Spatially connected edge strings are represented using the generic tina string structure (see programming guide). The start and end fields point to a pair of elements in a doubly directed list which in turn point to the individual edgels (one for each element in the list). Sub-strings chosen from complete edge strings can, if required, be constructed from the same list elements (they just have different start and end points).
The string to which an individual edgel belongs can be placed upon the the property list of the edgel using the key STRING. The list of strings for a particular edgerect (imrect of edges) is stored on its property list using STRINGS (or ER_STRINGS in old versions).