# Incidence matrix import

Incidence matrix is a matrix structure used to model graphs. Incidence matrix column represents a graph edge and row a graph node. Thus, if matrix has four columns, it also models a graph with four edges. If matrix has seven rows, it models a graph with seven nodes. Thinking now of a single column, representing one edge. If column cell contains a value of 1 (one), the column represents an edge connecting to the node the row of cell represents. For example, if an incidence matrix has a cell at second column and third row with a value 1, then graph's second edge connects graph's third node. Compared to adjacency matrix, an incidence matrix can model edges with more than two nodes. Saying this in terms of topic maps, incidence matrix can represent not only binary associations but n-ary associations in general.

Wandora's incidence matrix import feature starts with menu option **File > Import > Incidence matrix import**. Matrix cell values are separated with space characters and rows with new line character. Association type is generic one and you can change it in Wandora to reflect your semantic view. Also roles are generic ones you might want to change after incidence matrix import.