What is an important factor to ensure when integrating multiple data layers in GIS?

Matching coordinate systems is crucial when integrating multiple data layers in GIS because it ensures that all layers align spatially. Each layer may originate from different sources or be created using various methods, resulting in distinct coordinate systems. If these systems do not match, the data will not overlay correctly, leading to inaccurate analysis and visual representation. For example, one layer might use a geographic coordinate system based on latitude and longitude, while another could use a projected coordinate system suited for a specific region. Aligning these systems allows for accurate spatial analysis and mapping.

Common graphic display settings, software compatibility, and data source reliability are all important factors in GIS, but they do not directly address the foundational need for spatial alignment of the data layers. Without matching coordinate systems, even the most reliable data or compatible software will not produce meaningful results.