[{"data":1,"prerenderedAt":108},["ShallowReactive",2],{"glossary-en-ndvi":3},{"id":4,"title":5,"body":6,"description":94,"extension":95,"meta":96,"navigation":103,"path":104,"seo":105,"stem":106,"__hash__":107},"en_glossary\u002Fen\u002Fglossary\u002Fndvi.md","What is NDVI? Vegetation Indices Explained",{"type":7,"value":8,"toc":85},"minimark",[9,14,22,28,31,36,58,62,77],[10,11,13],"h2",{"id":12},"what-is-ndvi","What is NDVI?",[15,16,17,21],"p",{},[18,19,20],"strong",{},"NDVI (Normalized Difference Vegetation Index)"," is a vigour indicator computed from how a plant responds to near-infrared (NIR) and red light:",[15,23,24],{},[25,26,27],"code",{},"NDVI = (NIR − Red) \u002F (NIR + Red)",[15,29,30],{},"Healthy leaves absorb red light for photosynthesis and strongly reflect NIR. So NDVI is high over healthy vegetation (0.6–0.9), low over soil (0.1–0.2) and negative over water.",[32,33,35],"h3",{"id":34},"other-indices","Other Indices",[37,38,39,46,52],"ul",{},[40,41,42,45],"li",{},[18,43,44],{},"NDRE",": uses the red-edge band instead of red. Shows differences better in dense canopy where NDVI saturates.",[40,47,48,51],{},[18,49,50],{},"GNDVI, GCI",": use the green band; more sensitive to chlorophyll content.",[40,53,54,57],{},[18,55,56],{},"VARI, ExG, GLI, TGI",": computed from RGB bands only; an approximation for cameras without an NIR band.",[32,59,61],{"id":60},"things-to-watch","Things to Watch",[37,63,64,67,74],{},[40,65,66],{},"True NDVI cannot be computed from an RGB camera; a multispectral camera is needed.",[40,68,69,70,73],{},"Comparing NDVI across days requires ",[18,71,72],{},"radiometric calibration",".",[40,75,76],{},"Cloud shadows and low sun angles push the value artificially low.",[15,78,79,80,73],{},"For flight planning and calibration advice, see ",[81,82,84],"a",{"href":83},"\u002Fen\u002Fblog\u002Fmultispectral-drone-ndvi-ndre-plant-health","Plant Health with Multispectral Drones",{"title":86,"searchDepth":87,"depth":87,"links":88},"",2,[89],{"id":12,"depth":87,"text":13,"children":90},[91,93],{"id":34,"depth":92,"text":35},3,{"id":60,"depth":92,"text":61},"How NDVI, NDRE and other vegetation indices are computed, what a multispectral camera can measure, and their limits.","md",{"tags":97},[98,99,100,101,102],"NDVI","Multispectral","Remote Sensing","Precision Agriculture","Drone",true,"\u002Fen\u002Fglossary\u002Fndvi",{"title":5,"description":94},"en\u002Fglossary\u002Fndvi","lo-784vmjP1JggHoQ2GqAmUO-ju6P2zByNzGV50Z2ZQ",1793875325327]