SRTM data: details and import with Arcinfo Workstation

Some information about SRTM mission and data, its structure and import with Arcinfo Workstation

• SRTM
• GRID
• Arcinfo Workstation

SRTM

Shuttle radar topographic mission (SRTM) - , (>60), (>54), , 11 2000 . SIR-C X-SAR, 12 ( ).

SRTM
(Land 0-1-2-3-4, Water 0-1-2-3-4 - )

(radar interferometry) , . .

: (unfinished, 1) (finished, 2). , , .

Version 2 - ftp://e0srp01u.ecs.nasa.gov/srtm/version2/
Version 1 - ftp://e0srp01u.ecs.nasa.gov/srtm/version1/

Level-2 - 30 (1 ), , Level-1 90 (3 ) , , . ( 50.000 2) , .

, (raw data) Level-2 .

(Interferometric Terrain Height Data (ITHD)-2). , 3030, <=20 .

11 , 3 12011201 (). .

16 ( ), , -32768, no data ( ). - - WGS84.

.

:
n45e136 /45 . .., 136 ..

(SRTM Water Body Data), 3-D Shapefile (- - ).

, , National Geospatial-Intelligence Agency , SRTM (DTED® 2). , , , . ... . ... 0. Lake elevations were set to a constant value. ... , . 30-. WGS 84. - 20 (90%), - 16 (90%). :

• - BA040
• - BH080
• - BH140

GRID

1. , , 1 (. ). grid1dg, 1 , , Tilename
2. HGT BIL
3. , BIL, HDR ( ). , . : n45e136.bil n45e136.hdr
4. HDR :
   
   BYTEORDER M
   LAYOUT BIL
   NROWS 1201
   NCOLS 1201
   NBANDS 1
   NBITS 16
   BANDROWBYTES 2402
   TOTALROWBYTES 2402
   BANDGAPBYTES 0
   NODATA -32768
   ULXMAP 136
   ULYMAP 46
   XDIM 0.000833333333333
   YDIM 0.000833333333333

HDR , ULXMAP ULYMAP ( X Y ). , , , , . , ULYMAP (. HDR , ULYMAP).

SRTM , Arcview , , ULXMAP ULYMAP ( X Y) .

For example, the coordinates of the lower-left corner of tile N40W118 are 40 degrees north latitude and 118 degrees west longitude. To be more exact, these coordinates refer to the geometric center of the lower left pixel

Arcinfo Workstation, Arcview Spatial Analyst, ArcGIS ..

4. GRID. IMAGEGRID.
:

arc> imagegrid n45e136 n45e136

5. . CON GRID.
:

arc> grid
grid> n45e136 = con(n45e136 >= 32768, n45e136 - 65536, n45e136)

, (graduated color) Arcview, => 32768 , . IMAGEGRID , ( nodata) .

6. NODATA. SETNULL GRID.
:

grid> n45e136z = setnull (n45e136c <= -32768, n45e136)

, Arcinfo Workstation, , sml-, , .

* dll, ( Win98 - c:\windows\system, W2K - c:\winnt\system32)

Arcinfo Workstation

, ( , ) HGT. !process-srtm.sml, HGT .

Arcinfo Workstation, Arcinfo:

1. , HGT ( c:\work\srtm)

&workspace __

2. , HGT

&run !process-srtm.sml

GRID, .

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