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。
1.17.1. SVG gradient ¶
A gradient is a smooth transition from one color to another. In addition, multiple color transitions can be applied to the same element.
There are two main types of SVG gradients:
Linear
Radial
1.17.2. SVG linear gradient- ¶ element is used to define a linear gradient. labels must be nested in the on the inside. the label is definitions , that defines special elements such as gradients A linear gradient can be defined as a horizontal, vertical, or angular gradient:
When y1 and y2 are equal, but x1 and x2 are different, a horizontal gradientcan be created.
When x1 and x2 are equal, but y1 and y2 are different, a vertical gradient can be created.
When x1 and x2 are different, and y1 and y2 are different, an angular gradient can be created.
1.17.3. Example 1 ¶
Define the oval shape of the horizontal linear gradient from yellow to red:
Here is the SVG code:Example ¶
<svgxmlns="http://www.w3.org/2000/svg"version="1.1"><defs><linearGradientid="grad1"x1="0%"y1="0%"x2="100%"y2="0%"><stopoffset="0%"style="stop-color:rgb(255,255,0);stop-opacity:1"/><stopoffset="100%"style="stop-color:rgb(255,0,0);stop-opacity:1"/>linearGradient>defs><ellipsecx="200"cy="70"rx="85"ry="55"fill="url(#grad1)"/>svg> Code parsing:
-
id attribute of the tag defines a unique name for the gradient -
the X1 ~ X2 ~ X2 ~ Y1 ~ Y2 attribute of the tag definesthe start and end of the gradient. -
The color range of a gradient can be made up of two or more colors. Each color passes through a Label to specify. offset property isused to define the start and end positions of the gradient. -
Populate the attribute to ellipse elements are linked to this gradient
1.17.4. Example 2 ¶
Define an oval with a vertical linear gradient from yellow to red:
Here is the SVG code:
Example ¶
<svgxmlns="http://www.w3.org/2000/svg"version="1.1"><defs><linearGradientid="grad1"x1="0%"y1="0%"x2="0%"y2="100%"><stopoffset="0%"style="stop-color:rgb(255,255,0);stop-opacity:1"/><stopoffset="100%"style="stop-color:rgb(255,0,0);stop-opacity:1"/>linearGradient>defs><ellipsecx="200"cy="70"rx="85"ry="55"fill="url(#grad1)"/>svg> 1.17.5. Example 3 ¶
Define an oval, horizontal linear gradient from yellow to red and add text within the ellipse:
Here is the SVG code:
Example ¶
<svgxmlns="http://www.w3.org/2000/svg"version="1.1"><defs><linearGradientid="grad1"x1="0%"y1="0%"x2="100%"y2="0%"><stopoffset="0%"style="stop-color:rgb(255,255,0);stop-opacity:1"/><stopoffset="100%"style="stop-color:rgb(255,0,0);stop-opacity:1"/>linearGradient>defs><ellipsecx="200"cy="70"rx="85"ry="55"fill="url(#grad1)"/><textfill="#ffffff"font-size="45"font-family="Verdana"x="150"y="86">SVGtext>svg> Code parsing:
-
element is used to add a text
-
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>
-
1. Memcached
20
-
1. C# tutorial
61
-
1. Sqlite
47
-
2. Go
43
-
2. Docker
59
-
2. Vue3
19
-
2. Servlet
21
-
3. React
23
-
3. SOAP tutorial
10
-
3. Android
18
-
3. Mongodb
44
-
3. Kotlin
18
-
4. Lua
31
-
4. MySQL tutorial
35
-
4. Appml
12
-
5. Perl
45
-
5. Postgresql
41
-
web
15
-
5. Web Services tutorial
6
-
6. Ruby
42
-
6. Design-pattern
35
-
7. Django
18
-
7. Rust
22
-
6. WSDL tutorial
8
-
8. Foundation
39
-
9. Ios
43
-
8. Css3
26
-
9. Swift
44
-
11. HTML tutorial-(HTML5 Standard)
54
-
12. Http
6
-
13. Regex
6
-
14. Regexp
8
-
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
-
6. Spatial data acquisition
2
-
7. Spatial Data Management
6
-
8. Spatial analysis
8
-
9. 数字地形模型（ DTM ）与地形分析
5
-
10. 空间建模与 空间决策支持
6
-
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
A linear gradient can be defined as a horizontal, vertical, or angular gradient: When y1 and y2 are equal, but x1 and x2 are different, a horizontal gradientcan be created. When x1 and x2 are equal, but y1 and y2 are different, a vertical gradient can be created. When x1 and x2 are different, and y1 and y2 are different, an angular gradient can be created. Define the oval shape of the horizontal linear gradient from yellow to red: Here is the SVG code: Code parsing: The color range of a gradient can be made up of two or more colors. Each color passes through a Populate the attribute to Define an oval with a vertical linear gradient from yellow to red: Here is the SVG code: Define an oval, horizontal linear gradient from yellow to red and add text within the ellipse: Here is the SVG code: Code parsing: definitions , that defines special elements such as gradients 1.17.3. Example 1 ¶
Example ¶
<svgxmlns="http://www.w3.org/2000/svg"version="1.1"><defs><linearGradientid="grad1"x1="0%"y1="0%"x2="100%"y2="0%"><stopoffset="0%"style="stop-color:rgb(255,255,0);stop-opacity:1"/><stopoffset="100%"style="stop-color:rgb(255,0,0);stop-opacity:1"/>linearGradient>defs><ellipsecx="200"cy="70"rx="85"ry="55"fill="url(#grad1)"/>svg>
offset property isused to define the start and end positions of the gradient. ellipse elements are linked to this gradient 1.17.4. Example 2 ¶
Example ¶
<svgxmlns="http://www.w3.org/2000/svg"version="1.1"><defs><linearGradientid="grad1"x1="0%"y1="0%"x2="0%"y2="100%"><stopoffset="0%"style="stop-color:rgb(255,255,0);stop-opacity:1"/><stopoffset="100%"style="stop-color:rgb(255,0,0);stop-opacity:1"/>linearGradient>defs><ellipsecx="200"cy="70"rx="85"ry="55"fill="url(#grad1)"/>svg>
1.17.5. Example 3 ¶
Example ¶
<svgxmlns="http://www.w3.org/2000/svg"version="1.1"><defs><linearGradientid="grad1"x1="0%"y1="0%"x2="100%"y2="0%"><stopoffset="0%"style="stop-color:rgb(255,255,0);stop-opacity:1"/><stopoffset="100%"style="stop-color:rgb(255,0,0);stop-opacity:1"/>linearGradient>defs><ellipsecx="200"cy="70"rx="85"ry="55"fill="url(#grad1)"/><textfill="#ffffff"font-size="45"font-family="Verdana"x="150"y="86">SVGtext>svg>