This book presents a selection of high-quality, peer-reviewed papers from the 9th International Conference on Geoinformatics and Data Analysis (ICGDA 2026), held in Lyon, France, from April 13-15, 2026. This book covers a wide range of topics including Geospatial Data Analysis and Modeling, Geospatial Multimodal Data Analysis, Modeling Methods, and Security Management, Remote Sensing-based Spatial Data Analysis and Intelligent Communication Technologies, Geographic information retrieval, T...

This resource offers a groundbreaking effort to make mathematics education research on ratios and proportions readily accessible and understandable to preservice and in-service teachers of grades 6 to 8. Using extensive annotated samples of student work and based on research gathered in the Ongoing Assessment Project (OGAP), A Focus on Ratios and Proportions teaches readers how students develop understanding and fluency involving ratio and proportion concepts.Special featu...