Concept of using external GIS files in the Application

The method of spatial selection internally within a MS-Access application and not externally with ArcView was first developed for the DVS (Digital Visualisation System).

It requires a GIS Plug-in (MapObjects Light 2 from ESRI). In order to require the desired functionality, a special data-model was built. This will particularly manage the following aspects:

Understanding this data model will enable the software developer to change the GIS layers in the individual applications as well as their appearance and functionality. This is not done by editing the programming code (VBA) but instead by the entries of data tables contained in the application.

There are 3 data tables required, their relation is shown in the screenshot below. (Click on the tables to go to the detailed descriptions).

Table TDataType lists the data types to be managed.
Key Fieldname Description of content
* DTCode Unique code of the data type. The first character has to be D for demands or R for resources. Each sub-module requires a separate code.
DTName Description of the data type as to be shown with the selection button

Table TShapeFiles lists the shape files to be used for spatial selection.
Key Fieldname Description of content
* SFCode Unique code for the shape file. Codes 01 - 20 indicate polygon shapes, 21 - 40 point shapes, 41 - 60 line shapes.
AVSFName Shape file name (without extension .shp)
AVSubDir Subdirectory where the shape file is located. The part of the path of the shape files which is common to all, is given by the configuration file preproc.cfg.
SFName Description of the shape file as to be shown with the selection button. It also is used for the generation of the Excel chart title.
CodeField Name of the field containing the code of the shape in the shape file's database table
NameField Name of the field containing the name of the shape in the shape file's database table. Code and name may be identical if only one of them exists.
SelOutputField Name of the field which will contain the code of the shape file in the output selection table. The contents has to be different to NameField as in most cases both fieldnames will be used for the generation of the selection table.
IntersectCode Intersection code
LabelThreshold Threshold when labels (names) should be displayed on the selection map
LabelSize Size of the labels
Color Color code for the polygons / points / lines


Table T_DT_SF lists the conjunction between data types DT and shape files SF

Key Fieldname Description of content
* DTCode Code of the data type
* SFCode Code of the shape file
SFjica Marking if the shape file can be used for selections based on the Excel files. J means it also may be used with the JICA Excel files.
allowSelect Indicates if the shape is selectable or only used for display.