CalcCache Purpose - ObjectVision/GeoDMS GitHub Wiki

CalcCache Purpose

The [GeoDMS](GeoDMS GUI) CalcCache is in use for two purposes:

performance

Although the GeoDMS is designed to calculate fast with large datasets (see Expression, Fast Calculations), calculating some results, for instance a 100-meter grid allocation for large countries in Europe, can take some time.

The CalcCache can store (part of) these results on disk. This allows the GeoDMS to re-use these results after being calculated once, provided they are still valid (no input data or expression of any supplier is changed). The results can be made available in the session with which the results are calculated, but also after restarting the application in a new session.

calculating with large datasets

The limit of around 1 gigabyte internal memory that can be addressed by any process in a 32 bits Windows environment became a problem in for instance the allocation model of the Netherlands at a 100-meter grid level. The total amount of data needed to calculate all steps in this model exceeds this limit of 1 gigabyte. The solution is to store interim results of the calculation process on disk.

The CalcCache provides the [[GeoDMS|GeoDMS GUI] the opportunity to calculate models with large datasets also in a 32 bits environment, where the total amount of data used exceeds the 1 gigabyte internal memory limit.

In a 64 bits environment, this limit of 1 gigabyte is not an issue, but still the physical amount of the internal memory is limited. So also in 64 bits environments the CalcCache is useful for this purpose.