Infill

In urban planning, infill is the use of land within a built-up area for further construction.

Source: tatoeba (2666501)

Here the original drawing is shown in grey and the infilled tracing in black. The lettering can be further refined and, unlike ink-based artwork, can be rekerned without being redrawn.

Source: wiktionary

Government needs to provide certainty to the rail freight industry with infill electrification programmes [...]. "First, it's about Government committing to infill electrification so we can do things with the locomotives we already have, and then a rolling plan of electrification."

Source: wiktionary

Hinton and I were briefed at the TOC and received maps of our AO to memorize and mark with codes for the primary and secondary LZs for infill and exfill.

Source: wiktionary