地理信息系统导论课后习题英文版7.docx

Chapter 7 Review Questions
1. Explain map-to-map transformation.
Map-to-map transformation is one type of geometric transformation that converts the newly digitized map into projected coordinates.
2. Explain image-to-map transformation.
Image-to-map transformation is one type of geometric transformation that converts the rows and columns (i.e., the image coordinates) of a satellite image into projected coordinates.
An image-to-map transformation is sometimes called an image-to-world transformation. Why?
An image-to-map transformation is also called an image-to-world transformation because the process converts a satellite image into real-world coordinates.
The affine transformation allows rotation, translation, skew, and differential scaling. Describe each of these transformations.
Rotation can rotate a map’xs- and y-axis from the origin. Translation can shift its origin to a new location. Skew can allow a nonperpendicularity (or affinity) between the axes, thus changing its shape to a parallelogram with a slanted direction. And differential scaling can change the scale by expanding or reducing in thex and/or y direction.
Operationally, an affine transformation involves three sequential steps. What are these steps?
Step 1: update thex- and y-coordinates of selected control points to real-world coordinates.
Step 2: run an affine transf