Compute TVDI from dated NDVI and LST raster pairs across multiple dates, then count how many dates/images exceed an area-based threshold such as "more than 40% of pixels have TVDI > 0.7". Use for temporal exceedance-count questions, not yearly trend fitting, single-date percentage reporting, or spike counting on mean TVDI.
Use this when the task asks for a count of dates/images where a drought condition covers more than a given share of the area.
Defaults:
get_filelist once on the task data directory and treat that returned inventory as the source of truth.YYYY-MM-DD date tokens in filenames from that inventory.value_threshold=0.7 and ratio_threshold=40.0.question5/... for data in benchmark/data/question5).Required sequence:
get_filelist on the task data directory exactly once.ndvi_path[], lst_path[], and lists over .output_path[]compute_tvdi call over the full matched set.count_images_exceeding_threshold_ratio using prompt thresholds or defaults value_threshold=0.7 and ratio_threshold=40.0.Hard guardrails:
get_filelist -> compute_tvdi -> count_images_exceeding_threshold_ratio.get_filelist redundantly after already receiving the file inventory.compute_tvdi calls are required, store every returned output path and still execute the final count step before responding.run_python_script, read_file, or any other non-allowed helper/file-inspection tool for this task family.Deterministic completion checklist:
get_filelist completed once.compute_tvdi run for all matched pairs, preferably in one batch call.count_images_exceeding_threshold_ratio called once on the full TVDI list with prompt thresholds or defaults 0.7 and 40.0.Completion rules:
count_images_exceeding_threshold_ratio has been called on the full TVDI output set and the final answer has been emitted.Execution notes:
compute_tvdi into the count step.Example pattern:
get_filelist returns 11 NDVI files and 11 LST files.compute_tvdi over all 11 NDVI paths, 11 LST paths, and 11 output paths.count_images_exceeding_threshold_ratio(image_paths=all_outputs, value_threshold=0.7, ratio_threshold=40.0).4 and the options include C = 4, answer C.Do not use this skill for: