Sorry for bringing this back up - I'm having problems converting tiff to .hgt. - how can I run a script that converts all geotiff (not 25m resolution but 30m) in folder /home/example/ to .hgt?
Basically I want to fill the voids in SRTM1v30 and need to convert .hgt to tiff as gdal and then get them back to hgt.

so first I simply run:


for hgtfile in *.hgt;do gdal_fillnodata.py -md 500 $hgtfile $hgtfile.tif; done 

which will voildfill all .hgt files but gdal created rubbish (at least if I feed it to phyghtmap) if I try to simply voildfill hgt and have output also as hgt. So I need to convert them back to hgt before I can hand them over to pyhghtmap.
It should work vs a folder of the whole world 60N/60S.


Best in bash if possible, but perl is also fine if I understand the steps (I downloaded the SRTM1 from earthexplorer as .hgt - or better I will have them in a couple of days, download is pretty slow even though it is only 85GB zipped...)

On 7 January 2018 at 13:25, franco_bez <franco.bez@web.de> wrote:
Frank Stinner-2 wrote
> Hi Franco,
>
> i have seen an silly error in my area. Europa is a little bit greater ;)
> Just i have "$lattop = 70". The split create 3608 tif's with 4,5 GB in 85
> min. gdal4hgt create 1171 zipped hgt's with 5,8 GB in 3 h :((
> And then i rebuild the tif's from the hgt's in 20 min. That are 4 GB.

OK

> Perhaps you have an to old gdal-version without lzw-compression? Or
> perhaps

It's the current version of gdal

> -co \"COMPRESS=LZW\" -co \"TILED=YES\" -co \"PREDICTOR=2\"
>
> should be better
>
> -co COMPRESS=LZW -co TILED=YES -co PREDICTOR=2

That did the trick :-)

Thanks a lot.

now this is the new perl script for Ubuntu
---

use strict;

my $lonleft = -24;
my $lonright = 50;
my $latbottom = 27;
my $lattop = 70;

my $srcdir = "..";

my $delta = 1 / 3600 / 2;     # half pixel

print "#!/bin/sh\n";
print "GDAL_TRANSLATE_OPT='-multi -wo NUM_THREADS=ALL_CPUS -t_srs EPSG:4326
-r near -ot Int16 -dstnodata -32768 -of GTiff -co COMPRESS=LZW -co TILED=YES
-co PREDICTOR=2 -ts 3601 3601'\n";
for (my $lat = $latbottom; $lat != $lattop; $lat++) {
    for (my $lon = $lonleft; $lon != $lonright; $lon++) {
       printf "gdalwarp \$GDAL_TRANSLATE_OPT -te %.7f %.7f %.7f %.7f
$srcdir/all.vrt %s%02d%s%03d.tif\n",
              $lon - $delta,
              $lat - $delta,
              $lon + 1 + $delta,
              $lat + 1 + $delta,
              'N',
              $lat >= 0 ? $lat : -$lat,
              $lon >= 0 ? 'E' : 'W',
              $lon >= 0 ? $lon : -$lon;
    }
}

---

Ciao,
  Franco



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