01-introduction.Rmd

# Introduction

**This guide is intended to introduce the basics of running LandTrendr (LT) in Google Earth Engine (GEE). 
It describes the LT conceptual framework, what is required to run LT-GEE, how to run it, 
what the outputs are, and how they are formatted. It also provides three example scripts,
a series of user interfaces to LT operations, and an API for opinionated, but easy use.**

LandTrendr is set of spectral-temporal segmentation algorithms that are useful 
for change detection in a time series of moderate resolution satellite imagery (primarily Landsat) 
and for generating trajectory-based spectral time series data largely absent of 
inter-annual signal noise. 
LT was originally implemented in IDL (Interactive Data Language), 
but with the help of engineers at Google, it has been ported to the GEE platform 
([porting paper](http://www.mdpi.com/2072-4292/10/5/691); [GEE overview](https://earthengine.google.com/); [GEE paper](https://www.sciencedirect.com/science/article/pii/S0034425717302900)). 
The GEE framework nearly eliminates the onerous data management and image-preprocessing 
aspects of the IDL implementation. It is also light-years faster than the IDL 
implementation, where computing time is measured in minutes instead of days.

We assume that you have a [GEE account](https://signup.earthengine.google.com/#!/), 
that you are somewhat familiar with the [GEE JavaScript API](https://developers.google.com/earth-engine/), 
and have a basic understanding of LandTrendr ([method](http://geotrendr.ceoas.oregonstate.edu/files/2015/05/Kennedy_etal2010.pdf), 
[application](http://geotrendr.ceoas.oregonstate.edu/files/2015/05/kennedy_etal_2012_nwfp.pdf)).