13.01.2021, 17:07
Christian,
There a lot of DEM file formats.
So, I think the better (minus work) will be BIL (band interveaved by line).
The HGT format is a BIL format. In HGT, data are in Integer 16, and stand for square tiles 1°x1°, 3061 data per rows.
For the purpose of better accuracy DEM file, I will suggest BIL/HDR/PRJ format (also called ESRI HDR labelled, or ESRI BILL format), :
The .PRJ file is an ASCII file for projection, like that :
This file is mandatory if you want to accept different type of projection. But if you want, for example, only WGS84, it is enough to say "it is WGS84" (HGT files are WGS84, it's conventional).
The .HDR file is an ASCII file for description of the BIL file, like that :
In this example, the PRJ and HDR are files after converting an two HGT files into one BIL format.
The .BIL file is like in .HGT. In HGT, pixel type is INT16, in BIL, it can be other types, FLOAT 32 in this example.
So, I can give you files for testing, but say to me if you prefer any projection (WGS84, or Lambert 93, or...), or only WGS84.
Do you prefer square tiles, or any rectangular size ? Do you prefer Interger16 data or is it possible to use Float type ? (I think float is better for accuracy).
After your reply, I will generate files for you, for testing.
Best regards,
Bernard
There a lot of DEM file formats.
So, I think the better (minus work) will be BIL (band interveaved by line).
The HGT format is a BIL format. In HGT, data are in Integer 16, and stand for square tiles 1°x1°, 3061 data per rows.
For the purpose of better accuracy DEM file, I will suggest BIL/HDR/PRJ format (also called ESRI HDR labelled, or ESRI BILL format), :
The .PRJ file is an ASCII file for projection, like that :
Code:
GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]This file is mandatory if you want to accept different type of projection. But if you want, for example, only WGS84, it is enough to say "it is WGS84" (HGT files are WGS84, it's conventional).
The .HDR file is an ASCII file for description of the BIL file, like that :
Code:
BYTEORDER I
LAYOUT BIL
NROWS 3601
NCOLS 7201
NBANDS 1
NBITS 32
BANDROWBYTES 28804
TOTALROWBYTES 28804
PIXELTYPE FLOAT
ULXMAP -4.0000000001111
ULYMAP 48.0000000001111
XDIM 0.000277777777808638
YDIM 0.000277777777839488In this example, the PRJ and HDR are files after converting an two HGT files into one BIL format.
The .BIL file is like in .HGT. In HGT, pixel type is INT16, in BIL, it can be other types, FLOAT 32 in this example.
So, I can give you files for testing, but say to me if you prefer any projection (WGS84, or Lambert 93, or...), or only WGS84.
Do you prefer square tiles, or any rectangular size ? Do you prefer Interger16 data or is it possible to use Float type ? (I think float is better for accuracy).
After your reply, I will generate files for you, for testing.
Best regards,
Bernard