S-JTSK South West EPSG:5513 upside down transformation

drone10 · August 21, 2023, 11:59am

I am using RTK drone and also GCPs.

If I just change the extension from .txt to .prj, I just create txt file with .prj in the end, but its okay if I modify .prj file in notepad and then insert text from .txt file.

Unfortunately 5228 is different and Pix4D cannot read this file.

If you open this file, you can see difference:
5228.prj (517 Bytes)

Daniele_Lecci · August 21, 2023, 1:23pm

Please note that you can only use a projected reference coordinate system as an output reference coordinate system in PIX4Dmapper.

drone10 · August 21, 2023, 2:57pm

Oh, okay… so there is no possibility to use EPSG 5228 in PIX4D mapper?

Daniele_Lecci · August 21, 2023, 3:15pm

Not as GCP or Output coordinate reference system.

drone10 · August 21, 2023, 4:01pm

I think I understand that. Unfortunately, it’s quite complicated here in terms of coordinate systems, and I’m also quite new to this field.

Can you just please explain to me how you got the file 5513.prj above?
If I download the files highlighted in this image and make them .prj, they don’t work and they don’t work because the text in them is completely different from the one you sent me.

Here is yours:
5513.prj (778 Bytes)

Here is from the site:
5513.prj (1.7 KB)

I would just like to find at least one coordinate system that is compatible with our equipment and works correctly in Pix4D… I’ve just tried 5515 which is projected, but unfortunately doesn’t work - same problem.

Daniele_Lecci · August 23, 2023, 9:28am

Hi @drone10,

In the end I used another way to get the prj using PIX4Dmapper’s log file.

Open the .p4d file using a text editor
Find the <WKT> string for the <output> coordinate system
Copy the content of the <WKT> string:

PROJCS["S-JTSK / Krovak",
GEOGCS["S-JTSK",
DATUM["System_of_the_Unified_Trigonometrical_Cadastral_Network",
SPHEROID["Bessel 1841",6377397.155,299.1528128,
AUTHORITY["EPSG","7004"]],
TOWGS84[589,76,480,0,0,0,0],
AUTHORITY["EPSG","6156"]],
PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],
UNIT["degree",0.0174532925199433,
AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4156"]],
PROJECTION["Krovak"],
PARAMETER["latitude_of_center",49.5],
PARAMETER["longitude_of_center",24.8333333333333],
PARAMETER["azimuth",30.2881397527778],
PARAMETER["pseudo_standard_parallel_1",78.5],
PARAMETER["scale_factor",0.9999],
PARAMETER["false_easting",0],
PARAMETER["false_northing",0],
UNIT["metre",1,AUTHORITY["EPSG","9001"]],				 
AXIS["Southing",SOUTH],
AXIS["Westing",WEST],
AUTHORITY["EPSG","5513"]]

into a new text file and then change

AXIS["Southing",SOUTH],
AXIS["Westing",WEST],

into

AXIS["Westing",WEST],
AXIS["Southing",SOUTH],

Save the file with .prj string

I hope this helps.

drone10 · September 20, 2023, 11:21am

Hello,
I’m writing again after some trial and errors.

If I try the method described above, I get the following error:

I am trying to create a .prj file for EPSG:5515 which is projected.
The format should be correct, but it still throws this error and the coordinates show it incorrectly after the transformation.

Here is the file:
5515.prj (886 Bytes)

And here is the format:

PROJCS[“S-JTSK/05 / Modified Krovak”,
GEOGCS[“S-JTSK/05”,
DATUM[“System_of_the_Unified_Trigonometrical_Cadastral_Network_05”,
SPHEROID[“Bessel 1841”,6377397.155,299.1528128,
AUTHORITY[“EPSG”,“7004”]],
AUTHORITY[“EPSG”,“1052”]],
TOWGS84[589,76,480,0,0,0,0],
PRIMEM[“Greenwich”,0,
AUTHORITY[“EPSG”,“8901”]],
UNIT[“degree”,0.0174532925199433,
AUTHORITY[“EPSG”,“9122”]],
AUTHORITY[“EPSG”,“5228”]],
PROJECTION[“Krovak_Modified”],
PARAMETER[“Latitude of projection centre”,49.5],
PARAMETER[“Longitude of origin”,24.8333333333333],
PARAMETER[“Co-latitude of cone axis”,30.2881397222222],
PARAMETER[“Latitude of pseudo standard parallel”,78.5],
PARAMETER[“Scale factor on pseudo standard parallel”,0.9999],
PARAMETER[“False easting”,5000000],
PARAMETER[“False northing”,5000000],
UNIT[“metre”,1,
AUTHORITY[“EPSG”,“9001”]],
AXIS[“Westing”,WEST],
AXIS[“Southing”,SOUTH],
AUTHORITY[“EPSG”,“5515”]]

Can you please help me with the solution?

Daniele_Lecci · September 25, 2023, 2:19pm

Hi,

Please note that what you see is a warning and not an error.
You can find additional information here:

Click OK . If the software can recognize the coordinate system, it will appear in the next pop up window Edit coordinate system.
Verify that the right new coordinate system appears in the pop up window Edit coordinate system.
In the main window, verify that the points representing the images are located correctly in the place where they are supposed to be located.

Let me know how it goes.