information. Most of the important stand variables are continuous, e.g., volume/hectare, mean age, mean diameter, tree species mixture etc. This information can not be expressed by a few discrete classes, without large approximations. Some other limitations of the classic approach are: (1) The procedure of selecting appropriate training samp les is laborious and often subjective. (2) Dis crete class definitions are difficult to match with other sources of information. 1.1.3 The Finnish approach. Several studies in Finland have proposed the use of digital satellite data for standwise estimation of continuous stand variables. Poso et. al. (1987) used satellite data, digitized stand boundaries, and clustering techniques in a stratified two-phase sampling design. Tomppo (1986) used National Forest Inven tory (NFI) sample plots and corresponding spectral signatures from Landsat TM to construct regression functions. They also used digital satellite data for delineation of homogeneous regions. The results were very promising and indicated that stand characteristics could be estimated almost as accurately with satellite data, as with manual ground-only methods. They also demonstrated the importance of using map information in the analys is. The segmentation technique used, called "di rected trees" (Narrendra & Goldberg, 1985), was considered very promising, although some improve ments were needed. 1.2 Objectives Inspired by the Finnish results, a project was started in 1986 at the Remote Sensing Laboratory in Umea. The aim was to develop a new integrated inventory method combining, via statistical tech niques the potentials of satellite remote sensing, field inventory methods and geographic information systems (GIS). The objectives of this study were to define the method and to test the main parts; the computer delineation of stands and the esti mation of stand variables. 2 MATERIAL AND METHODS 2.1 Outline of the integrated inventory design The basic idea behind the method is to enhance existing inventory methods by using computer support to derive new information from digital satellite data and other sources of information. The methods should be implementable on mobile workstations and capable of being operated by field inventory personnel. 2.1.1 Stand delineation. Segmentation tech niques and high resolution satellite data are used (Tomppo 1986), (Hagner 1989) for delineation of homogeneous stands of approximately 0.5-5 hectares in size. The delineation is guided by map 393

Access restriction

Copyright

fullscreen: Proceedings of the Symposium on Global and Environmental Monitoring (Part 1)

Multivolume work

Volume

Chapter

Chapter

Table of contents

Cite and reuse

Volume

Chapter

Image

Image fragment

Citation links

Citation recommendation