It is common practice to distinguish delimitation and demarcation of a boundary.

Delimitation:
"Description of the alignment in a treaty or other written source, or by means of a line marked on a map or chart."

Demarcation:
"The means by which the described alignment is marked, or evidenced, on the ground by means of cairns of stones, concrete pillars, beacons of various kinds, cleared roads, and so on."

"The principle of distinction is clear enough, but the usage of the draftsman of a particular international agreement or political spokesman may not be consistent. In fact the terms are sometimes used to mean the same thing. "

"The distinction is logical and reflects the general experience. However, in certain circumstances the relations between delimitation and demarcation are significantly different. In the first place a not uncommon procedure is for governments to define their common boundary in principle and at the same time agree to establish a joint commission which will establish a more precise alignment by means of a detailed survey and demarcation. The work of the joint commision will then be embodied in an international agreement to which will be annexed an elaborate boundary description, usually in the form of a lengthy schedule of boundary pillars and/or map sheets. In such an operation, the process of ascertainment of the alignment, dependent upon the survey work and agreement of the commissioners, merges with the procedure of demarcation."

"Moreover, when a joint demarcation commission is mandated to mark a line already described in a written instrument, the commission is sometimes given express authority to vary the alignment in the light of the local circumstances. In the absence of a discretion expressly conferred, the joint commission will almost inevitably make localized adjustments."