Update to activate NDVI functionality

NetworkGenerator.R

@@ -21,8 +21,7 @@ makeNetwork<-function(city, outputSubdirectory = "generated_network"){
   #   (only supported for Victoria at this stage)
   # •	demFile: if 'addElevation=T', digital elevation model raster file (must be 
   #   in same coordinate system as network)
-  # •	ndviFile: if 'addNDVI=T', raster file with NDVI values (must be in same
-  #   coordinate system as network)
+  # •	ndviFile: if 'addNDVI=T', raster file with NDVI values
   # •	gtfs_feed: if 'addGtfs=T' or 'addDestinationLayer=T, zip file containing 
   #   GTFS data (and, if 'addGtfs=T', also set start and end dates in GTFS section)
 
@@ -33,7 +32,7 @@ makeNetwork<-function(city, outputSubdirectory = "generated_network"){
     unconfiguredSqlite = "./output/bendigo_network_unconfigured.sqlite"
     cropAreaPoly = ""  # must set 'crop2Area=F'
     demFile = "./data/dem_bendigo.tif" 
-    # ndviFile = ""  # must set 'addNDVI=F'
+    ndviFile = "./data/NDVI_Bendigo_2023.tif" 
     gtfs_feed = "./data/gtfs.zip"
 
   } else if (city == "Melbourne") {
@@ -43,7 +42,7 @@ makeNetwork<-function(city, outputSubdirectory = "generated_network"){
     unconfiguredSqlite = "./output/melbourne_network_unconfigured.sqlite"
     cropAreaPoly = "city-of-melbourne_victoria"
     demFile = "./data/dem_melbourne.tif"
-    # ndviFile = "./data/NDVI_1600mBuffer_Melbourne_reprojected.tif"
+    ndviFile = "./data/NDVI_Melbourne_2023.tif"
     gtfs_feed = "./data/gtfs.zip"
 
   } else {
@@ -92,7 +91,7 @@ makeNetwork<-function(city, outputSubdirectory = "generated_network"){
 
   # NDVI
   # A flag for whether to add NDVI or not
-  addNDVI=F
+  addNDVI=T
   # Buffer distance for finding average NDVI for links
   ndviBuffDist=30
 
@@ -284,7 +283,8 @@ makeNetwork<-function(city, outputSubdirectory = "generated_network"){
   if(addNDVI) {
     system.time(networkDensified[[2]] <- addNDVI2Links(networkDensified[[2]],
                                                        ndviFile,
-                                                       ndviBuffDist))
+                                                       ndviBuffDist,
+                                                       outputCrs))
   }
 
   # adding destinations layer

data/README.md

@@ -11,7 +11,7 @@ Download the following files for the relevant network location.
 |--------------------------|---------------------------------------------------|
 | greater_bendigo.sqlite   | Boundary of the Greater Bendigo Local Government Area |
 | dem_bendigo.tif          | Digital elevation model data for the Greater Bendigo area |
-| [to come]                | [NDVI] data for the Greater Bendigo area              |
+| NDVI_Bendigo_2023.tif    | NDVI data for the Greater Bendigo area              |
 | gtfs.zip                 | GTFS feed for Victoria as at 20 October 2023      |
 
 
@@ -20,7 +20,7 @@ Download the following files for the relevant network location.
 |--------------------------|---------------------------------------------------|
 | greater_melbourne.sqlite | Boundary of the Greater Melbourne Greater Capital City Statistical Area |
 | dem_melbourne.tif        | Digital elevation model data for the Greater Melbourne area |
-| [to come]                | [NDVI] data for the Greater Melbourne area        |
+| NDVI_Melbourne_2023.tif  | NDVI data for the Greater Melbourne area        |
 | gtfs.zip                 | GTFS feed for Victoria as at 20 October 2023      |
 
 
@@ -38,3 +38,5 @@ The file `data/data prep tools.R` contains:
 * the script used to extract the region boundary files from the LGA and GCCSA files above, and
 * the script used to crop the digital elevation files from a DEM file for the whole of Victoria (available for download from https://discover.data.vic.gov.au/dataset/vicmap-elevation-dem-10m, 9.3 GB).  
 Those scripts may also be useful to generate similar data input files for other locations if required.
+
+The NDVI files were created from Sentinel 2 data using Google Earth Engine at https://code.earthengine.google.com/.

functions/addNDVI.R

@@ -1,17 +1,18 @@
 # function to add NDVI to links, where NDVI is the average of the NDVI
 # values within a 30m buffer of the links
 
-addNDVI2Links <- function(links, ndviFile, ndviBuffDist) {
+addNDVI2Links <- function(links, ndviFile, ndviBuffDist, outputCrs) {
 
   # links = networkDensified[[2]]
-  # ndviFile = "./data/NDVI_1600mBuffer_Melbourne_reprojected.tif"
+  # ndviFile = "./data/NDVI_Bendigo_2023.tif"
   # ndviBuffDist = 30
 
-  echo("Reading in the NDVI file\n")
+  echo("Reading in the NDVI file and reprojecting if necessary\n")
 
-  # read in NDVI file
+  # read in NDVI file, and convert to outputCrs if necessary
   ndvi <- rast(ndviFile)
-
+  if (!same.crs(ndvi, outputCrs)) ndvi <- project(ndvi, outputCrs)
+
   # buffer each link
   links.buffered <- st_buffer(links, 30)