【20090702-01】Diff between Raster Dataset and Raster Catalog (转)
|
Raster dataset 栅格数据集 |
Raster catalog 栅格目录 |
数据源 |
A single picture of an object or a seamless image covering a spatially continuous area. This may be a single original image or the result of many images appended (mosaicked) together. 在空间上连续的单张图片 多张同种格式的图片进行合并得到的 |
A collection of raster datasets displayed as a single layer. They can be in different coordinate systems and can have different data types. 显示在同一个图层上的多个栅格数据集的集合 组成这个集合的栅格数据可以有不同的坐标系统和数据格式类型 |
图层 |
One map layer. 在同一个图层 |
One map layer. 在同一个图层 |
数据源的差异 |
Homogeneous data: a single format, data type, and file. 必须由单一的影像格式、数据类型和文件构成 |
Heterogeneous data: multiple formats, data types, file sizes, and coordinate systems. 支持多个影像格式、数据类型、文件大小和坐标系统 |
数据存储方式 |
Stored once and applies to complete dataset. 一次性存储,并应用于完整的数据集 |
Stored as attribute columns for each raster dataset item in the raster catalog. 每个栅格数据集项都作为一个属性列存储在栅格目录中 |
金字塔 |
A single pyramid on the entire raster dataset. 整个栅格数据集上构建单个金字塔 |
A pyramid for each raster dataset in the raster catalog. 栅格目录中的每个数据集都建立一个金字塔 |
优点 |
Fast to display at any scale. Mosaic saves space, since there is no overlapping data. Displays with better blending at mosaicked image seams. 在每个比例尺下显示都很快。镶嵌因为没有冗余数据而节省了空间,通过无缝拼接得到的影像数据集在显示上更有优势 |
Can manage multirow raster tables for many purposes. Can specify one or more raster datasets for display. 可以管理多行栅格数据表,也可以显示指定的一个或多个栅格数据集 |
缺点 |
File and personal geodatabase raster datasets are slower to update because the entire file has to be rewritten. 文件地理数据库和个人地理数据库中的栅格数据更新是比较慢的,整个文件在更新时都必须重写 |
File-based raster catalogs with different data types may not render well. Displaying many raster dataset items from a raster catalog can be time consuming. 基于文件的并由不同数据格式组成的栅格目录渲染效果不是很好。在栅格目录中显示大型的栅格数据会有时间上的延迟
|
建议 |
Use raster datasets when overlaps between mosaicked images do not need to be retained and for fast display of large quantities of raster data. 使用栅格数据集去掉了图片之间相重叠的部分,因而对于高质量的栅格数据来说具有更快的显示效果
|
Use a raster catalog for massive image repositories, retaining overlaps between datasets, managing time series data, and when differences among adjoining images prevent mosaicking. 需要保留了数据集之间相重叠的部分,管理时间系列数据,以及当禁止镶嵌的邻接图像之间可以存在差异时,可以使用栅格目录用来建立巨型的栅格仓库 |