(7) Spinning Earth showing crustal ages¶

Animation of a spinning Earth showing the crustal ages from EarthByte for the oceans and topographic relief on land, with shading given by the global relief and modified by position relative to an artificial sun in the east. A progress slice is added as well. We add a 1 second fade in and a 1 second fade out for the animation

DEM: @earth_relief_02m
Ages: @earth_age_02m.grd

The resulting movie was presented at the Fall 2019 AGU meeting in an eLighting talk: P. Wessel, 2019, GMT science animations for the masses, Abstract IN21B-11. The finished movie is available in our YouTube channel as well (without fading): https://youtu.be/KfBwQlyjz5w The movie took ~2.5 hours to render on a 24-core MacPro 2013.

#!/usr/bin/env bash
#
## Animation of a spinning Earth showing the crustal ages from EarthByte for the oceans
# and topographic relief on land, with shading given by the global relief and modified
# by position relative to an artificial sun in the east.  A progress slice is added as well.
# We add a 1 second fade in and a 1 second fade out for the animation
# DEM:   @earth_relief_06m
# Ages:  @earth_age_06m
# A similar movie was presented at the Fall 2019 AGU meeting in an eLighting talk:
# P. Wessel, 2019, GMT science animations for the masses, Abstract IN21B-11.
# The finished movie is available in our YouTube channel as well (without fading):
# https://youtu.be/KfBwQlyjz5w
# The movie takes about ~20 minutes to render on a 24-core MacPro 2013.
# The higher resolution movie on YouTube used the 02m data set resolution.

# 1. Create background plot and data files needed in the loop
cat << EOF > pre.sh
gmt begin
	# Set view and sun longitudes
	gmt math -T-12/372/0.5 -I T 5 SUB = longitudes.txt
	# Extract a topography CPT
	gmt makecpt -Cdem2 -T0/6000 -H > z.cpt
	# Get gradients of the relief from N45E
	gmt grdgradient @earth_relief_06m -Nt1.2 -A45 -Gintens.grd
gmt end
EOF
# 2. Set up main script
cat << EOF > main.sh
gmt begin
	# Let HSV minimum value go to zero and faint map border
	gmt set COLOR_HSV_MIN_V 0 MAP_FRAME_PEN=faint
	# Fake simulation of sun illumination from east added to relief intensities
	gmt grdmath intens.grd X \${MOVIE_COL1} SUB SIND 0.8 MUL ADD 0.2 SUB = s.nc
	# Plot age grid first using EarthByte age cpt
	gmt grdimage @earth_age_06m -Is.nc -JG\${MOVIE_COL0}/15/10.8c -X0 -Y0
	# Clip to expose land areas only
	gmt coast -G -Di
	# Overlay relief over land only using dem cpt
	gmt grdimage @earth_relief_06m -Is.nc -Cz.cpt
	# Undo clipping and overlay gridlines
	gmt coast -Q -B30g30
gmt end show
EOF
# 3. Run the movie, requesting a fade in/out via white
gmt movie main.sh -Sbpre.sh -C10.8cx10.8cx100 -Tlongitudes.txt -Nanim07 -Lf -K+gwhite -H8 -Pa+w1c+Gwhite -Fmp4 -V -W -Zs