1) The document discusses using open source software like GDAL, GRASS, Octave, and R to process and analyze digital elevation models and GPS data from the Himalayas. 2) It provides steps to convert HDF DEM files to GeoTIFF using GDAL, incorporate GPS data into DEMs using GRASS, and analyze changes in DEMs over time between 1992-2008 using Octave and R. 3) It also describes using GMT to create publication-quality graphics from the results.

1. FOSS4G (GRASS R GMT)
Takayuki NUIMURA
11th Dec. 2011
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 1 / 15

2. Outline
1
2
Step 1: GDAL DEM
Step 2: GRASS GPS DEM
Step 3: Octave RS-DEM
Step 4: R RS-DEMs
3
R ( )
GMT ( )
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 2 / 15

3. FOSS4G FLOSS1
FLOSS
FOSS4G
データ処理&図化
(GDAL, GRASS, R, Octave)
空間データ図化
(GMT)
グラフィック処理
(Inkscape, GIMP)
プレゼンテーション
(LaTeX Beamer) Beamer
1
Free/Libre and Open Source Software
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 3 / 15

4. (ex. AX010 )
=⇒
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 4 / 15

5. N
Everest
28˚00'
[m]
30˚ China 8000
7000
Ne 27˚50'
pa Khumbu Himal 6000
l 5000
4000
Kathmandu 3000
27˚40'
2000
1000
25˚ India 0 10 km
27˚30'
80˚ 90˚ 86˚30' 86˚40' 86˚50' 87˚00'
85˚
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 5 / 15

6. 2007 ( )
N
28˚00'
Everest DEM
[ m a.s.l ] GPS
6000
( 3800 – 5500 m a.s.l.)
5000
4000
27˚50' Base station
Peak China
(Nuimura et al., J. Glaciol., in revise)
Ne
p
3000
al
km
0 5 10 India
86˚30' 86˚40' 86˚50' 87˚00'
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 6 / 15

7. 1 GDAL DEM HDF=⇒GeoTIFF
2 GRASS GPS =⇒GeoTIFF
3 Octave RS-DEMs (1992–2008) GPS-DEM
4 R RS-DEMs (m a−1 :
1992–2008)
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 7 / 15

8. Step 1: GDAL DEM
GDAL HDF2 =⇒GeoTIFF
gdal_translate (sds )
# EHdr ( )
gdal_translate -sds -of “EHdr” HDF Ehdr
# GeoTIFF
gdal_translate -of “Gtiff” Ehdr GeoTIFF
gdal_translate
( )
2
ERSDAC ASTER HDF
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 8 / 15

9. Step 2: GRASS GPS DEM
GRASS GIS v.surf.rst
1 v.in.ogr GRASS
2 v.surf.rst =⇒
3 r.out.gdal GRASS GeoTIFF
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 9 / 15

10. Step 3: Octave RS-DEM
Octave RS-DEMs GPS-DEM
Step 1:
Step 2:
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 10 / 15

11. Step 4: R RS-DEMs
R rgdal
rgdal GIS
readOGR
readGDAL
writeOGR
writeGDAL
readGDAL GeoTIFF DEM
writeGDAL GeoTIFF
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 11 / 15

12. Step 4: R RS-DEMs
1992–2008 DEM
( )
=⇒
( or )
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 12 / 15

13. Step 4: R RS-DEMs
1 readGDAL 1992–2008 DEM R
2 lm lm (m a−1 )
3 writeGDAL GeoTIFF
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 13 / 15

14. R ( )
DEM
7000
6500
6000
Elevation (m)
5500
5000
4500
Debris−free Debris−free
a) b)
4000
Debris−covered Debris−covered
−3 −2 −1 0 1 2 3 0 5 10 15 20
Elevation change (m a−1) Area (km2)
50 m (m a−1 )
R plotCI
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 14 / 15

15. GMT ( )
GDAL GeoTIFF=⇒NetCDF3 GMT
4
grdmath NoDATA
3
GMT
4
Takayuki NUIMURA ( ) FOSS4G 11th Dec. 2011 15 / 15