1. Natural surface objects have their own laws of electromagnetic radiation, and different ground objects have different abilities of reflecting, emitting and absorbing different electromagnetic waves, which is called spectral characteristics of ground objects.
Using natural electromagnetic waves, or artificially emitted electromagnetic waves, or using the electromagnetic waves of ground objects themselves, we can record the spectrum and its geometric position, interpret (explain) the distribution law of surface objects, and realize long-distance and non-contact observation of the surface, which is called remote sensing.
2. In urban planning and related fields, the electromagnetic radiation sources of remote sensing are mainly the visible light and infrared rays of the sun, and sometimes the infrared rays of microwave radar or ground objects themselves are also used.
An instrument for detecting and recording electromagnetic waves is called a sensor, which can be installed on an airplane (or balloon) and is called aerial remote sensing. It can also be installed on an artificial earth satellite, which is called space remote sensing.
Aerial remote sensing has great flexibility, strong pertinence and high geometric resolution of information.
3. The information obtained by sensors is generally image information, also called remote sensing image. There are two main ways to obtain images: photography or scanning.
4. Spectral range and resolution, image coverage and geometric resolution, and phase are the main technical indicators of remote sensing images.
Spectral range is the maximum range of received and recorded electromagnetic wave wavelengths, and spectral resolution refers to the minimum wavelength range that can be resolved on the image map. Image coverage is the spatial range of the surface covered by the image, and the geometric resolution of the image refers to the smallest feature size that can be distinguished on the image map.
For more information about project/service/procurement bidding, and to improve the winning rate, please click on the bottom of official website Customer Service for free consultation:/#/? source=bdzd