Esri specialist 在社区中对ArcGIS9.2 xy domain设定进行修改的原因的经典描述
2007-05-18 16:37
302 查看
If you set the coordinate system when creating a new feature class or dataset, we use the coordinate system's (map projection) valid extent. This is larger than the coordinate system's valid area of use. For example, in your case, the extent of North Carolina is the valid area of use. The 'valid extent' is what's supported mathematically by the Lambert conformal conic projection which covers a much larger area.
For geographic coordinate systems, the valid extent is greater than the world.
We usually set the minimum extent/domain and resolution values. That often means that the maximum values are much larger than required. This could happen prior to 9.2 too, but wasn't as obvious.
There are several reasons we do this. One is that we have the information available about the valid extent available now. Two, with "high precision" aka 64bit/53bit, we can support the valid extent and also maintain reasonable resolution values. If you use the actual area of use of your data in a high precision gdb, the resolution value will be ridiculously small, which can cause performance problems.
You may have seen the 2147483647 value before in connection with the pre-9.2 geodatabase? Values, after an internal conversion using the domain and precision (1/resolution), had to fit between 0 and 2147483647. At 9.2, we now use 2^53-2 or 9007199254740990 for the max permitted value. We have a lot more space to work with.
There's going to be a white paper on this, in a month or so.
So, the things to remember at 9.2 when setting up a feature class/dataset are:
1. set the coordinate system
2. The tolerance values should reflect the accuracy of your data.
2. The resolution values should be at least 10 times smaller than the corresponding tolerance values. The resolution values dictate the minimum distance between two points in the feature class.
For geographic coordinate systems, the valid extent is greater than the world.
We usually set the minimum extent/domain and resolution values. That often means that the maximum values are much larger than required. This could happen prior to 9.2 too, but wasn't as obvious.
There are several reasons we do this. One is that we have the information available about the valid extent available now. Two, with "high precision" aka 64bit/53bit, we can support the valid extent and also maintain reasonable resolution values. If you use the actual area of use of your data in a high precision gdb, the resolution value will be ridiculously small, which can cause performance problems.
You may have seen the 2147483647 value before in connection with the pre-9.2 geodatabase? Values, after an internal conversion using the domain and precision (1/resolution), had to fit between 0 and 2147483647. At 9.2, we now use 2^53-2 or 9007199254740990 for the max permitted value. We have a lot more space to work with.
There's going to be a white paper on this, in a month or so.
So, the things to remember at 9.2 when setting up a feature class/dataset are:
1. set the coordinate system
2. The tolerance values should reflect the accuracy of your data.
2. The resolution values should be at least 10 times smaller than the corresponding tolerance values. The resolution values dictate the minimum distance between two points in the feature class.
相关文章推荐
- ArcGIS 9.1和9.2中xy domain的区别
- ArcGIS API for Javascript 使用query查询以某个点为半径的圆内的要素出现“esri.config.defaults.io.proxyUrl 尚未进行设置”错误
- ESRI系列产品报价表(ArcGIS 9.2系列)
- 上一篇,在Websphere上使用Axis做的客户端调用Webservice要进行修改配置的原因
- 集合迭代时对集合进行修改抛ConcurrentModificationException原因的深究以及解决方案
- ArcGIS for Desktop入门教程_第七章_使用ArcGIS进行空间分析 - ArcGIS知乎-新一代ArcGIS问答社区
- 在ArcGIS9.3中修改ESRI自带脚本库
- ArcGIS API for Javascript 使用缓冲区结果做query查询出现“esri.config.defaults.io.proxyUrl 尚未进行设置”错误
- ArcGIS9.2进行投影
- 解决ArcGIS9.2以前程序引用ESRI.ArcGIS.Utility在ArcGIS10找不到问题
- ESRI 发布 ArcGIS 9.2 sp3
- 解决ArcGIS9.2以前程序引用ESRI.ArcGIS.Utility在ArcGIS10找不到问题
- System.Windows.Forms.AxHost.InvalidActiveXStateException”类型的异常在 ESRI.ArcGIS.AxControls.dll 中发生,但未在用户代码中进行处理
- ArcGIS API for Javascript 使用缓冲区结果做query查询出现“esri.config.defaults.io.proxyUrl 尚未进行设置”错误
- ArcGIS.Server.9.2.DotNet 查询地图元素进行定位显示
- learn-with-open-source 如何进行开源社区的学习系列经典文章
- 集合迭代时对集合进行修改抛ConcurrentModificationException原因的深究以及解决方案
- Esri中国社区 » GIS大讲堂:ArcGIS Server .Net ADF中的AJAX
- 集合迭代时对集合进行修改抛ConcurrentModificationException 原因 以及解决方案
- 【2013Esri开发者大会精彩看点】ArcGIS平台及其特性描述