3d Fly-by

[Markus Neteler]

On Sun, 14 Mar 1999, Tom Gewecke wrote:

> Has anyone used a sequence of different d.3d commands to create a sort of
> fly-by over a topographic surface?  What is the best way to save the d.3d
> images from the GRASS monitor to a set of files that could be used for a
> "movie?"  I'm using Linux and GRASS 5.  Thanks for any advice.
> tom at bluesky.org

Yes: GRASS 4.2.1 source code package:
src421/untested/scripts/d.3d.fly

Find the script attached, you have to configure it a bit.
You can create MPEGs from it, if you like.

Hope this helps

  Markus
 
 
 
-------------- next part --------------
#!/bin/sh
#
# Usage: d.3d.fly image elevationmap
if test "$GISBASE" = ""; then
echo "You Must be in GRASS to run this program."
exit
fi

# test: all parameters specified?
if test "$1" = ""; then
      echo ""
      echo "GRASS script for 3D fly over terrain with MPEG film output"
      echo ""
      echo "Usage: d.3d.fly  image  elevationmap"
      echo "       Change coordinates within the script."
      echo ""
      exit
fi

###########################################################
# Example script to create a series of 3D gif images in
# GRASS for subsequent animation with xanim, animate or 
# create MPEG film with mpeg_encode (src.related/mpeg_encode)
#
# This script uses the GRASS CELL monitor to capture
# output from d.3d, and writes each image to a GRASS 
# raster file upon each termination of the CELL monitor. 
# Each raster file is written to stdout as a 24-bit color 
# PPM file with Bill Brown's r.out.ppm module, may be piped 
# to ppmquant for color reduction if desired, 
# then piped to ppmtogif for conversion to gif format.
#
# You must set the size of the CELL monitor (and final
# images) before starting your GRASS session and running
# your modification of this script, e.g.:
#       setenv GRASS_WIDTH 401
#       setenv GRASS_HEIGHT 201 
# (will create 200 row x 400 col raster files and images)
###########################################################

# SCRIPT FOR SPEARFISH SATELLITE FLY-OVER 

export GRASS_WIDTH=601
export GRASS_HEIGHT=301

# starting view point: (get coordinates with d.what.rast)
x=606810      # east
y=4947890     # north
z=10000       # height

# center of view:
cx=599000     # east
cy=4914000    # north

#Max number of Calculations:
MAX=20

# Start calculation:
i=1
while [ $i != $MAX ]
do
  d.mon start=CELL
  echo "Calculating image $i..."
  g.region rast=$1
  d.erase
  d.3d map=$1 elev=$2 \
    from=$x,$y,$z to=$cx,$cy,2500 \
    exag=3 lines=0 field=40
#with closing driver write the Dcell-file:
  d.mon stop=CELL
  sleep 1   # wait for the CELL-driver

# GIF export:
 #  g.region rast=D_cell
 # r.out.ppm i=D_cell o=- | ppmquant 256| ppmtogif > fly_$i.gif
 # g.remove D_cell
 # echo "Generated fly_$i.gif."

# MPEG export (see also last line):
  g.rename D_cell,fly_$i
  echo "Generated fly_$i"

##------------------------
# shift position:
 # eye position:
  x=`expr $x - 1000`   # go west
#  y=`expr $y + 6200`
####  z=`expr $z + 200`

 # center of view
#  cx=`expr $cx + 400`
#  cy=`expr $cy + 1367`
  i=`expr $i + 1`
done

# MPEG output
GMPEG_SIZE=500
g.region rast=fly_1
# (wildcards are allowed):
r.out.mpeg view1="fly_?","fly_??","fly_???" output=fly3d.mpg

#remove the raster files:
i=1
while [ $i != $MAX ]
do
  g.remove rast=fly_$i
  i=`expr $i + 1`
done