| KRATKA VSEBINA | Visibility site analysis is an important research topic with many applications in Geographical Information Systems. The paper introduces a new paradigm in terrain guarding called k-guarding. K -guarding is a generalization of the classic guarding problem where, instead of only one guard, each surface patch is guarded by at least k guards. Afterwards, two optimization problems based on k-guarding are defined: an optimum k-guarding, and a constrained k-guarding. There are three heuristic approaches - k-greedy add, k-stingy drop, and k-reverse greedy - that are proposed as a solution to the above mentioned optimization problems. The first two are known approaches adapted to k-guarding, while k-reverse greedy is a new, original heuristic. The heuristics are compared using actual topographic surfaces. It is shown thatour approach (k-reverse greedy) gives on average the best near optimum solutions. The most surprising finding of the experiments is that the combination of heuristics which are here introduced yields even better results. // Analiza vidnosti je pomembno področje raziskovanja z veliko aplikacijami v Geografskih Informacijskih Sistemih. Prispevek uvaja novo paradigmo v varovanju terenov imenovano k-varovanje. K-varovanje je posplošenje klasičnega problema varovanja terena, kjer namesto enega stražarja vsako krpo površja varuje vsaj k stražarjev. Zatem definiramo dvaoptimizacijska problema na podlagi k-varovanja: optimalno k-varovanje in k-varovanje z omejitvami. Kot rešitev so predlagani trije hevristični pristopi - k-greedy add, k-stingy drop in k-reverse greedy. Prva dva sta znana pristopa, prirejena za k-varovanje, medtem ko je k-reverse greedy nova, originalna hevristika. Hevristike smo primerjali na realnih topografskih površjih. Pokazali smo, da naš pristop (k-reverse greedy) v povprečju daje rezultate, ki so najbližje optimalnim. Najbolj presenetljivoodkritje eksperimentov je, da kombinacija različnih, tukaj predstavljenih hevristik, daje celo boljše rezultate. |