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。
1.5.1. SVG Shapes ¶
SVG has some predefined shape elements that can be used and manipulated by developers:
Rectangle
Circle
Ellipse
Line
Broken line polyline>
Polygon
Path
The following sections will explain these elements, starting with rectangular elements.
1.5.2. SVG rectangle-
¶ Example 1 ¶
tags can be used to create rectangles, as well as variants of rectangles: Here is the SVG code:
Example
<svg xmlns="http://www.w3.org/2000/svg" version="1.1"> <rect width="300" height="100" style="fill:rgb(0,0,255);stroke-width:1;stroke:rgb(0,0,0)"/> svg>
For Opera users: view the SVG file (right-click the SVG drawing preview source).
Code parsing:
-
rectof the elementwidthandheightproperty defines the height and width of the rectangle -
styleProperty is used to define the CSS property -
CSS’s
fillproperty defines the fill color of the rectangle (rgb value, color name, or hexadecimal value) -
CSS’s
stroke-widthproperty defines the width of the rectangular border -
CSS’s
strokeproperty defines the color of the rectangular border
1.5.3. Example 2 ¶
Let’s look at another example, which contains some new properties:
Example
<svg xmlns="http://www.w3.org/2000/svg" version="1.1"> <rect x="50" y="20" width="150" height="150" style="fill:blue;stroke:pink;stroke-width:5;fill-opacity:0.1; stroke-opacity:0.9"/> svg>
For Opera users: view SVG files
Code parsing:
-
The x attribute defines the left position of the rectangle (for example, x = “0” defines that the distance from the rectangle to the left side of the browser window is 0px)
-
The y attribute defines the top position of the rectangle (for example, y = “0” defines that the distance from the rectangle to the top of the browserwindow is 0px)
-
CSS’s
fill-opacityproperty defines the fill color transparency (the legal range is: 0-1) -
CSS’s
stroke-opacityproperty defines the transparency of the outline color (the legal range is: 0-1)
1.5.4. Example 3 ¶
Define the opacity of the entire element:
Here is the SVG code:
Example
<svg xmlns="http://www.w3.org/2000/svg" version="1.1"> <rect x="50" y="20" width="150" height="150" style="fill:blue;stroke:pink;stroke-width:5;opacity:0.5"/> svg>
For Opera users: view SVG files
-
The CSS opacity attribute is used to define the transparency value of the element (range: 0 to 1).
1.5.5. Example 4 ¶
For the last example, create a rounded rectangle:
Here is the SVG code:
Example
<svg xmlns="http://www.w3.org/2000/svg" version="1.1"> <rect x="50" y="20" rx="20" ry="20" width="150" height="150" style="fill:red;stroke:black;stroke-width:5;opacity:0.5"/> svg>
For Opera users: view SVG files
-
rxandryproperty to fillet the rectangle.
- 1. Angularjs2 8
- 1. SVG tutorial 19
- 1.17. SVG gradient-Linear
- 1.20. SVG reference manual
- 1.14. SVG filter
- > 1.5. SVG <rect>
- 1.18. SVG gradient-radioactivity
- 1.2. SVG introduction
- 1.10. SVG <polyline>
- 1.16. SVG Shadow
- 1.19. SVG instance
- 1.8. SVG <line>
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- 1. Introduction to geographic information system 6
- 2. From the Real World to the Bit World 3
- 3. Spatial Data Model 7
- 4. 空间参照系统和 地图投影 5
- 5. Data in GIS 3
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- 9. 数字地形模型( DTM )与地形分析 5
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- 11. Spatial data representation and map making 6
- 12. 3S Integration Technology 5
- 13. 网络地理信息系统 3
- 14. Examples of Geographic Information System Application 8
- 15. Organization and Management of Geographic Information System Application Projects 9
- 16. Geographic Information system Software Engineering Technology 6
- 17. Geographic Information System Standards 3
- 18. Geographic Information System and Society 3
- 19. Earth Information Science and Digital Earth 3