AEM Strategy

Mapping & Classification Strategy

AEM is based on an iterative process of feature mapping and classification by image interpretation and groundtruthing.

Overview

AEM is a resource-intensive procedure that requires high-resolution imagery, trained interpreters, and extensive fieldwork. For this reason AEM is best applied to areas smaller than 100 km², and is usually initiated by stratifying sites and regions into sample units that will be mapped, usually 500 × 500 m square sample cells. After sample cells are selected for mapping, high resolution imagery (≤ 1 m) is prepared for each cell.

Ecotope mapping begins with the preparation of a current map, and proceeds in four stages, each of which requires a full cycle of feature mapping and classification by image interpretation and groundtruthing. Historical maps are prepared after completing current maps, by a similar procedure, but with groundtruthing by elder interviews and field visits. After preparing current and historical ecotope maps, landscape changes can be mapped.

Note that before beginning ecotope mapping, mappers must be trained at two or more different sites by repeated mapping and map validation against a reference map to develop conformance with mapping standards and to calibrate results across mappers.

Strategy

Sample Cell Selection
Image Preparation
Mapper Training
Current Ecotope Mapping

Reconnaissance
Initial Mapping
Draft Mapping
Final Mapping

Historical Ecotope Mapping

Initial Mapping
Elder Visit
Draft Mapping
Final Mapping

Measure Change

Citation for AEM: Ellis E. C., H. Wang, H. Xiao, K. Peng, X. P. Liu, S. C. Li, H. Ouyang, X. Cheng, and L. Z. Yang. 2006. Measuring long-term ecological changes in densely populated landscapes using current and historical high resolution imagery. Remote Sensing of Environment 100(4):457-473.