Spatial Data and GIS

Work with MODIS remote sensing data in in R.

In this lesson we will explore how to import and work with MODIS remote sensing data in raster geotiff format in R. We will cover importing many files using regular expressions and cleaning raster stack layer names for nice plotting.

last updated: 12 May 2017

Clean remote sensing data in R - Clouds, shadows & cloud masks

In this lesson, we will learn how to deal with clouds when working with spectral remote sensing data. We will learn how to mask clouds from landsat and MODIS remote sensing data in R using the mask() function. We will also discuss issues associated with cloud cover - particular as they relate to a research topic.

last updated: 04 May 2017

Adjust plot extent in R.

In this lesson we will review how to adjust the extent of a spatial plot in R using the ext() or extent argument and the extent of another layer.

last updated: 12 May 2017

Plot grid of spatial plots in R.

In this lesson we cover using par() or parameter settings in R to plot several raster RGB plots in R in a grid.

last updated: 12 May 2017

Calculate a remote sensing derived vegetation index in R

A vegetation index is a single value that quantifies vegetation health or structure. In this lesson, we will review the basic principles associated with calculating a vegetation index from raster formated, landsat remote sensing data in R. We will then export the calculated index raster as a geotiff using the writeRaster() function.

last updated: 12 May 2017

Landsat remote sensing tif files in R

In this lesson we will cover the basics of using LAndsat 7 and 8 in R. We will learn how to import landsat data stored in .tif format - where each .tif file represents a single band rather than a stack of bands. Finally we will plot the data using various 3 band combinations including RGB and color-infrared.

last updated: 12 May 2017

Extract raster values using vector boundaries in R

This lesson reviews how to extract pixels from a raster dataset using a vector boundary. We can use the extracted pixels to calculate mean and max tree height for a study area (in this case a field site where we measured tree heights on the ground. Finally we will compare tree heights derived from lidar data compared to tree height measured by humans on the ground.

last updated: 12 May 2017

GIS in R: Plot spatial data and create custom legends in R

In this lesson we break down the steps required to create a custom legend for spatial data in R. We discuss creating unique symbols per category, customizing colors and placing your legend outside of the plot using the xpd argument combined with x,y placement and margin settings.

last updated: 12 May 2017

GIS in R: Projected vs geographic Coordinate Reference Systems

This tutorial describes key differences between projected and geographic coordinate reference systems (CRSs). We focus on the Universal Trans Mercator (UTM) projected Coordinate Reference which divides the globe into zones to optimize projection results in each zone and WGS84 which is a geographic (latitude and longitude) CRS. It also briefly introduces the concept of a datum.

last updated: 12 May 2017

Classify a raster in R.

This lesson presents how to classify a raster dataset and export it as a new raster in R.

last updated: 12 May 2017

Introduction to spatial metadata embedded within tif tags - raster data in R

This lesson introduces the concept of metadata - or data about the data. Metadata describe key characteristics of a data set. For spatial data these characteristics including CRS, resolution and spatial extent. Here we discuss the use of tif tags or metadata embedded within a geotiff file as they can be used to explore data programatically.

last updated: 12 May 2017

Introduction to lidar raster data products

This lesson covers the 3 key lidar raster products including the canopy height model (CHM) the digital terrain model (DTM or DEM) and the Digital Surface Model (DSM). Finally, it demonstrated how to open a lidar raster dataset in R.

last updated: 12 May 2017

How to download and install QGIS

QGIS is a free, open-souce GIS tool that is comparable to ArcMap. This lesson walks through how to install QGIS on your computer.

last updated: 30 Dec 2016