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Hi(gh)!
On 11.05.2018 03:23, Jörg "Yadgar" Bleimann wrote:
> Hi(gh)!
>
> On 11.05.2018 01:57, Bald Eagle wrote:
>
>> https://lite.qwant.com/?q=convert+from+latitude+to+distance&client=opensearch
>>
>>
>>
https://gis.stackexchange.com/questions/91865/how-to-convert-distance-into-latitude-longitude
>>
>>
>> http://www.movable-type.co.uk/scripts/latlong.html
>>
>>
https://stackoverflow.com/questions/238260/how-to-calculate-the-bounding-box-for-a-given-lat-lng-location
>>
>
> Too complicated for my feeble brain... I just once more gave in to
> pixeling away another three, four or five years of my life, using
> OpenTopoMaps and OpenStreetMaps, which both are just classical
> Mercator's projections, which I'm able to handle mathematically!
Meanwhile, I installed the proj-bin package for Debian, a positively
ancient piece of Unix software dating back to pre-Linux days... and with
the "invproj" command line tool I'm finally able to convert UTM into
geographic coordinates!
Here is what the original data (available under
https://www.opengeodata.nrw.de/produkte/geobasis/dgm/dgm1/, I downloaded
the Cologne (Köln) data file) looked like - for convenience just a 5 by
5 slice from the original 2000 by 2000 measuring points (spaced 1 meters):
32342000.00 5658000.00 45.11
32342000.00 5658001.00 45.20
32342000.00 5658002.00 44.96
32342000.00 5658003.00 44.59
32342000.00 5658004.00 44.40
32342001.00 5658000.00 45.16
32342001.00 5658001.00 45.13
32342001.00 5658002.00 45.00
32342001.00 5658003.00 44.67
32342001.00 5658004.00 44.45
32342002.00 5658000.00 45.11
32342002.00 5658001.00 45.13
32342002.00 5658002.00 45.09
32342002.00 5658003.00 44.75
32342002.00 5658004.00 44.48
32342003.00 5658000.00 45.11
32342003.00 5658001.00 45.11
32342003.00 5658002.00 45.12
32342003.00 5658003.00 44.79
32342003.00 5658004.00 44.45
32342004.00 5658000.00 45.10
32342004.00 5658001.00 45.10
32342004.00 5658002.00 45.16
32342004.00 5658003.00 44.87
32342004.00 5658004.00 44.53
The first column contains the right (or east) value in meters, relative
to the reference meridian of Cologne's UTM zone. In UTM projection, the
Earth's surface is divided into 60 meridional zones, each one 6 degrees
wide and numbered, beginning with 180°W. Cologne's UTM zone is 32, with
9°E being the reference meridian. To avoid negative right values, the
reference meridian in any zone is given the arbitrary value of 500000
(so-called "false easting").
The second column contains the distance to the equator, i. e. the high
(or north) value; the third column is the elevation in meters above sea
level, which will pass unaltered through the following operations.
As the first column data are concatenated with the zone number (32), in
each line the first two characters have to be removed. I did this with
the powerful Unix editor tool sed:
sed -e 's/^32//g' testtile > testtile_no32
...and voilà:
342000.00 5658000.00 45.11
342000.00 5658001.00 45.20
342000.00 5658002.00 44.96
342000.00 5658003.00 44.59
342000.00 5658004.00 44.40
342001.00 5658000.00 45.16
342001.00 5658001.00 45.13
342001.00 5658002.00 45.00
342001.00 5658003.00 44.67
342001.00 5658004.00 44.45
342002.00 5658000.00 45.11
342002.00 5658001.00 45.13
342002.00 5658002.00 45.09
342002.00 5658003.00 44.75
342002.00 5658004.00 44.48
342003.00 5658000.00 45.11
342003.00 5658001.00 45.11
342003.00 5658002.00 45.12
342003.00 5658003.00 44.79
342003.00 5658004.00 44.45
342004.00 5658000.00 45.10
342004.00 5658001.00 45.10
342004.00 5658002.00 45.16
342004.00 5658003.00 44.87
342004.00 5658004.00 44.53
Now the UTM coordinates can be converted to geographic coordinates, and
as I want to have the resulting ASCII file processed by a POV-Ray
script, I prefer output in decimal form rather than degrees-minutes-seconds:
invproj +proj=utm +zone=32 -f %.9f testtile_no32 > testtile_degrees
Here we go:
6.745681594 51.051771388 45.11
6.745681158 51.051780374 45.20
6.745680721 51.051789359 44.96
6.745680285 51.051798344 44.59
6.745679848 51.051807330 44.40
6.745695850 51.051771663 45.16
6.745695414 51.051780649 45.13
6.745694977 51.051789634 45.00
6.745694541 51.051798620 44.67
6.745694104 51.051807605 44.45
6.745710106 51.051771938 45.11
6.745709670 51.051780924 45.13
6.745709233 51.051789909 45.09
6.745708797 51.051798895 44.75
6.745708360 51.051807880 44.48
6.745724362 51.051772213 45.11
6.745723926 51.051781199 45.11
6.745723489 51.051790184 45.12
6.745723053 51.051799170 44.79
6.745722616 51.051808155 44.45
6.745738618 51.051772488 45.10
6.745738182 51.051781474 45.10
6.745737745 51.051790459 45.16
6.745737309 51.051799445 44.87
6.745736872 51.051808430 44.53
Afterwards, I will use sed once more to replace the tabs and spaces by
commas, as well as adding a comma at the end of each line - and then
programming ultra-high resolution terrain reliefs with POV-Ray can
begin! I wish I had such accurate data for Afghanistan...
Watch out for the first OpenCologne terrain views in the next few weeks!
See you in Khyberspace!
Yadgar
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