书名：Mastering Geospatial Development with QGIS 3.x
作者名：Shammunul Islam Simon Miles GISP Menke GISP Smith Jr. Luigi Pirelli GISP Van Hoesen
本章字数：405字
更新时间：2025-04-04 14:40:31

Singleband pseudocolor interpolations

The following interpolations fall under the singleband pseudocolor option. Let's have a quick look at them:

Linear: By default, QGIS displays the raster under the singleband pseudocolor option with an Interpolation set to Linear. It assigns a unique color to each unique raster value. Values between values that are listed in the Value column are assigned a unique color that is calculated linearly and is based on its location between the surrounding listed values. In other words, if there are, say, 164 unique values in the raster and 15 colors listed in the classification list, the raster will be rendered with the 164 unique colors that appear as a nice, linear progression through the 15 listed colors. This method is best for raster data that represents continuous information (for example, elevation or temperature data) where you want a smooth progression of color that stretches across the raster values. If you change this value to Discrete, then click on Classify and then Apply; the rendering of the raster will change.
Discrete: Assigns only, and exactly, the colors that were chosen in the classification list. Values between values that are listed in the Value column are assigned the color that are assigned to the next highest listed value. In other words, if there are, say, 164 unique values in the raster and 15 colors listed in the classification list, the raster will be rendered with exactly the 15 listed colors. This method is best for cases where you want to reduce the number of colors that will be used to render the raster. Furthermore, you can change the value to Exact, then click on Classify, and then Apply.
Exact: This assigns a unique color to only the values listed in the Value column of the classification list. In other words, if there are, say, 164 unique values in the raster and 15 colors (and 15 associated values) listed in the classification list, only the 15 raster values that are listed will be rendered with their associated colors. No other values will be assigned a color. This method is best for raster data that represents discrete data classes where you do not want non-listed values to be assigned any color.

The following screenshot shows the effects of the three Color interpolation methods on our sample data, as configured so far: