To help designers and planners better understand the composition and spatial context of planning sites, a GIS-based synthesized tool combining qualitative and quantitative methods is adaptively developed based on the Form Syntax tool to take accessible OpenStreetMap and Ordnance Survey data and to provide ordinal categorical assessment results of high/medium/low degrees. The morphological measurement tool is assembled within the qualitative framework proposed by J. Jacobs with advanced quantitative methods measuring street configuration using betweenness of Space Syntax method, building density and typology using FSI, GSI of Spacematrix method, and functional mixture using MXI (mixed-use index). The approach is validated with regression analyses focusing on relationship between morphological elements and urban vitality through a comparison to recent researches through the case study of London. The analysis results reflected on map series suggest the existence of ring-structure gradient of building density, and typology in the study area and the association among morphological elements. The synthesized method has proved the capacity of diagnostic function for block-level urban design and spatial context analysis of urban planning and redevelopment projects. This research deploys a threedimensional lens through the decomposition and synthesis, providing a relationship-prioritized perspective to investigate the complexity of urban environments and the interaction with socio-economic performance.