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Introduction to GPS and Geodesy
GEOM5002
Assignment 5
Transformations
Due Date November 15, 2014
Venessa Bennett
W0279429
SECTION
1.
Provide s
STEP 1: C
Minutes,
N A: BLUE
Stat2
Use Blue MarNAD27, to g
creen capture
Choose appro
Seconds
MARBLE
tion Latitude27004 44° 53
rble Softwaregeodetic coor
es of your resdecimal p
44
priate input a
e (dd mm ss)3’ 09.375910
e, found in thdinates in NA
sults. Supply aplaces and hei
BLUE MA
4o 53’ 09.335
and output co
) Longitude 0” N 65° 10’
he labs, and trAD83 Original
answers in deights to the n
ARBLE Answe
1” ‐65o 10’ 0
oordinate sys
(dd mm ss) 09.27654” W
ransform the l. Use method
egrees minutnearest millim
er: DMS
6.6666” h =
stems and ent
Ellipsoid ht W 29.524 m
point listed ads discussed i
es and seconmetre. (1)
29.524 m
ter input Coo
(h)
above, given in class. (1)
ds, with seco
ordinates in D
in
onds to 5
egrees,
STEP 2: Id
STEP 3: C
dentify appro
Confirm param
opriate transfo
meters of eac
ormation me
h transforma
thod (NAD27
ation step
7 – WGS84_3 & NAD83 to WGS84_1)
STEP 4: C
Calculate Final Transformattion
SECTION
2. UseMarbl
Screen Gr
N B: ARCG
Use ArcGIS
Report yosecond
St
e ArcGIS and e. To confirm
found
rabs – PDF wi
GIS
S tools to com
ur answers inds. Use the fo
tation Latitud
27004 44° 5
transform thm the correct d at C:\Progra
44
ith relevant t
mplete the re
n degrees minollowing direc
de (dd mm ss
53’ 09.37591
he position oftransformatiam Files(x86)
ArcG
4o 53’ 09.335
44.8859
transformatio
quired transf
nutes and secctions to com
s) Longitude (
0” N 65° 10’ 0
f 27004 to NAion is selecte)\ArcGIS\Des
GIS Answer: D
1” ‐65o 10’ 0
DD 2641 ‐65
ons highlighte
formations on
conds with fomplete the tra
(dd mm ss) E
09.27654” W
AD83 using thd, use the gesktop10.2\Do
DMS
6.6666” h =
5.16851851
ed
n the followin
our places pasnsformation
llipsoid ht (h)
W 29.524 m
he same meteographic_traocumentation
29.524 m
ng station, 27
st the decimain ArcGIS. (3)
)
thod used in ansformationn. (1)
7004.
l for )
Blue ns.pdf
Screen Gr
rabs – Arc Me
enus, transfo
ormation sele
A44o 53’
A 44.8859
ections and re
ANSWER DMS09.3351” ‐65
ANSWER DD2641 ‐65
esults table w
S 5o 10’ 06.666
5.16851851
with new X,Y
6”
3. Again use ArcGIS and
Arc
d transform th
cGIS ANSWER44o 53’ 09.6
A44.88601
he same statimethod. (1)
R converted t6479” ‐65o 10
ANSWER DD1331o ‐65.168
ion 27004 to
to DMS (4 d.p0’ 07.1325”
864793o
NAD83 using
p)
g the Ntv2
4.u
. Confirm youutility at http
ur results fromp://webapp.g
m ArcGIS for geod.nrcan.gc
capture
De
the NTV2 mec.ca/geod/toe of your resu
ecimal Degree
ethod for staools‐outils/ntults. (1)
es
ation 27004 utv2.php. Prov
using the ntv2vide a screen
2
ArcGIS A44o 53’ 09.6
ANSWER DMS6479” ‐65o 10
S (4 d.p) 0’ 07.1325”
5. What type of transformation method does NTv2 use? (1)
Ntv2 represents a two dimensional grid shift transformation method. It is a standard binary grid shift (.GSB) file format and can transform between NAD27 and NAD83. The grid shift method does not transform heights. Grid shifts account for local distortion and provide solutions in dX, dy and dz Source: http://www.nrcan.gc.ca/earth‐sciences/geomatics/geodetic‐reference‐systems/tools‐applications/9074 6. Explain which method of transformation is the most accurate in Nova Scotia to transform NAD27 ‐‐‐> NAD83. Use discussions in class along with the geographic_transformations.pdf to support your explanation. Transformation 1: Two‐step transformation of NAD27 (non‐geocentric) through WGS 84(geocentric) into NAD83 Original (geocentric). Represents a 3 parameter geocentric translation that assumes co‐ordinate systems are aligned (in this case WGS84 and NAD83 original) Transformation 2: NAD27 to NAD83 Original using NTv2 (Grid Shift). The Ntv2 grid shift is a direct transformation between the two datums, NAD27 and NAD83 (original) without conversion to WGS84. It uses known co‐ordinates in both datums to determine conversion values and is best applied where both datums have distortion. In this example the NAD27 to NAD83 original using NTv2 is considered more accurate because it does not convert to WGS84, removing a source of potential error and is more appropriate for transformation between distorted networks. NAD27 and NAD83 original are both distorted networks.
7
7. Transform tto NAD83
the 27004 to 3 and the NAD
NAD83 CSRSD_1983_To_N
NA
ArcGIS A44o 53’ 09.6
S from NAD27NAD_1983_CAD83 CSRS. (1
ANSWER DMS6479” ‐65o 10
7 using the NCSRS_4 to go 1)
S (4 d.p) 0’ 07.1325”
NTv2 method between NA
from NAD27AD83 and
7
8. U
Q3 ‐ TranGrid shift Q7 ‐ TranGrid shift The result(see screeNAD83 or The secongeocentri
The dx, dyNAD83CSresulting i
Use the geogr
sformation 1
sformation 2+ 3 paramete
ts of these twen grabs abovriginal using N
nd step to in Qc transforma
y, dz values aRS are assumin identical va
raphic_transffrom questio
1: NAD27 ‐‐‐>
2: NAD27 ‐‐‐> er geocentric
wo transformave). The initiaNTv2 grid shif
Q7 to converttion (see belo
re all zero, inmed identical ialues for both
ormations.pdon 3 and that
NAD83Origin
NAD83Origintransformati
ations carriedal step in bothft method.
t from NAD83ow)
dicating that in 3D space. Ch Q3 and Q7.
df to help expt from questi
nal (NTv2)
nal(NTv2) ‐‐‐>ion.
d out on pointh transformat
3 original to N
for this versiConsequently
plain the tranon 6 in NAD8
> NAD83 CSRS
t 27004 resultions are the
NAD83CSRS_4
on of NAD83y no further t
nsformed pos83 CSRS. (1)
S
t in the samesame and inv
4 represents
CSRS, NAD83ransformatio
sition in NAD
e coordinate vvolve NAD27
a 3 paramete
3original and on in perform
D83
values ‐‐‐>
er
ed,
9. Read the document “Evolution of NAD83 in Canada,” found at ftp://ftp.geod.nrcan.gc.ca/pub/GSD/craymer/pubs/nad83_geomatica2006.pdf, and explain why it is acceptable to transform from NAD27 to NAD83 CSRS using the method used in
question 7. (1) The transformation method in Q7 involves: NAD27 ‐‐‐> NAD83Original (NTv2) ‐‐‐>NAD83CSRS This is a valid transformation method because: i) NAD83(Original) and NAD83(CSRS) do not represent different reference systems. NAD83(CSRS)
represents the more accurate, updated network of the NAD83 Datum and is consistent with NAD83(Original) (Craymer, 2006).
ii) This transformation is applicable for NAD83(CSRS) because the differences between the original and CSRS versions of NAD83 are insignificant compared to low accuracy NAD27‐NAD83(Original) transformation (Craymer, 2006). These minor differences can therefore be safely ignored without introducing any systematic bias in the results.
Source: Craymer, M.R. 2006. The Evolution of NAD83 in Canada. Geomatica, Vol. 60, No. 2, p151‐164
1
10. Transformm the NAD83
D
CSRS coordin
DMS A 44o 53’ 09.5
DD convert to 44o 53’ 09.5
nate to ATS77
ANSWER Arc5415” ‐65o 10
o DMS ANSW5415” ‐65o 10
7 using the N
cGIS : 0’ 07.2591”
WER ArcGIS : 0’ 07.2591”
NS778301.gsb
b method. (1)
11. Confirwebsite hyour resu
rm your resuhttp://www.nults. (1)
lts by using tnovascotia.ca
he Coordinata/geonova/h
DMS A 44o 53’ 09.5
te Transformaome/default
ANSWER Arc5415” ‐65o 10
ation utility ot.asp. Provide
cGIS : 0’ 07.2591”
on the GeoNoe a screen gra
ova Portal ab of
Now ad
Below is a
dd the COGS s
St
screen grab of
station to you
tation LatitudCOGS 44°
f the two point
ur NAD83 CSg
de (dd mm ss53’ 06.26412
ts COGS and 27provid
RS feature clagiven below:
s) Longitude (2” N 65° 10’ 0
7004 as they ped in assignme
ass. The posi
(dd mm ss) E4.97655” W 1
plot in NAD83Cent 4)
ition of the C
llipsoid ht (h)15.799 m
CSRS using the
OGS base sta
)
base photo (C
ation is
OGS2007
12. Us
a.tr
sing ArcGIS, t
. Use the NADransformatio
transform the
D83 CSRS coon, you are re
44o 53
44o
e NAD83 CSRdone in
ordinates youquired to cre
Answer: ArcG
3’ 06.3011” ‐6
Answer: ArcG
53’ 09.6849”
RS coordinaten question be
u have obtaineate your own
GIS COGS ITRF
65o 10’ 04.98
GIS 27004 ITRF
” ‐65o 10’ 07.1
es for points 2elow).
ned in ArcGISn transforma
F 2008 DMS
807” h = 29.52
F 2008 DMS
1367” h =15.7
27004 and CO
S. To completation. (1)
24 m
799
OGS to ITRF08
te the
8 (as
bre
. Provide a scequired to cre
creen grab ofeate the cust
f this transfortom transform
rmation. The mation can b
transformate obtained fr
tion parameterom class not
ers tes. (1)
13. Co
http:0
onfirm your rCSRS to IT
com://webapp.ge01, for NAD83
results in theTRF08 using Tmputers (The eod.nrcan.gc3 CSRS and 2
e question abTRX Coordinatsoftware canc.ca/geod/too011,01,01 fo
Answer: ArcG
44o 53’ 06.3
ove by transfte Transformn also be locaols‐outils/trxr ITRF08. Pro
GIS COGS ITRF
3011” ‐65o 10
forming the Cmation Prograated on the Nx.php). Use a ovide a screen
F 2008 DMS
0’ 04.9807”
COGS stationam, located oNRCAN websireference epn grab of you
n, given in NAon the lab te, poch of 1997,ur results. (1)
AD83
01,