The Square Scan Algorithm (SSA) was the first algorithm used to transform line features into vector representations automatically without any help from the user and without any use of other devices for instance, digitizer [1]. This paper presents some important modifications to the SSA algorithm. The main modification is done by drawing continuous squares to detect lines or branches without any lost segments. While the SSA draws each square after a distance called step length. The obtained performance was better and the processing time was reduced to less than the half approximately comparing to the previous SSA algorithm. The proposed algorithm may help with the integration of remotely sensed data and geographic information systems (GIS).

Keywords: line extraction, raster-to-vector, vectorization, feature detection, GIS databases, and Square Scan Algorithm.