Geodeziya, kartografiya, geografiya

LAND COVER CLASSIFICATION METHODS

This document provides an overview of land cover classification using remotely sensed data. We will describe different options for conducting land cover classification will be described including types of imagery, methods and algorithms, and classification schemes. Using this guide, you will learn how to carry out a land cover classification project, while gaining an appreciation for the image classification process. Land cover mapping is not as difficult as it may appear, but there are many decisions, choices, and compromises regarding image selection and analysis methods that must be made. Although it is beyond the scope of this guide to provide details for all situations, you will at least be able to assess your own needs and requirements. If you lack experience with land cover mapping we suggest that you work with someone with sufficient experience.

What is the difference between land cover and land use?
Although the terms "land cover" and "land use" are sometimes used interchangeably, they are actually different. Simply put, land cover is what covers the surface of the earth and land use describes how the land is used. Examples of land cover classes include: water, snow, grassland, deciduous forest, and bare soil. Land use examples include: wildlife management area, agricultural land, urban, and recreation area. Some classified maps include a mix of land cover and land use. Although there is nothing inherently wrong with this approach, it can sometimes lead to confusion. It is important that each class on the map be clearly defined and distinct from other classes.
Some maps include both land cover and land use information. One way to do this is to represent land cover using different colors, while using different patterns or symbols overlaid on the map to represent land use.
Where do I start?
A good place to start is to determine if you really need a classified map. You might want to read the guide titled: Justification for using photo interpretation methods to interpret satellite imagery to see if your needs can be met simply using image photo products instead of a classified map. Should you decide that a land cover map is necessary, you will need to have a good understanding of why the map is being created and how it will be used. Reading this document should provide sufficient information regarding factors to consider for a needs assessment. You should write down the the results of this needs assessment. It will become obvious that there are several decisions that you need to make based upon what the map will be used for. Accordingly, these decisions will determine many of your choices throughout the classification process. The next several sections detail the steps you will take during a land cover mapping project.