#1 - Introduction to Remote Sensing Review Questions
Terms in this set (16)
What is an in situ data collection?
Measurements made at the actual location of the object or material measured, in contrast to remote sensing
Give an example of in situ data collection
A scientist collecting leaf-area-index (LAI) measurements of soybeans using a ceptometer that measures the number of "sunflecks" that pass through the vegetation canopy. The measurements are made just above the canopy and on the ground below the canopy
How can error be introduced during the in situ data collection process- intrusive 1?
Unless great care is exercised, the scientist can actually change the characteristics of the phenomenon being measured during the data collection process.
How can error be introduced during the in situ data collection process- intrusive 2?
Similarly, a scientist collecting a spectral reflectance reading could inadvertently step on the sample site, disturbing the vegetation canopy prior to data collection.
How can error be introduced during the in situ data collection process - method-produced error?
Scientists could collect data in the field using biased procedures such as the use of a biased sampling design or the improper use of a piece of equipment. Also, the data collection measurement device may be calibrated incorrectly.
What are some advantages of remote sensing-1?
1. Remote sensing is unobtrusive if the sensor passively records the EMR reflected or emitted by the object of interest. Passive remote sensing does not disturb the object or area of interest.
What are some advantages of remote sensing-2?
2. Remote sensing devices may be programmed to collect data systematically, such as within a 9 9 in. frame of vertical aerial photography. This systematic data collection can remove the sampling bias introduced in some in situ investigations.
What are some advantages of remote sensing-3?
3. Under controlled conditions, remote sensing can provide fundamental biophysical information, including x,y location, z elevation or depth, biomass, temperature, and moisture content.
What are some advantages of remote sensing-4?
4. Remote sensing-derived information is now critical to the successful modeling of numerous natural processes, such as water-supply estimation; eutrophication studies, and nonpoint source pollution; and cultural processes such as land-use conversion at the urban fringe, water-demand estimation, and population estimation.
What are some limitations of remote sensing-1?
1.The greatest limitation is that it is often oversold. Remote sensing is not a panacea that provides all the information needed to conduct physical, biological, or social science research. It provides some spatial, spectral, and temporal information of value in a manner that we hope is efficient and economical
What are some limitations of remote sensing-2?
2.Human method-produced error may be introduced as the remote sensing instrument and mission parameters are specified. Human beings select the appropriate remote sensing system to collect the data, specify the various resolutions of the remote sensor data, calibrate the sensor, select the platform that will carry the sensor,
determine when the data will be collected, and specify how the data are processed.
What are some limitationaof remote sensing-3?
3.Powerful active remote sensor systems that emit their own electromagnetic radiation (LIDAR, RADAR, SONAR) can be intrusive and affect the phenomenon being investigated. Additional research is required to determine how intrusive these active sensors can be.
What are some limitationaof remote sensing-4?
4. Remote sensing instruments may become uncalibrated, resulting in uncalibrated remote sensor data.
What are some limitationaof remote sensing-5?
5. Remote sensor data may be expensive to collect and analyze. Hopefully, the information extracted from the remote sensor data
justifies the expense.
What are the steps to the Remote Sensing Process?
Identifying the Problem; Statement of the Problem
What are the four sensor resolutions that must be determined before acquiring data?
Spatial, Spectral, Temporal, and Radiometric