Introduction

Details

Last Updated on Friday, 11 January 2013 15:23

GeoDMS

The Geo Data and Model Server (GeoDMS) consists of three components:

• Engine component to control and calculate data, models, modelruns, model results and scenarios. The engine component consists of a set of dll's written in C++.
• GUI component to view and edit (meta)data and model configurations. The GUI component is an executable called GeoDmsGui.exe, written in Delphi.
• An executable used to update tree items from a command line or batch file. This component is called GeoDmsRun.exe, written in C++.

The GeoDMS software is developed for research and modeling environments. It is useful for multiple decision, discussion and policy support systems. The main focus of the projects in which the GeoDMS is used are on spatial decision and planning support. The GeoDMS therefore contains much functionality to calculate and view spatial (related) data. But also in other policy areas the GeoDMS can be very useful.The GeoDMS is the result of many years experience in the development of decision support systems and the resulting knowledge on shortcomings of alternative components/frameworks.

Focus

The main focus of the GeoDMS is on a controlled and efficient calculation process. Besides the powerfull set of functions & operators, much attention has been given to:

• the description of data and it's sources;
• an efficient mechanism to determine how and when results need to be calculated;
• the control of the status of (in between) results;
• the management of units to keep modeling steps consistent and prevent modeling errors;
• breaking up the 'black box' concepts of models by configuration calculations in clear, atomic calculation steps, using meta information and a clear visualisation of the calculation logic;
• the visualisation of spatial (related) data in different map layer types;
• the visualisation of attribute data in tables;

The reasoning behind developing the GeoDMS is: Results sec are not enough. It is just as important to present how results are derived by informing a user:

• which input data is used;
• which assumptions are made in the model;
• which calculation steps are performed.

Repeatability

An important condition for this reasoning is the repeatability of calculations. Within the GeoDMS identical calculations can be executed when input parameters are changed and results are requested. The GeoDMS controls which (in between) results are still valid and which results need to be recalculated, guaranteeing:

• the user always valid results also if changes have occurred in the source data/parameters;
• calculations are peformed efficiently.

To execute calculations in the GeoDMS, expressions are configured to data items. In expressions functions & operators are used to configure the actual calculation steps. A scala of basic functions & operators can be used within the GeoDMS. These functions & operators can be applied for mathematical, statistical, relational, geographic, grid and textual operations.

Except from the calculations configured in expressions, the GeoDMS also offers the possibility to execute external components (model or calculation components implemented in another modeling or programming environment). This can be useful if much time has been spent on the implementation of an external component or if operations can only be performed in another environment. The disadvantage of external components is that these components will remain a black box in which e.g. units can not be controlled. Much of the strength of the GeoDMS is lost if relevant parts of the analyses are implemented in external components.