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nakijun / tilers-tools

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Need more datums #12

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
I am in need of a few more datums, principally SAD69 (South American Datum 
1969), COABR (Corrego Alegre) and SIRGAS2000. I have tried to add these 
manually to data_bsb.csv, but that breaks the code. For this reason I haven't 
completed my search for settings either. Also, the format of the CSV file is 
not completely clear to me

Original issue reported on code.google.com by gay.to...@gmail.com on 1 Apr 2014 at 4:24

GoogleCodeExporter commented 9 years ago 
No problem, could you please post these datum definitions or give me a link?

Original comment by vadp.d...@gmail.com on 2 Apr 2014 at 6:48

GoogleCodeExporter commented 9 years ago 
Actually a few samples would help as well

Original comment by vadp.d...@gmail.com on 2 Apr 2014 at 8:59

GoogleCodeExporter commented 9 years ago 
Corrego Alegre:
http://georepository.com/datum_1074/Corrego-Alegre-1961.html
http://georepository.com/datum_6225/Corrego-Alegre-1970-72.html
SAD
http://georepository.com/datum_6618/South-American-Datum-1969.html
SIRGAS2000
http://georepository.com/crs_4674/SIRGAS-2000.html

Samples can be downloaded from 
http://www.mar.mil.br/dhn/chm/cartas/download/cartasbsb/cartasl_eletronicas_Inte
rnet.htm (most files are WGS84 though)

Original comment by gay.to...@gmail.com on 2 Apr 2014 at 11:22

GoogleCodeExporter commented 9 years ago 
Unfortunately for the link:  
http://www.mar.mil.br/dhn/chm/cartas/download/cartasbsb/cartasl_eletronicas_Inte
rnet.htm 

I'm getting:
"A página requisitada 
"/dhn/chm/cartas/download/cartasbsb/cartasl_eletronicas_Internet.htm" não 
pôde ser encontrada."

It would be great if you'd post some links to specific files. At least one 
sample per each datum.

Original comment by vadp.d...@gmail.com on 3 Apr 2014 at 8:34

GoogleCodeExporter commented 9 years ago 
I discovered the same list night as well, seems like the site is in 
reconstruction.

Since I have no idea if any links will work at the moment I have attached a 
file in Corrego Alegre projection, I have round 2000 KAP files, so looking 
through all for different formats are very time consuming. If I come across 
other formats I'll post them here

Original comment by gay.to...@gmail.com on 3 Apr 2014 at 11:25

Attachments:

GoogleCodeExporter commented 9 years ago 
And another

Original comment by gay.to...@gmail.com on 3 Apr 2014 at 2:14

Attachments:

GoogleCodeExporter commented 9 years ago 
OK for COA datum the definition should be:

datum,COA,"+ellps=intl +towgs84=-206,172,-6,0,0,0,0"

I'll update data_bsb.csv accordingly.

Could you please send me some samples for other datums? 

BTW You could use map2gdal.py <file> to see file's datum and projection. It 
leaves .vrt file then which you can delete safely.

Original comment by ssvadim@gmail.com on 3 Apr 2014 at 4:05

GoogleCodeExporter commented 9 years ago 
Seems like COABR is an alias for COA, I saw them both in the list when I did:

for i in `find . | grep KAP`; do head -n 15 $i | grep KPN; done | less

I have some files with a mysterious ASTRONOMICAL DATUM, and one UNKNOWN, seems 
like I have no files with SIRGAS or SAD at the moment - apart from that all 
files are NAD and WGS84

Original comment by gay.to...@gmail.com on 3 Apr 2014 at 6:48

GoogleCodeExporter commented 9 years ago 
Thanks for you "find" script. Here is my modification:

IFS=$'\n' sh -c 'for i in `find . -iname \*KAP|sort`; do head -n 15 "$i" | echo 
"$i:" `grep KNP|grep -v WGS`; done'

I wonder if you'd post your "ASTRONOMICAL DATUM" sample.

Original comment by ssvadim@gmail.com on 6 Apr 2014 at 12:23

GoogleCodeExporter commented 9 years ago 
See attached

Original comment by gay.to...@gmail.com on 6 Apr 2014 at 12:35

Attachments:

GoogleCodeExporter commented 9 years ago 
As this chart covers Tern Island, then my guess is that that datum is 
equivalent to:

ASTRO TERN Island (FRIG) 1961 
(http://earth-info.nga.mil/GandG/coordsys/onlinedatum/CountryPacificTable.html#T
RN)

So the definition should look like:

datum, ASTRONOMIC DATUMS (GENERAL), "+towgs84=114,-116,-333,0,0,0,0 
+ellps=intl",

Original comment by ssvadim@gmail.com on 6 Apr 2014 at 3:20

GoogleCodeExporter commented 9 years ago 
As per a note at the chart 19016_1.KAP and some other similar ones from the 
same source I can conclude that the main features there "can be considered 
equivalent to <...> WGS 84".

More the KAP file does not contain easting/northing data (DTM).

So, there is no sense in including "ASTRONOMIC DATUMS (GENERAL)" into 
data_bsb.csv as a chart with such a datum will be converted to WGS 84 by 
default.

Original comment by ssvadim@gmail.com on 7 Apr 2014 at 1:54

GoogleCodeExporter commented 9 years ago 
BTW an useful note from http://www.thsoa.org/pdf/cgs_afe_12.pdf:

"Independent Astronomic Datums

Besides the <...> principal datums <...> there are a
number of independent astronomic datums that were established to
control small detached surveys on offlying islands or other remote
places. Among these may be mentioned several small harbors in the
Aleutian Islands, Nushagak Bay, Cape Newenham to north of the Kus-
kokwim River, Norton Sound, Port Clarence and the Pribilof Islands.
Names are not usually appended to such datums but they are referred
to as "Independent astronomic datums."

Original comment by ssvadim@gmail.com on 7 Apr 2014 at 1:57

GoogleCodeExporter commented 9 years ago 
Fixed in 95c344b8fdb0

Original comment by vadp.d...@gmail.com on 7 Apr 2014 at 2:35