Remote sensing technology and its application?

Remote sensing technology and its application

(1) Acquisition of Remote Sensing Images

(1) sensor: the instrument for detecting and recording electromagnetic waves is called a sensor, and it is called aerial remote sensing when it is installed on an airplane; Installed on an artificial earth satellite, it is called space remote sensing.

(2) Remote sensing images: Remote sensing images can be obtained by photography or scanning.

(3) Technical indicators of remote sensing images:

Spectral range: the maximum range of received and recorded electromagnetic wave wavelengths. The selected wavelength range is called "atmospheric window".

Spectral resolution: the smallest wavelength range that can be resolved on the influence diagram.

Image coverage: the surface space coverage of the scene image.

Geometric resolution of image: the smallest feature size that can be resolved on the image map.

Time phase: the specific time of remote sensing information imaging.

(2) Common remote sensing images

(1) Aerial photo outside the rainbow: high color saturation, strong contrast, good definition and high resolution for vegetation and water (vegetation is red).

(2) Thermal infrared scanning image: it can be imaged day and night, and the resolution of ground temperature can reach 0. 1-0.5 degrees, which is often used for urban heat island analysis.

(3) Microwave radar image: Microwave can penetrate clouds, and can distinguish the water content of ground objects, the growth of plants, the flooded area and so on.

(4)MSS image: the image provided by Landsat in the United States, with four scanning channels, geometric resolution of 79 * 79m, and imaging period of 18 days.

(5)TM image: There are 7 scanning channels with geometric resolution of 30 * 30m (infrared channel is 120 * 120m), and the period is still 18m.

(6)HRV image: provided by French satellite, there are four scanning channels, the geometric resolution of panchromatic channel is 10 * 20m, the other channels are 20 * 20m, and the period is 26 days.

(7) Meteorological satellite images: China-US meteorological satellite images.

(C) the main basis for image interpretation

(1) spectral characteristics; (2) physical characteristics; (3) Geometric features.

(d) Image correction and information extraction methods

(1) geometric correction; (2) radiation correction; (3) image enhancement; (4) Comparative analysis; (5) Statistical analysis; (6) Image classification.

(5) Practical examples

(1) topographic mapping; (2) Land use survey; (3) architectural investigation; (4) investigation of green vegetation; (5) environmental investigation; (6) Traffic investigation; (7) Landscape investigation; (8) Population estimation, that is, estimating the number and general distribution of the population by knowing the houses.

(vi) Limitations of remote sensing technology

(1) is a rough estimate of ground features or indirect information, which has errors.

(2) The error of computer interpretation is greater than that of manual interpretation.

(3) Social attributes are unavailable to computers.

(4) The cost is high, which requires the cooperation of various professionals.

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