Compare calculators

Both calculators run independently — change the inputs on either side to compare results.

Horizon Distance Calculator

Calculate the maximum distance at which an observer can see a target object over the horizon, based on both their heights above sea level. Ideal for navigation, broadcasting tower placement, and outdoor planning.

Observer Height (m)

Target Height (m)

Fill in the required fields to see your result.

Geography

Vegetation Index Calculator

Calculate the Normalized Difference Vegetation Index (NDVI) from near-infrared and red reflectance values. Used in remote sensing and ecology to assess plant health, biomass, and land cover change.

Near-Infrared Reflectance

Red Reflectance

Fill in the required fields to see your result.

Key differences

	Horizon Distance Calculator	Vegetation Index Calculator
Category	Geography	Geography
Inputs required	2	2
Result	Visibility Distance (km)	NDVI
What it does	Calculate the maximum distance at which an observer can see a target object over the horizon, based on both their heights above sea level. Ideal for navigation, broadcasting tower placement, and outdoor planning.	Calculate the Normalized Difference Vegetation Index (NDVI) from near-infrared and red reflectance values. Used in remote sensing and ecology to assess plant health, biomass, and land cover change.