Welsh Journals

TABLE 2: INDICES OF CONNECTIVITY, 1795. ASSOCIATED GROSS VERTEX NODE SHIMBEL INDEX NUMBER ACCESSIBILITY I II I II I II A. ABER 53 89 6 8 1347 4857 B. BANGOR 65 106 7 9 590 2471 C. CAERNARFON 79 125 8 10 252 1075 D. MENAIBRIDGE 53 77 6 6 2579 8741 E. BEAUMARIS 43 74 5 7 2850 9110 F. TAILAWR* 25. 61 4 6 6930 17488 G. CEINT* 39 53. 5 5. 6854 21373 H. PENTRE BERW 75 6 10469 I. NEWBOROUGH 53 94 6 7 2579 4188 J. TREFORLLWYD* 66 6 12288 K. LLANGEFNI 39 61 6 6 8068 16117 L. LLANERCHYMEDD 35 67 5 6 8746 12329 M. AMLWCH 49 86 6 7 3256 5186 N. LLANDRYGAN* 70 7 13587 O. YNYSPORTH* 45 62 7 7 6037 18656 P. LLANGRISTIOLUS* 79 8 8828 Q. LLANGADWALADR 59 98 8 9 2233 3678 R. ABERFRAW 55 86 7 9 2522 8401 S. LLANBEULAN 41 67 6 8 7345 19887 T. LLANFAETHLU 95 8 6179 U. HOLYHEAD 55 103 7 10 2522 3920 V. VALLEY 84 9 10075 I. Real Nodes. II. Including induced or 'floating' nodes (see text). Hamlet of Parish name given to node for identification purposes. of nodes. Utilising the procedure for deriving a modified accessibility index based on both direct and indirect connections between nodes developed by Shimbel and Katz (1953) the powered matrix provides accessibility indices for each node in the network. From the shortest-path matrix the accessibility indices were extracted. Firstly the Shimbel Index, the sum of the cells in each column, was computed for each node, together with the Associated Number, which is the highest cell value in each column. These indices were used to identify the changes in the hierarchy of accessibility consequent upon changes within the transport network in Anglesey and Arfon. It will be seen that the Shimbel Index provides greater differentiation between the centres and would, in the analysis, appear to be the more useful. As this index represents the sum of the shortest paths from a node to all other nodes then a low value indicates a high degree of accessibility. The node with the