old projection system and transformation to GGRS87

[achillesgr]

hello,

i am located in Greece and the current progection is GGRS87 .

before the GGRS87  we had a system named HATT with the folowing info:

 maps 1/5000 based on the Bessel ellipsoid (1841)

i have many drawings with point coordinates in the old system. is there a way to transform them in the new projection?

can someone please help?

if yes, please let me know what else info is needed for the transformation.

Thanks

[MATRIX3DSURVEYS]

You will need to go to the Planning and Analysis Workspace.  Map Setup and Create a Custom Coordinate Projection for the old system.

 ( http://georepository.com/search/by-name/query//include_world/on/datum_page/4/#datum )

Open the Old drawing and assign the Old Coordinate System to it and Save.

Open a New Drawing and Assign the required Coordinate System to It. 

On the Task Pane > Map Explorer > Attach the Drawing with the old coordinate System. 

Click Current  Drawing > Coordinate System > Set Coordinate System for Source Drawing. 

Task Pane> Map Explorer>Current Query>Location All> Draw.

That should transform every thing.

Jim

Matrix3DSurveys

[achillesgr]

Jim thanks,

I will try this.i need help to setup custom projection. I visited the your link and i found three matches about "greek"

I am not sure what to do now. Can you please help?

One think that might help you is that the greece is separeted in 109 zones , each zone had one map sheet and each sheet had some numbers (φ=40.15 λ=-1.09) for example.

How do i input those in civil3d?

Another aproach:

I can find many points with  coordinates in both systems.is there a way in civil 3d  to combine that data and do any transformation?

Thanks again.

[MATRIX3DSURVEYS]

Those are Latitude and Longitude

• Bessel ellipsoid 1841 (defined by log a and ƒ😞
• a = 6,377,397.155 m
• ƒ = 1 / 299.1528153513233 (0.003342 773154 ± 0.000005)
• b = 6,356,078.963 m.

http://karanik.webpages.auth.gr/main/images/papers/journals/365-977-1-pb.pdf

http://www.asprs.org/a/resources/grids/09-98-gabon.pdf

http://www.asprs.org/a/resources/grids/12-2002-hellenic.pdf

http://earth-info.nga.mil/GandG/publications/tr8350.2/tr8350_2.html

If you have a Leica TPS or GPS 1200 instrument You can do a coordinate transform in the instrument. Then look at the parameters on the transform tab in the instrument.

Jim

[achillesgr]

Jim,

the i found the folowing info for the datum :

HGRS87 datum

HGRS87 specifies a non-geocentric datum that is tied to the coordinates of the key geodetic station at the Dionysos Satellite Observatory (DSO) northeast of Athens (38.078400°N 23.932939°E). The central pedestal (CP) at this location has by definition HGRS87 coordinates 38° 4'  33.8000" N - 23° 55'  51.0000"E, N = +7 m.

Although HGRS87 uses the GRS80 ellipsoid, the origin is shifted relative to the GRS80 geocenter, so that the ellipsoidal surface is best for Greece.[1] The specified offsets relative to WGS84 (WGS84-HGRS87) are: Δx = -199.87 m, Δy = 74.79 m, Δz = 246.62 m.

The HGRS87 datum is implemented by a first order geodetic network, which consists of approximately 30 triangulation stations throughout Greece and is maintained by the Hellenic Military Geographical Service. The initial uncertainty was estimated as 0.1 ppm (1x10−7).[2] However there are considerable tectonic movements that move parts of Greece towards different directions, causing incompatibilities between surveys taking place at different times.

please note  :

"Although HGRS87 uses the GRS80 ellipsoid, the origin is shifted relative to the GRS80 geocenter, so that the ellipsoidal surface is best for Greece.[1] The specified offsets relative to WGS84 (WGS84-HGRS87) are: Δx = -199.87 m, Δy = 74.79 m, Δz = 246.62 m. "

1)should i input this info somewhere in the c3d?

2) the (38.078400°N 23.932939°E) are the coordinates at the UTM wgs84? (google ?)  ( i input this in google earth and i foud nothing.

3)i found all the time the term ground to grid OR grid to ground.what does it means? if i measure a point at some elevation with a gps equipment , should i apply some corection to it when i pput it on a map?

the "grid" means the elipsoid surface and all the points that are measured on a ground should converted to "grid" ?

thanks. please forgive the sily questions  but it is the first time i get involved with things like that.

[MATRIX3DSURVEYS]

Found several references:

http://download.springer.com/static/pdf/541/art%253A10.1007%252Fs12518-009-0010-4.pdf?auth66=1380048...

http://arcscripts.esri.com/details.asp?dbid=15500

The data file in the ArcScript has the variables required for each 30'  map projection.  The GGRS87 projection is included in the projection library in C3D.  Switch to Planning and Analysis Workspace > Map Setup tab > Coordinate system Library

Use the Create Wizard under Coordinate systems to create a projection for each map zone. Using the Bessel ellipsoid (1841)

Expect there will be errors up to about 20 meters, the HATT projection was a Military projection and not intended for surveying.

You may have to go from HATT to LL84 then to GGRS87 if the transform crashes.

Google enter coordinates as   38.078400,23.932939  after setting Google to decimal degrees for Lat/Long   North and East are (+) positive; South and West are (-) negative.

Take a look at the Leica newsletters for information on the difference between Surface Distance and Grid Distance, ellipsoidal height and orthometric height.

http://www.leicaus.com/support/GPS1200/GPS_System1200_Newsletters.cfm

http://www.leicaus.com/support/Advantage2004/System1200Newsletters/System1200_41_Mixing%20GPS%20and%...

Jim

Surveyor / Programmer

Matrix3DSurveys

[kwtsakiskwnstantinos]

Καλησπέρα.

Θα ήθελα να ρωτήσω αν έχει περάσει κάποιος στο CIVIL 3d τους ΟΜΟΕ στο design criteria allignments!

Γιατί προσπαθώ να τους περάσω αλλά το πρόγραμμα έχει διαφορετικούς τύπους είτε για εγκάρσια τριβή κλπ!!

Ευχαριστώ εκ των προτέρων!!