If you look at the entirety of my career the satellite imagery portion has always been lacking. I’ve always been fascinated with satellite imagery like landsat BUT I’ve never used it in any official capacity like running a classification. My first 10 years in GIS was with a mirrored stereoscope and large scale aerial photography. Yes – all manual data collection.
At NRGS I only use imagery as a reference. Most of the time it’s imagery collected from a plane. Occasionally I have to grab something like Landsat to help and it’s a very clunky endeavor.
Over the last 15 years, digging through satellite data has gotten easier. There are several ways to look for it through government/commercial websites and as of lately you’ve probably heard of STAC. STAC (spatio temporal asset catalog) is a common language to describe geospatial information, so it can more easily be worked with, indexed, and discovered (shamelessly stolen from the STAC website).
So what does that have to do with me? I have nothing much to add to STAC except I’ve enjoyed watching it grow. I find things like Google Earth Engine and Microsoft’s Planetary Computer pretty fascinating. What If I could search through Microsoft’s data collection using STAC? Guess What?
Introducing the STAC Plugin written by Kartoza. So for fun I added the OSM background to QGIS and then navigated to Chattanooga. From there you can search a STAC provider by location and date. I’m going to use the default Microsoft Planetary Computer STAC connection. Yes – I did chuckle as I’m using an Open Source GIS Desktop running on an Open Source Operating System to search something at Microsoft.
Let’s search Sentinel 2 data for Chattanooga during December.
It looks like December 25th has very little cloud cover. I’ll download bands 2, 3, and 4 (be sure you set a download directory before doing this).
If I use the “Build Virtual Raster Tool” I can combine bands 2 3 4 into something recognizable.
….and I don’t know entirely what I’m doing and here is a Sentinel 2 Image in color. What is the white stuff? Snow. We actually had a dusting of snow on Dec 24th. For a more complete explanation of the STAC Plugin go here. For even more fun install the plugin in QGIS and download some imagery.
