Digital Elevation Models

Transcription

1 Digital Elevation Models National Elevation Dataset 14-Oct-14 GEO327G/386G, UT Austin 1

2 Data Sets US DEM series 7.5, 30, 1 o for conterminous US 7.5, 15 for Alaska US National Elevation Data (NED) GTOPO30 Global Land One-kilometer Base Elevation (GLOBE) ETOPO2 Shuttle Radar Topographic Mission (SRTM) Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) LIDAR data (TNRIS and other sources) Custom models from stereo photo pairs - photogrammetry 14-Oct-14 GEO327G/386G, UT Austin 2

3 US 1 o DEMs ~90 meter resolution WGS72 or WGS84 datum Decimal seconds (!) in older.dem format Elev. in meters Obtain via FTP 14-Oct-14 GEO327G/386G, UT Austin 3

4 NAD83 (or NAD 27) Resolution 30 (or 10) meters UTM projections Entire US available US 7.5 DEMs 1:130,00 as captured 14-Oct-14 GEO327G/386G, UT Austin 4

5 Data Sets US 7.5 DEMs: detailed view 1:50,000 as captured 14-Oct-14 GEO327G/386G, UT Austin 5

6 Data Sets US 7.5 DEMs: at 1:24,000 1:50,000 as captured 14-Oct-14 GEO327G/386G, UT Austin 6

7 US National Elevation Data (NED) Seamless data set for US and territories 1 Arc Second (30 m) resolution NAD83, decimal degrees Distribution very slick Available in Arc.grd format 14-Oct-14 GEO327G/386G, UT Austin 7

8 GTOPO30 USGS Global 30-Arc Second DEM Completed 1996 Horizontal grid spacing ~ 1 km 21,600 rows x 43,200 columns WGS84 and sea level datums Data are in decimal degrees and meters above S.L. 14-Oct-14 GEO327G/386G, UT Austin 8

9 GTOPO30 30 o x 50 o Data Tiles, EROS Data Center or via FTP 14-Oct-14 GEO327G/386G, UT Austin 9

10 GTOPO30 in ArcMap Load in band-interleaved-by-line (.bil) format Convert.bil to.grd (Spatial Analyst) -16 bit binary integer data converted to ASCII Use map calculator to restore negative values and convert 9999 (no data) cells to null. Details are available 14-Oct-14 GEO327G/386G, UT Austin 10

11 GTOPO30 tiles in ArcMap 1:10,000,000 (as captured) 100 meter classes 14-Oct-14 GEO327G/386G, UT Austin 11

12 GTOPO30 resolution: S. Africa 1:2,000,000 1:1,000, Oct-14 GEO327G/386G, UT Austin 12

13 The Global Land One-km Base Elevation G.L.O.B.E. NOAA data 14-Oct-14 GEO327G/386G, UT Austin 13

14 The Global Land One-km Base Elevation GLOBE 1 completed o x 45 o tiles WGS84, decimal degrees Import in ArcMap exactly like GTOPO30 14-Oct-14 GEO327G/386G, UT Austin 14

15 ETOPO2 NOAA global relief (land & oceans) Gridded at 2 minute resolution (~4 km): columns x 5400 rows Subsets can be extracted from CD in a variety of formats 14-Oct-14 GEO327G/386G, UT Austin 15

16 ETOPO2 14-Oct-14 GEO327G/386G, UT Austin 16

17 ETOPO2 14-Oct-14 GEO327G/386G, UT Austin 17

18 Shuttle RadarTopographic Mission 10-day mission in Feb to map earth s topography at 30 m x, y resolution and ~ 16 m in z Topography derived from radar interferometry Best global data set to date Images courtesy of NASA interferogram 14-Oct-14 GEO327G/386G, UT Austin 18

19 SRTM Coverage ~ 60 o N to 56 o S latitude ~ 80% of land surface Only uniform global elevation dataset Images courtesy of NASA 14-Oct-14 GEO327G/386G, UT Austin 19

20 SRTM Data Availability 1-arc second (30 meter) SRTM data of the continental US available via the USGS EDC Seamless Distribution System Up to 30 degree squares of raster data (1.6 gigabytes), in 100 megabyte sized files, can be downloaded at no charge. As new 3-arc second (~90 meter) international continental datasets are available, USGS will distribute via the Seamless Data Distribution System - Enhanced. Higher resolution (30 meter) international data are available via special request (?) 14-Oct-14 GEO327G/386G, UT Austin 20

21 ASTER DEMs Advanced Spaceborn Thermal Emission and Reflection Radiometer Used for surface temperature, reflectance and elevation See ASTER data site for details 30 meter resolution DEMs are available for registered users (i.e. GDEM) global data set! If not GDEM then data conversion for individual tiles to ArcInfo is required 14-Oct-14 GEO327G/386G, UT Austin 21

22 ASTER GDEM Global 30 meter postings! 14-Oct-14 GEO327G/386G, UT Austin 22

23 Single ASTER Tile Example Lascar volcano, Chile 14-Oct-14 GEO327G/386G, UT Austin 23

24 LIDAR LIght Detection And Ranging = Laser Radar : two-way ranging technique using a laser scanner Airborne LIDAR Scanning (Ground-based) LIDAR 14-Oct-14 GEO327G/386G, UT Austin 24

25 Airborne LIDAR From Gibeaut, Oct-14 GEO327G/386G, UT Austin 25

26 Airborne LIDAR Requires Precise positioning for aircraft (DGPS ground and air) Laser ranges & scan angles Platform position (yaw, pitch, roll of aircraft) Produces Swaths 100 s meters wide Accuracy of 1-4 cm in x,y,z A Laser head B Control rack BEG s (old) LIDAR unit in a Cesna Oct-14 GEO327G/386G, UT Austin 26

27 Matagorda Island LIDAR Contour interval = 25 cm! From Gibeaut, Oct-14 GEO327G/386G, UT Austin 27

28 Airborne LIDAR in ArcGIS 1. Convert LAS file(s) to Multipoint feature class 2. Use Multipoint to create a TIN Terrain 3. Covert TIN to DEM Terrain Model (TIN) hillshade of DEM (raster) 14-Oct-14 GEO327G/386G, UT Austin 28

29 Application: Airborne LIDAR slope mapping Mapping of geologic units and faults by changes in slope, e.g. central Texas hill country Slope Map hillshade of DEM (raster) Cretaceous Glen Rose and Walnut Formations (carbonate rocks) 14-Oct-14 GEO327G/386G, UT Austin 29

30 Terrestrial LIDAR Rapid, quantitative characterization of outcrops 2,000 pts/sec, mins/scan Point clouds rendered with software 14-Oct-14 GEO327G/386G, UT Austin From Belian et al.,

31 360 o Cave Image From Gary 14-Oct-14 GEO327G/386G, UT Austin 31

32 Terrestrial LIDAR Applications From Belian et al., Oct GEO327G/386G, UT Austin

33 Scanning Lidar on robotic rover 14-Oct-14 GEO327G/386G, UT Austin 33

34 Custom Photogrammetry Unmanned Aerial Vehicles (UAVs) and photogrammetry software 274 stitched UAV images Google Earth image 14-Oct-14 GEO327G/386G, UT Austin 34

35 Custom Photogrammetry SfM = Structure from Motion = photogrammetry From Fonstad et al., stitched UAV images 14-Oct-14 GEO327G/386G, UT Austin 35