Keeping subdocuments in separate image files and having them logically connected in a single TCD document is a recommended way of working and should be used whenever possible. Sometimes however, a need may arise to merge selected subdocuments into a single raster file, e.g. in order to make the combined images available to applications that do not support composite documents.

Open townmap.tcd and select two subdocuments, as described in the previous section on Selecting and controlling subdocuments . Click the Merge rasters button on the Raster toolbar and type a new file name, e.g. maps1&4.tif , for the merged file in the Merge selected images to dialog box that pops up on the screen. After having the merge operation completed, open the newly created file. It should contain the selected subdocuments merged into one file, as shown below.

The Merge rasters command is particularly useful when merging a larger number of subdocuments selected from a complex TCD file with dozens or even hundreds of subdocument links. Each subdocument preserves its position in the world coordinates system, so, if the source subdocuments were calibrated, the merged result will be equally well calibrated without any additional actions.