358
May 2015
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
12. It’s not about the career, stupid
Finally, let’s take a step back and consider this for a
moment. We live on a small planet orbiting a star, going
round and round in circles. Sooner or later this star will
explode in a massive supernova. Whatever you believe in,
you were probably not put on this planet to file papers,
collect badges, or clock endless miles on a hamster wheel
(besides, the Earth’s orbit is doing that for you already).
So whatever you do, you should do it because you love
doing it – not because it has better career prospects in
some distant, uncertain future. Career development can
take on many shapes and forms (upwards, sideways,
deeper, broader) – and then one day the Sun will blow up
and destroy everything you ever worked for. You’ll never
regain the time wasted doing something you didn’t enjoy.
A career is basically a journey where, one day, you can
look back and say, that was fun! Nothing more.
So actually, forget everything I said. Go your own way.
Good luck!
For more information on Thierry Gregorius, visit his
personal blog, Georeferenced— A blog on all things Data,
Geo, Web. Lighthearted and occasionally off-piste, https://
georeferenced.wordpress.com/
located in the forest and on the hill to the west of the map
tack location of Google Earth™, and a short distance to the
west of the Geodesy Department building.
Helmertturm
(Helmert tower)
in Pottsdam, Germany is the
origin of the European Datum of 1950, Φ
o
= 52º 22´ 51.4456˝ N,
Λ
o
= 13º 03´ 58.9283˝ E, referenced to the International 1924
ellipsoid. The tower is located to the southwest of the map
tack, and several ground level photographs are associated
with its location.
Gellért-Hegy
is the origin of Gellért-Hegy 1874 datum
and Gellért-Hegy 1908 datum, Φ
o
= 47º 29´ 09.6380˝ N, Λ
o
= 19º 03´ 07.5533˝ E, referenced to the Bessel 1841 ellipsoid.
The citadel is located to the northwest of the map tack, and
is on the top of Gellért Hill overlooking the Danube River in
Budapest, Hungary. The citadel is large and the exact spot
used for the astronomic position is not obvious.
Quito Observatory
is the origin of the Ecuador 1928
datum, Φ
o
= 00º 12´ 47.313˝ S, Λ
o
= 78º 30´ 10.331˝W, referenced
to the International 1924 ellipsoid. Located about 30 meters
East and perhaps 150 meters South of the map tack, the
observatory appears to still have a conical corrugated metal
roof that existed back in the late 1980s in the old city park.
Madrid Observatory
is the origin of the Madrid
1853 datum, Φ
o
= 40º 24´ 29.7˝ N, Λ
o
= 03º 41´ 14.546˝ W,
referenced to the Struve 1860 ellipsoid. The map tack is on the
observatory grounds, apparently slightly to the southeast of
an observatory building, but there are numerous observatory
domes also on the site so which one is the precise dome
location is not obvious.
DCS 3 Lighthouse 1955
is the origin for St. Lucia 1955
datum, Φ
o
= 13º 42´ 35˝ N, Λ
o
= 60º 56´ 37˝ W, referenced to the
Clarke 1880 ellipsoid. The map tack is located to the South of
the lighthouse.
291 Vrcevo
is the origin for Vrcevo 1906 datum in Croatia,
Φ
o
= 49º 01´ 57.834˝ N, Λ
o
= 15º 23´ 40.224˝ E, referenced to
the Bessel 1841 ellipsoid. The map tack agrees for latitude;
the actual point on the hill top is to the west and has ground
level images of the ruins.
Observatorul Astronomic Militar Parcul Tineretului
is the origin for New Romanian 1930 datum, Φ
o
= 44º 24´
34.20˝ N, Λ
o
= 26º 06´ 44.98˝ E, referenced to the Bessel 1841
ellipsoid. The old published coordinates place the map tack
too far North, and the observatory is actually just East of the
double-span bridge in the park. A ground level image shows
the observatory. The location differs by some 12 seconds in
latitude and 7 seconds in longitude; excessive for a brick-
and-mortar observatory and likely more of an error in geo-
referencing.
Frauenkirche
(North Church Tower), Munich is the
origin for the Old Bavarian datum of Germany, Φ
o
= 48º 08´
20.000˝ N, Λ
o
= 11º 34´ 26.483˝ E, referenced to the Bessel
1841 ellipsoid. The old coordinates place the map tack at the
Eastern end of the church, latitude being apparently perfect,
longitude just perhaps 10 meters off; quite a coincidence.
The National Geospatial-Imagery Agency (NGA) publishes
a free software package called GeoTrans that allows one to
transform from geodetic coordinates to geocentric coordinates.
If one use GeoTrans to convert classical geodetic coordinates
of datum origins such as those enumerated above with the
appropriate ellipsoid and then does the same with the Google
Earth™ coordinates of the actual photo-identifiable point
using the WGS84 ellipsoid, … the difference in the geocentric
coordinates will serve as a “pretty good” approximation of the
datum shift from native datum to the WGS84 datum; at least
in the vicinity of the classical datum origin.
The contents of this column reflect the views of the author, who is
responsible for the facts and accuracy of the data presented herein.
The contents do not necessarily reflect the official views or policies of
the American Society for Photogrammetry and Remote Sensing and/
or the Louisiana State University Center for GeoInformatics (C
4
G).
Professional Insight
continued from page
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