a few quick notes

espm-288 · Feb 21, 2024 · 4785aab · 4785aab
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diff --git a/_freeze/notebook/fire-example/execute-results/html.json b/_freeze/notebook/fire-example/execute-results/html.json
diff --git a/notebook/fire-example.qmd b/notebook/fire-example.qmd
@@ -12,6 +12,7 @@ library(gdalcubes)
 ```
 
 
+
 ```{r}
 
 url <- "https://34c031f8-c9fd-4018-8c5a-4159cdff6b0d-cdn-endpoint.azureedge.net/-/media/calfire-website/what-we-do/fire-resource-assessment-program---frap/gis-data/april-2023/fire221gdb.zip?rev=9e3e1e5e61e242d5b2994d666d72a91a&hash=F424990CD64BB7C4CF01C6CE211C0A59"
@@ -41,11 +42,19 @@ fire_jtree <- fire_polys |> filter(fire_is_in_jtree)
 
 
 ```{r}
-tmap_mode("plot")
+tmap_mode("view")
 tm_shape(jtree) + tm_polygons() + 
  tm_shape(fire_jtree) + tm_polygons("YEAR_")
 ```
 
+Because burned vegetation presents a very different spectral pattern to normal vegetation, burn intensity can be measured by comparing the spectra in different bands.  The greatest contrast between burned and health vegetation can be seen in the NIR and SWIR bands, as seen in this typical spectral response curve:
+
+
+![](nbr.png)
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+The normalized burn ratio (NBR) is defined as the ratio:
+
+$$ NBR = \frac{NIR - SWIR}{NIR + SWIR}$$
 
 
 ## Landsat example

diff --git a/notebook/nbr.png b/notebook/nbr.png