彩票走势图

数据格式

　　地图服务器支持多种数据，包括光栅图片以及矢量格式。不管图片的分辨率大小，矢量数据都非常简约并精确。它非常适合用于呈现城镇、街道、人口分布区域以及国家边界等元素。

　　矢量数据的例子包括美国人口普查数据，它提供了整个美国的细致到街道的详细信息。另外一个例子是NIMA的世界数字图（VMap0/VPF），它提供了整个世界的国家、海岸线、国界、人口分布、交通、工业、植被以及其它的数据。这两组数据都能在GLG地图服务器中使用。

　　光栅图片数据能通过提供生动华美的信息极大地改善地图图片的外观及精密程度以充实覆盖在图片之上的附加矢量数据（道路数据等）。NASA Earth Image dataset是典型的光栅图片数据的例子，它频繁地被使用在多种地球图片中。地图服务器提供多个特殊的半透明与透明模式以覆盖在其它光栅与矢量层上的半透明天气地图。

　　海拔数据是光栅图片数据中一种特殊的情况，它能以彩色的阈值或投影图片显示海拔。它同样能用来在地图的特定点请求海拔。

网页服务器或独立的库API运用模式

　　GLG地图服务器能以基于网页的GIS地图服务器或独立的库API的模式运行。在独立模式下，地图服务器能以连接到程序的C/C++库的模式工作：该模式可用于那些希望避免使用互联网连接来接收地图图片的并安装在本地机器上的应用程序。当以库的模式连接到应用程序时，地图服务器不需要任何连接到外部的连接，它为实时、内置的应用程序提供了一个小而且是自足的地图生成模板。 

Data Formats

　　The map server supports a variety of data in both raster image and vector formats. The vector data appear crisp and precise regardless of the resolution of the image and is ideal for representing such elements as cities and towns, roads and streets, populated areas and country boundaries.

　　Examples of vector data include US Census/Tiger data, which provides street-level detail for the entire continental United States, as well as NIMA's Digital Chart of the World (VMap0 / VPF) that provides country, shoreline, political boundary, population, transportation and industry, vegetation and other data for the entire world. Both datasets are available for use with the GLG Map Server.

　　The raster image data can greatly enhance the look and sophistication of a map image by providing vivid and colorful details to compliment the additional vector data (roads, etc.) overlaid on top of the image. One example of raster image data is a NASA Earth Image dataset, which is frequently used in various Earth images. The map server provides several special alpha-blending and transparency modes for overlaying semi-transparent weather maps on top of other raster and vector layers.

　　Elevation data is a special case of the raster image data which can be used to display elevation as color-coded thresholds or shaded relief image. It may also be used to query elevation of a particular point on the map.

Web-Server or Stand-Alone Library API Usage Mode

　　The GLG Map Server can operate both as a web-based GIS Map Server or stand-alone library API. In the stand-alone mode, the map server can be used as a C/C++ library  linked with a program: this mode may be used for applications installed on local machines that want to avoid using an Internet connection to receive map images. When linked with an application as a library, the map server does not require any connections to the outside world, providing a small and self-contained map generation module for real-time and embedded applications.