6 Future Applications
Accurate and timely land use data, and land use change data, form important
components of addressing land use planning and land use policy for the twentyfirst century. Remote sensing provides one of the most important tools for acquiring
and analyzing such data. In this context, we can expect changes to current strategies. Changes may promote integration of information and target acquisition of
imagery to acquire land use data of smaller regions at greater spectral and spatial
detail. For example, investigations of the urban heat island can benefit from
integration of land use data with detailed thermal data to better define the role of
land use in urban temperatures (e.g., see [53, 54]). Likewise, hyperspectral data, not
normally employed for land use survey, can play a role in detecting regions where
there is a legacy of contaminated soils, environmental hazards, and related risks to
public health.
This section will explore three nascent technologies for remote sensing of land
cover—Lidar, hyperspectral images, and unmanned aerial systems. The technologies, themselves, are not new, but researchers are exploring new applications in the
context of land use/land cover assessment.
6.1 Lidar
Lidar (light detecting and ranging) is a form of active remote sensing. Lidar
technology is based on applications of lasers (Fig. 10). Light is generated by the
laser (1) which travels through fiber optic cables to a rotating mirror (2). The light is
directed through bundled optical cables (3), which are twisted to provide a directed
beam through lenses to the feature(s)/object(s) of interest. Reflected light is
returned to the sensor (4), through a separate set of bundled fiber optic cables, to
a second rotating mirror, and then transmitted (5) via fiber optic cables to the
receiver (6). The transmission of the laser beam and the registration of the returns
are controlled by the electronics.
The Lidar sensor records the time it takes for the returned (reflected) light to
reach the sensor and translates the time delay as distance to the object. After
processing of the returns, in aerial systems this distance then determines the height
of that particular feature above ground. In ground-based (terrestrial) systems, the
measurement is the distance from the sensor. Analysis of these distances, using
appropriate software, results in surface elevation models, forest modeling, and other
applications. The Lidar sensors are also equipped with geographic referencing
equipment so the returns can be spatially located on the Earth’s surface. Lidar
sensors can be placed on aircraft, satellites, in ground-based vehicles, or on a
stationary tripod on the ground (Fig. 11).
Because Lidar transmits light energy, as photons, the pulses penetrate even the
smallest openings. The number of pulses per second and time delays between pulses
Land Use/Land Cover Monitoring and Geospatial Technologies: An Overview
21
Accurate and timely land use data, and land use change data, form important
components of addressing land use planning and land use policy for the twentyfirst century. Remote sensing provides one of the most important tools for acquiring
and analyzing such data. In this context, we can expect changes to current strategies. Changes may promote integration of information and target acquisition of
imagery to acquire land use data of smaller regions at greater spectral and spatial
detail. For example, investigations of the urban heat island can benefit from
integration of land use data with detailed thermal data to better define the role of
land use in urban temperatures (e.g., see [53, 54]). Likewise, hyperspectral data, not
normally employed for land use survey, can play a role in detecting regions where
there is a legacy of contaminated soils, environmental hazards, and related risks to
public health.
This section will explore three nascent technologies for remote sensing of land
cover—Lidar, hyperspectral images, and unmanned aerial systems. The technologies, themselves, are not new, but researchers are exploring new applications in the
context of land use/land cover assessment.
6.1 Lidar
Lidar (light detecting and ranging) is a form of active remote sensing. Lidar
technology is based on applications of lasers (Fig. 10). Light is generated by the
laser (1) which travels through fiber optic cables to a rotating mirror (2). The light is
directed through bundled optical cables (3), which are twisted to provide a directed
beam through lenses to the feature(s)/object(s) of interest. Reflected light is
returned to the sensor (4), through a separate set of bundled fiber optic cables, to
a second rotating mirror, and then transmitted (5) via fiber optic cables to the
receiver (6). The transmission of the laser beam and the registration of the returns
are controlled by the electronics.
The Lidar sensor records the time it takes for the returned (reflected) light to
reach the sensor and translates the time delay as distance to the object. After
processing of the returns, in aerial systems this distance then determines the height
of that particular feature above ground. In ground-based (terrestrial) systems, the
measurement is the distance from the sensor. Analysis of these distances, using
appropriate software, results in surface elevation models, forest modeling, and other
applications. The Lidar sensors are also equipped with geographic referencing
equipment so the returns can be spatially located on the Earth’s surface. Lidar
sensors can be placed on aircraft, satellites, in ground-based vehicles, or on a
stationary tripod on the ground (Fig. 11).
Because Lidar transmits light energy, as photons, the pulses penetrate even the
smallest openings. The number of pulses per second and time delays between pulses
Land Use/Land Cover Monitoring and Geospatial Technologies: An Overview
21