Course 1B - Downloading Free Landsat 8 & Sentinel-2 Imagery from this Website and Opening in QGIS
The point of this course is to familiarize yourself with opening imagery in QGIS. Data from this website will be used, as opposed to downloading data from an actual imagery site (this type of download will be done in next course).
1) Acces the Sentinel-2 for ArcGIS page in the SR Tutorials drop-down menu near the top.
2) Click the Landsat 8 / Sentinel-2 Rare Comparison & Data Download link.
3) Click the L8_S2_080415_Comparison.zip link to start downloading data. As mentioned in Course 1A, make sure your browser is set to ask you where to save data, so you can save data to particular folders.
4) Locate the downloaded compressed folder on your computer. It should appear as below.
5) Extract the compressed (zipped) file folder by right-clicking on it. If you need decompression software, we recommend free 7-Zip (outside page; opens in new tab).
6) Open the folder to view the contents.
7) Open QGIS by clicking the folder icon on your desktop. We are using the version that can be downloaded from this website that was described in Course 1A. Access Course 1A is you have questions about QGIS.
8) Double-click QGIS Desktop in the folder to open QGIS. You may need to wait a moment before the software starts opening.
9) The QGIS window will look like this.
10) Click Layer, then naviagate to Add Layer then Add Raster Layer, then click Add Raster Layer and locate the data download.
11) Find the folder from Step 6 to find the Raster Layer.
12) Open the folder.
13) Open the L8_080415_TOA folder to view the contents. Click the LB8 TIFF image, press CTRL and click the L8 B5 TIFF image (to add them both) and click open.
14) The imagery will load in QGIS.
15) Add another raster layer.
16) Locate the LandsatLook_080415 folder.
17) Add the the JPEG image in the folder.
18) The image will appear in QGIS. The file is a LandsatLook "Natural Color" image, where short-wave infrared is color red, infrared is colored green, and red is colored blue (Band 654, RGB). You can learn more about this in a subsequant course.
19) At this point you will want to expand the height of the Layers Panel so all the layers are visible. Click the overlapping squares icon in the upper-right area of the Layers Panel - it will become detached and slightly expand.
20) Hover the cursor over the top edge of the box until the cursor turns to a double-arrow, then click and drag the top up to the desired size.
21) Click and drag the LandsatLook file to the bottom of the Layers Panel. The imagery will be reordered so you can see the Band 4 and 5 images.
22) Add more raster layers.
23) Open the S2_080415_TOA folder to access Sentinel-2 imagery.
24) Click S2_B2 image then press CTRL and scroll down and press the S2_B8 and S2_B8a files to load them all into QGIS.
25) All the images will be loaded into QGIS. Keep in mind that the imagery is for the same day and virtually the same time (15 minutes apart). Also, the imagery has different spatial resolution. Landsat has 30-meter resolution (30 x 30 meter pixels), while Sentinel-2 band 2 and 8 have 10-meter resolution and band 8a has 20-meter resolution. At this point, familiarize yourself with QGIS and the tools - for example, zoom in and out and click pixels with the Identify Features tool (lower case i with a cursor). It is important to spend time using the software with the data until you feel you know the basics. Further courses will described details of imagery, as well as methods of processing and applying.
