for node-field highlights are stored in the node-field locations table.

A layout object is created in the main script and passed to the layout production script for population and formatting. First, the page properties are established. This revealed what appeared to be a bug. The units of measure for the layout could not be reset from the default inches.

The title and patient details are placed at the top of the page using the auxiliary DrawText script. The borders are placed on the layout using the auxiliary DrawBox script. Finally, the view is placed within the border and sized so that it is at the largest scale possible.

Auxiliary Scripts, Tables and Images

Two auxiliary scripts were developed. The first, Drawtext, instructs the program to place, or pass, a graphics object, a location and the text that is to be placed on the graphics layer. Optionally, it can be passed point size, text angle, font name and font style. If the optional arguments are not passed, defaults are used. The second script, DrawBox, is passed a graphics object and a rectangle object with the location and dimensions of the box.

Wherever possible, tables are used to store information for the application. Avenue's table handling capabilities are limited, but as the tables are not large, performance is not a major concern. The principal table is the node-field locations table, which stores the location and dimension of the highlight box to be drawn for any given node field on any given map.

There are six images stored as part of the application. These are the schematic diagrams for the posterior and anterior torso, posterior and anterior lower limbs and left and right lateral head. When the report is produced, the appropriate image is placed on the view as a theme.

Complementary Apps

Inter-Application Communication (IAC) relies on the ability of ArcView to accept information from another application either through DDE (on the Windows platform) or AppleTalk. This is an excellent example of the use of complementary applications running under an operating system and shows how data can be shared between tools allowing developers to choose the appropriate tools for the job, rather than simply the monolithic application that meets most of the criteria.

In addition to IAC, the other feature of ArcView, Filemaker Pro and Excel (and several other applications), which makes development easier, is the ability to develop on one platform (in this case Windows) and to implement the solution on another (in this case the Macintosh). The ArcView code needs no modification and the Excel code only requires small changes to make the IAC calls appropriate to the operating system.

Geocoding Melanoma Data

Over 1400 patients have undergone lymphoscintigraphy in this study. In each case, the draining node fields and the number and location of the sentinel nodes and any interval nodes were recorded in a Filemaker Pro database file. The challenge inherent in using a GIS to map the data was that the locations were descriptive. Only a small sketch of the location had been recorded, and the images produced by the lymphoscintigraphy did not have any common reference points marked to allow normalization and automatic geocoding of locations.

Six schematic diagrams representing the surface of the body were drawn and a grid marked on them. Each case was manually reviewed and a map number, and x and y coordinates were recorded for each primary lesion site. These coordinates were then randomized within the level of precision of the grid used to avoid clustering at grid points.

The schematic diagrams of the body were scanned as TIFF files. These images were geocoded using the ARC/INFO commands REGISTER and RECTIFY. The maximum RMS error in the registration process was 0.38mm, less than 10 percent of