Streaming_cloud_optimized_geotiffs_using_QGIS.md

Streaming NASA Earthdata Cloud-Optimized Geotiffs using QGIS

Note: Users must have NASA Earthdata Login to stream data.

QGIS can be used to stream NASA Earthdata cloud-optimized geotiff files. To do this QGIS uses https and the vsicurl virtual file system handler. This guide will show you how to configure QGIS to do this. There are 4 steps needed.

1. Create a .netrc file
2. Add Custom Environment Variables
3. Restart QGIS
4. Add Data

1. Create a .netrc file

Under the hood QGIS uses gdal and vsicurl to stream data via https. For NASA Earthdata, this requires a .netrc file to store your Earthdata login credentials. If you already have one, you can skip this step. This file should be located in your home directory. Choose one of the methods below to create the file and enter your credentials.

A. Manual Set Up

• Download the .netrc template file and save it in your home/user/ directory, where user is your personal user directory. For example: C:\Users\user\.netrc or home/user/.netrc.
• Open the .netrc file in a text editor and replace with your NASA Earthdata Login username and with your NASA Earthdata Login password.

After editing, the file should look something like this:

or you can also have everything on a single line separated by spaces, like:

B. Command Line

For Linux/MacOS:

To Create a .netrc file, enter the following in the command line, replacing and with your NASA Earthdata username and password. This will create a file in your home directory or append your NASA credentials to an existing file.

echo "machine urs.earthdata.nasa.gov login <USERNAME> password <PASSWORD>" >>~/.netrc

For Windows:

To Create a .netrc file, enter the following in the command line, replacing and with your NASA Earthdata username and password. This will create a file in your home directory or append your NASA credentials to an existing file.

echo machine urs.earthdata.nasa.gov login <USERNAME> password <PASSWORD> >> %userprofile%\.netrc

You can verify that the file is correct by opening with a text editor. It should look like an example in one of the figures above.

2. Environment Settings

Next, while still in the Settings menu, select System on the left-hand side, then scroll down to Environment. Select the check box and enter the Variables and Values in the table below by clicking the plus sign to add a new variable. These variables, set up a place for cookies to be stored and read from, prevent GDAL from reading all files in the directory, specify the extensions GDAL is allowed to access over HTTPS using the vsicurl virtual file system handler, and allow use of unsafe SSL connections (use with caution).

Variable	Value
GDAL_HTTP_COOKIEFILE	~/cookies.txt
GDAL_HTTP_COOKIEJAR	~/cookies.txt
GDAL_DISABLE_READDIR_ON_OPEN	EMPTY_DIR
CPL_VSIL_CURL_ALLOWED_EXTENSIONS	TIF
GDAL_HTTP_UNSAFESSL	YES

Note: These settings may affect streaming from other data sources.

3. Restart QGIS

Restart QGIS to load the new environment settings.

4. Add Some Data

To add some raster data, select the add raster data button from the toolbar, select 'Protocol: HTTP(S), cloud, etc' as the source type, then enter a URI for a cloud-optimized geotiff file and press the add button. For example:

https://data.lpdaac.earthdatacloud.nasa.gov/lp-prod-protected/EMITL2BCH4ENH.001/EMIT_L2B_CH4ENH_001_20240423T074559_2411405_018/EMIT_L2B_CH4ENH_001_20240423T074559_2411405_018.tif

This should add the data to your map, and will work with any NASA Earthdata hosted cloud-optimized geotiff file.

If these instructions do not work, please verify that your .netrc file has the correct username and password, and is formatted as shown in Section 1.

Contact Info

Email: LPDAAC@usgs.gov
Voice: +1-866-573-3222
Organization: Land Processes Distributed Active Archive Center (LP DAAC)¹
Website: https://lpdaac.usgs.gov/
Date last modified: 06-25-2024

¹Work performed under USGS contract 140G0121D0001 for NASA contract NNG14HH33I.