How to read and export image metadata with Exiftool

Introduction

MicaSense raw images have a wealth of useful information including imager information, irradiance measurements, GPS coordinates, and more. Note that this is not a necessary step in processing your images in photogrammetry software such as Pix4Dmapper or Agisoft Metashape but is a useful option for being able to view the information stored in your images for analysis.

In order to view and extract this information, you will need special software that allows you to view and edit EXIF data in your images. There are many solutions out there, but we prefer one called ExifTool by Phil Harvey. 

Once installed in your operating system of choice, you will have the ability to use the command line to quickly view and export your desired metadata. Below are some examples of common usages and expected outputs.

 

Examples

These examples assume you have navigated to the directory containing your raw images from your MicaSense camera. These commands work on Mac and Linux terminals alike. 

Viewing all metadata of a particular image 

exiftool IMG_0000_1.tif

This will return all the metadata tag names and its associated values for the specified image.

If you want to see the data for all bands of a particular capture, you can use a wildcard as follows:

exiftool IMG_0000_*.tif

 

Showing specific tags of an image

Sometimes, you want to see only a specific tag. Let's say I want to see all Irradiance data from a DLS2. Here we use the -i flag to make our search term case-insensitive.

exiftool IMG_0000_1.tif | grep -i irradiance

Irradiance : 153.76076942636834
Irradiance Yaw : -45.375802202125556
Irradiance Pitch : -3.5261545901600879
Irradiance Roll : 1.3356333488334389
Spectral Irradiance : 153.76076942636834
Horizontal Irradiance : 173.21219853141869
Direct Irradiance : 154.06163068522613
Scattered Irradiance : 35.581307906058925

 

Or if I want to instead see some GPS information

exiftool IMG_0000_1.tif | grep -i gps

GPSXY Accuracy : 1.1139999628067017
GPSZ Accuracy : 1.3179999589920044
GPS Version ID : 2.2.0.0
GPS Latitude Ref : North
GPS Longitude Ref : West
GPS Altitude Ref : Above Sea Level
GPS Dilution Of Precision : 0
GPS Altitude : 0.2 m Above Sea Level
GPS Latitude : 47 deg 55' 46.21" N
GPS Longitude : 122 deg 10' 1.88" W
GPS Position : 47 deg 55' 46.21" N, 122 deg 10' 1.88" W

 

Exporting data to a CSV file

In order to export all the data in a spreadsheet, you can use the following command:

exiftool -r -all -csv *.tif > metadata.csv

By default, Exiftool converts some values into more human-readable format such as 

GPS Latitude: 47.9295011 converts to 47 deg 55' 46.20" N

If you prefer to have the decimal degrees instead, simply add the -n flag

exiftool -r -n -all -csv *.tif > metadata.csv

 

More questions?

If you still have some questions about the MicaSense metadata please contact us !

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