Type
Technical Study

Remote Sensing is defined as the science and technology by which characteristics of objects and areas of interest can be identified and obtained without direct contact, typically from aircrafts or satellites. Advantages of remote sensing over on-site observation include: Ability to observe a broad area at a time. Repeat pass observation / time-series studies (Change detection). Ability to identify and study the condition without visiting the area.

Obtaining “invisible” information: Sensors for various electromagnetic spectrum (infrared, microwave). Remote sensing data is typically stored in raster images with varying spatial, spectral, and temporal resolutions. Raster images are composed of a matrix of picture elements, or pixels, which are the smallest units of an image. In GIS, raster image pixels are referred to as cells. Cells are normally square and may correspond to areas ranging in side length from less than 1 to more than 1,000 meters (3.3 to 3,280.8 ft).

One of the most important applications of remote sensing has been tracing the transformation of land patterns and urbanization over time. The availability of free Landsat satellite images that have been in orbit since 1972 has made it possible for us to map land cover at different spatial and temporal scales and to create quantitative analysis of land cover changes between then and now and whatever time increment is chosen. It is up to designer, however, to interpret the ground condition, and to speculate and recognize how the changes of certain features on the ground lend themselves to a story of the process of urbanization and lead to a variety of interpretations and design responses. In this exercise, we will learn land cover classification methods using Landsat satellite imagery, and then drill deeper into evaluating the change quantitatively.

Four major hurricanes – Harvey, Irma, Jose, and Maria – have ravaged the US in 2017. Since hurricane forecasting has vastly improved in the past century, many lives have been saved. However, despite the accurate forecasting, the damages incurred during the last year’s season have been among the most costly in recorded history. Advances in forecasting have not stopped us from continuing to build in the floodplain.

In the case of Houston, TX, the loss of wetlands as a result of lax regulations and rampant development has been a major cause of flooding that ultimately resulted in catastrophic property damage. There is a scientific consensus that wetlands can absorb large amounts of flood water. While it is fair to say that the vanished wetlands of Houston wouldn’t have prevented flooding, experts agree that they would have made it a lot less painful.