Nice job! Normally, I would expect that one would use bands 5 and 4 for Landsat 8. I'm assuming you made some previous definitional modifications in your band data to arrive at a 4 and 1 combination. I was just interested in what you did. Also, I like reversing the ribbon for the symbology that you selected to show vigorous vegetation as blue rather than red. Anyway I know it is a preferential thing. I've subscribed to your site because you go slow (for us older folks) and you are straight to the point. Thanks!
Thanks a lot for your feedback! Yes you're right, I made definitional modifications and will be sure to always mention such elements in my future videos.
That's a great question Wycliffe. I have used two different approaches. So for the first result (2017 image) with the result -1 to 1, I have used the "Scientific output option" while for the second result (2019 image) I have used the ArcGIS Pro default equation used to generate the output which is as follows:
NDVI = ((IR - R)/(IR + R)) * 100 + 100 . This results in a value range of 0 to 200. This value range fits within an 8-bit data structure, which can easily be rendered with a specific color ramp or color map.
Nice job! Normally, I would expect that one would use bands 5 and 4 for Landsat 8. I'm assuming you made some previous definitional modifications in your band data to arrive at a 4 and 1 combination. I was just interested in what you did. Also, I like reversing the ribbon for the symbology that you selected to show vigorous vegetation as blue rather than red. Anyway I know it is a preferential thing. I've subscribed to your site because you go slow (for us older folks) and you are straight to the point. Thanks!
Thanks a lot for your feedback! Yes you're right, I made definitional modifications and will be sure to always mention such elements in my future videos.
Nice job. What could be the reason why NDVI values for 2017 ranged from
-1 to 1 while that of 2019 ranged from 0 to 200?
That's a great question Wycliffe. I have used two different approaches. So for the first result (2017 image) with the result -1 to 1, I have used the "Scientific output option" while for the second result (2019 image) I have used the ArcGIS Pro default equation used to generate the output which is as follows:
NDVI = ((IR - R)/(IR + R)) * 100 + 100
.
This results in a value range of 0 to 200. This value range fits within an 8-bit data structure, which can easily be rendered with a specific color ramp or color map.
@@WencelausSimiyu Thanks for the detailed response ✅, I get it now.
You're welcome