Local vs Global Bases Assignment help
- Global Base import always means that already imported base files (Speaker Models and Wall Materials) won't be re imported. New base files will be added to this list (Import21.lsp and Import21.wal), so that every base file is only imported once. This means they are somehow public to other imported projects and they will be used in future imports according to that list. Base files shipping with Ease 3.0 on the CD are registered as already imported during the installation. So in most cases they will be used.
- Local Base import never considers any already existing Speaker Models or Wall Materials. Additionally all base files are reimported in a more private subdirectory of the project. They are not added to the list (Import21.lsp and Import21.wal), as a result they won't be available as already imported base files for other import procedures. The only way to use them in other projects is to set the pointers manually with Select Speaker Models or Select Wall Materials in the Project Data Module.
- Import Project Group/Local Base is a mixture of both. The import book files Import21.lsp and Import21.wal are not used, but projects are allowed to use the same imported base files, if they are imported in one step. The structure created is very similiar to the old Ease 2.1 style.
A scene allows you to visualize 2D and 3D data and analyze geographic information in an intuitive and interactive 3D environment. You can choose between a global or local scene to best display your data, such as airline flight patterns, campus facilities, or underground utilities. You can view scenes in either the scene viewer or in ArcGIS Pro.
A global scene is where you can display your 2D and 3D content on a sphere based on Web Mercator (Auxiliary Sphere)or GCS WGS 84 world coordinate systems. A global scene is good to use when you want to understand or provide context for phenomena that wrap around the spherical surface of the earth, such as global weather measurements, world population, or shipping lanes. You can also use a global scene to display your 3D data at a city level or even down to a building site level.
In most cases <<- will assign to variables already in the global environment or create a variable in the global environment even if you're inside a function. However, it isn't quite as straightforward as that. What it does is checks the parent environment for a variable with the name of interest. If it doesn't find it in your parent environment it goes to the parent of the parent environment (at the time the function was created) and looks there. It continues upward to the global environment and if it isn't found in the global environment it will assign the variable in the global environment.
Local objects are stored in a frame in virtual memory (e.g. RAM). Frame 0 is called the session frame or “global environment” and exists as long as R is operational. Frame 1 and higher are created to support function execution only. Each of these frames contain a list of R objects with names and values. Objects stored in Frame 1 and higher are erased when flow control returns to the Console. The temporary use of virtual memory implies that functions offer an efficiency advantage over scripts as functions make little to no use of disk or virtual storage.
Global Objects and the Data Directory
Data objects that are global are stored in the .Data directory. As a result, they persist until they are explicitly removed (or the search path is altered). Scripts the contain no functions and expressions defined in the Console create global objects, they rely on hard disk storage, and they are fundamentally slower to process. Local objects within functions become permanent or global objects only through the use of the assign() function or the infix operator <<-. Explicit assignment transfers an object from RAM or virtual memory to the hard-drive.