最近几年来,地理信息系统无论是在理论上还是应用上都处在一个飞速发展的阶段。 GIS被应用于多个领域的建模和决策支持,如城市管理、区划、环境整治等等,地理信息成为信息时代重要的组成部分之一; “数字地球”概念的提出,更进一步推动了作为其技术支撑的GIS的发展。 与此同时,一些学者致力于相关的理论研究,如空间感知、空间数据误差、空间关系的形式化等等。 这恰好说明了地理信息系统作为应用技术和学科的两个方面,并且这两个方面构成了相互促进的发展过程。
Sass can help us reduce repetitive code in CSS and save development time.
We can install different properties to create some code files, such as variable definition files, color-related files, font-related files, and so on. Similar to CSS,Sass support CSS Sass the Note: there is no need to specify a file suffix when including a file. Sass will automatically add a suffix In addition, you can also import CSS files. After import, we can use variables such as import files in the main file. For the following example, import Next, let’s create a And then we’re here. Convert the above code to CSS code, as follows: If you don’t want to compile a Sass code file into a CSS file, you can add an underscore at the beginning of the file name. This will tell Sass not to compile it into a CSS file. However, we do not need to add an underscore in the import statement. Sass Partials syntax format: The following example creates a If you are importing the file, you do not need to use an underscore: Note: please do not put underlined and ununderlined files of the same name in the same directory, such as 13.5.1. Sass Import Fil ¶
@import instructions. @import directive allows us to import other files and so on. @import each time the instruction is called, an additional HTTP request is created. But, Sass, @import directive to include the file inthe CSS and no additional HTTP requests are required. @import instruction syntax is as follows:@import filename;
.scss . variables.scss 、 colors.scss and reset.scss files.Sass Code: ¶
@import "variables"; @import "colors"; @import "reset";
reset.scss file: reset.scss file code: ¶ html, body, ul, ol { margin: 0; padding: 0; }
standard.scss used in the file @import instruction import reset.scss file: standard.scss file code: ¶ @import "reset"; body { font-family: Helvetica, sans-serif; font-size: 18px; color: red; }
Css Code: ¶
html, body, ul, ol { margin: 0; padding: 0; } body { font-family: Helvetica, sans-serif; font-size: 18px; color: red; }
13.5.2. Sass Partials ¶
_filename;
\_colors.scss , but will not be compiledinto \_colors.css file: \_colors.scss file code: ¶ $myPink: #EE82EE; $myBlue: #4169E1; $myGreen: #8FBC8F;
Example ¶
@import "colors"; body { font-family: Helvetica, sans-serif; font-size: 18px; color: $myBlue; } _colors.scss and colors.scss cannotexist in the same directory at the same time, otherwise underlined files will be ignored.