1 / 21

Introduction to Field Data in Remote Sensing

This chapter provides an introduction to field data in remote sensing, covering information on field radiometry, handheld spectroradiometers, GPS, and geographic sampling.

vargo
Download Presentation

Introduction to Field Data in Remote Sensing

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 5 Field Data Introduction to Remote Sensing Instructor: Dr. Cheng-Chien Liu Department of Earth Sciences National Cheng Kung University Last updated: 27 October 2004

  2. Outline • Introduction • Information of field data • Field radiometry • Tutorial/demonstration of handheld spectroradiometer • Basic radiometric quantities and definitions • Location information • Tutorial/demonstration of handheld GPS • Geographic sampling

  3. Introduction • Field data • Necessary for remote sensing • Establish relationship between ground truth and imagery • Validation • Evaluation • Expensive • Purpose-oriented • Content • Method

  4. Information of field data • Attributes/measurements of ground conditions • Nominal data • e.g. crop identification, land use, … • Biophysical data • Moisture content, Leaf area index (LAI), … • Radiometry data • Location and size • Time and date • Ancillary data • Weather, illumination, calibration of instrument, persons who collect data

  5. Field radiometry • Handheld spectroradiometer • Constitution (Fig 1.14a or see Campbell 2002 Fig 12-4) • Pointing device • Fiber-optical cable • Measuring unit • Detector • Filter • Display unit • Data log • Measurement • Radiance • Reflectance

  6. Tutorial/demonstration of handheld spectroradiometer • Software installation • Hardware installation • Calibration • Data log • Data processing • Implementation • (Fig 1.14b and Fig 1.15, or see Campbell 2002 Fig 12-9)

  7. Basic radiometric quantities and definitions • Spherical coordinate • Measurement of radiance L • Definition of L • Measurement of planar irradiance E • Definition of E • Measurement of scalar irradiance E0 • Definition of E0 • Definition of reflectance R = Eu/Ed • Definition of remote sensing reflectance Rrs =Lu/Ed

  8. Locational information • Observations need locational information • Method • Reference to distinctive landmarks • Valid for well-mapped regions • Global Positioning System (GPS)

  9. Global Positioning System • Satellite • Orbit • Working principle • Receiver • Accuracy • Selective availability (SA)

  10. Geographic sampling • Terminology • Observation • Sample • Three considerations • Number of observations • Sampling pattern • Spacing of observations

  11. Geographic sampling (cont.) • Number of observations • The larger the sample size, the closer to the actual values • Minimum number assigned to each class • Sampling pattern • Simple random sampling pattern • Stratified random pattern • Systematic patterns • Systematic stratified unaligned pattern • Cluster sampling • Spacing of observations

  12. Homework • We are going to employ the handheld spectroradiometer and GPS receiver to collect field data of vegetation in the watershed of Chen-Yo-Lan River. Please help us to integrate these instruments on(1) Shoulder(2) Suzuki grand Vitara (3) unmanned helicopter

  13. Homework (cont.) • The reflectance of a standard white board is given in Table 1. The field measurements of the standard white board and the sample are shown in Table 2, respectively. Please use this information to calculate the reflectance of the sample. Table 1 Table 2

  14. Source

  15. Fig 2.3.1 Fig. 2.3.1 Definition of the polar coordinates (q,f) and of the upward (Xu) and downward (Xd) hemispheres of directions. Reprint from Figure 1.3 in (Mobley 1994).

  16. Fig. 2.3.2 Fig. 2.3.2 Schematic design of an instrument for measuring un-polarized spectral radiance. Reprint from Figure 1.5 in (Mobley 1994).

  17. 2.3 Basic radiometric quantities and definitions (cont.) • Radiance L:

  18. Fig. 2.3.3 Fig. 2.3.3 Schematic design of an instrument for measuring un-polarized spectral downwelling planar irradiance. Reprint from Figure 1.6 in (Mobley 1994).

  19. 2.3 Basic radiometric quantities and definitions (cont.) • Downwelling planar irradiance Ed:

  20. Fig. 2.3.4 Fig. 2.3.4 Schematic design of an instrument for measuring un-polarized spectral downwelling scalar irradiance. Reprint from Figure 1.7 in (Mobley 1994).

  21. 2.3 Basic radiometric quantities and definitions (cont.) • Downwelling scalar irradiance E0d:

More Related