Start exploring options for depth data, #48.

data-raw/depth/depth.R

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+# Create an object of depth values, based on grid26.
+
+load_all()
+library(PBSdata)   # devtools::install_github("pbs-software/pbs-data/PBSdata")
+library(PBSmapping)
+
+grid26   # sf object
+
+vignette('PBSdata-UG', package = "PBSdata")
+# Page 5 says:
+# Figure 2. Data frame of sea floor topography (Smith and Sandwell, 1997) downloaded from
+# TOPEX and reformatted for use by makeTopography in PBSmapping .
+# and gives example code. Also
+# ?bctopo
+# gives the Smith and Sandwell 1997 reference.
+
+# Probably better to use more recent data, and process it once (PBSdata already
+# processed values).
+
+# Philina suggested marmap. Looking at first vignette it talks about raster and
+# sp packages (but not sf).
+
+# Search on Canadian Hydrographic Service gives S102and111.zip from
+#  https://www.charts.gc.ca/data-gestion/index-eng.html
+#  S102/ contains .h5 files. Can read these in using the rhdf5 package
+#  https://www.bioconductor.org/packages/release/bioc/vignettes/rhdf5/inst/doc/rhdf5.html
+# install.packages("BiocManager")
+# BiocManager::install("rhdf5")
+
+library(rhdf5)    # vignette at
+# https://www.bioconductor.org/packages/release/bioc/vignettes/rhdf5/inst/doc/rhdf5.html
+a <- H5Fopen("S102_S111sample/S102/102CA0024600N07100W.h5")