Time dataset for .ply driver

[jmkerloch]

I'm looking for a file format to create a file that will be supported by QGIS for mesh display. I need to have a format that support:

• data on vertices
• data on faces
• temporal capabilities

I checked the source code of MDAL and I created this table for comparison of MDAL supported drivers:

Driver	Description	Read mesh	Read data	Write mesh	Write data
XDMF	XDMF	:red_circle:	:green_circle:	:red_circle:	:red_circle:
XMDF	TUFLOW XMDF	:red_circle:	:green_circle:	:red_circle:	:red_circle:
ASCII_DAT	DAT	:red_circle:	:green_circle:	:red_circle:	:green_circle:
BINARY_DAT	Binary DAT	:red_circle:	:green_circle:	:red_circle:	:green_circle:
3Di	3Di Results	:green_circle:	:green_circle:	:red_circle:	:red_circle:
ESRI_TIN	Esri TIN	:green_circle:	:green_circle:	:red_circle:	:red_circle:
GRIB	GDAL Grib	:green_circle:	:green_circle:	:red_circle:	:red_circle:
NETCDF	GDAL NetCDF	:green_circle:	:green_circle:	:red_circle:	:red_circle:
HEC2D	HEC-RAS 2D	:green_circle:	:green_circle:	:red_circle:	:red_circle:
SWW	AnuGA	:green_circle:	:green_circle:	:red_circle:	:red_circle:
TUFLOWFV	TUFLOW FV	:green_circle:	:green_circle:	:red_circle:	:red_circle:
XMS_TIN	XMS Tin Mesh File	:green_circle:	:green_circle:	:red_circle:	:red_circle:
FLO2D	Flo2D	:green_circle:	:green_circle:	:red_circle:	:green_circle:
2DM	2DM Mesh File	:green_circle:	:green_circle:	:green_circle:	:red_circle:
Ugrid	UGRID	:green_circle:	:green_circle:	:green_circle:	:green_circle:
PLY	Stanford PLY Ascii	:green_circle:	:green_circle:	:green_circle:	:green_circle:
SELAFIN	Selafin File	:green_circle:	:green_circle:	:green_circle:	:green_circle:

I wanted to use driver with write support in MDAL so this limits the usable driver to:

Driver	Description	Data on vertices	Data on faces	Data on edges	Data on volumes
SELAFIN	Selafin File	:green_circle:	:red_circle:	:red_circle:	:red_circle:
PLY	Stanford PLY Ascii Mesh File	:green_circle:	:green_circle:	:green_circle:	:green_circle:
Ugrid	UGRID	:green_circle:	:green_circle:	:red_circle:	:red_circle:

I'm doing some tests with .ply file but I'm not able to display Time dataset with this driver.

Is it supported by MDAL ?

[PeterPetrik]

@runette is the maintainer of PLY format https://github.com/lutraconsulting/MDAL/blob/master/mdal/frmts/mdal_ply.cpp

[vcloarec]

UGRID should be a good candidate. I don't understand the "Read data" column. You can read data with a lot of the driver in red.

[jmkerloch]

@vcloarec It seems that I have an issue with my github clone. My master branch won't update anymore.

I created this table with an outdated code of MDAL... I will update the issue as soon as possible.

Do you confirm that UGRID support temporal capabilities ?

[vcloarec]

@jmkerloch yes.

[jmkerloch]

@vcloarec I just updated the table but I only changed UGRID, for other drivers I don't understand that they have read support from source code.

For exemple, GDAL related drivers only have Capability::ReadMesh.

https://github.com/lutraconsulting/MDAL/blob/deba23b30491c416fb4536c1d5f459d5a44b9225/mdal/frmts/mdal_gdal.cpp#L526

Is there something that I missed while reading MDAL source code ?

[vcloarec]

ReadData for the capability means the driver can only read datan no mesh frame, that is there no information about the mesh in the file. These files are related to another mesh format. Generally, 2DM format that does not store data.

[jmkerloch]

@vcloarec so If capability is Capability::ReadMesh that means that it can also read data on mesh vertices or faces ?

I didn't get this, but how should I understand the capabilities for SELAFIN Driver:

https://github.com/lutraconsulting/MDAL/blob/deba23b30491c416fb4536c1d5f459d5a44b9225/mdal/frmts/mdal_selafin.cpp#L614

Depending on the file use you don't have information about the mesh in file ?

[vcloarec]

SELAFIN is quite particular... If I remember well, you can read some data for a mesh coming from a file from another file.

[runette]

The PLY format has not concept of time datasets. Each file is one dataset.

On Mon, 29 May 2023, 10:04 Peter Petrik, @.***> wrote:

@runette https://github.com/runette is the maintainer of PLY format https://github.com/lutraconsulting/MDAL/blob/master/mdal/frmts/mdal_ply.cpp

— Reply to this email directly, view it on GitHub https://github.com/lutraconsulting/MDAL/issues/461#issuecomment-1566726438, or unsubscribe https://github.com/notifications/unsubscribe-auth/AARC2M4SOGKFHRPWCARRJ2LXIRKBXANCNFSM6AAAAAAYSODD4U . You are receiving this because you were mentioned.Message ID: @.***>

[runette]

I have always thought that table and the contents are confusing and not necessarily correct.

On Mon, 29 May 2023, 16:23 jmkerloch, @.***> wrote:

@vcloarec https://github.com/vcloarec so If capability is Capability::ReadMesh that means that it can also read data on mesh vertices or faces ?

— Reply to this email directly, view it on GitHub https://github.com/lutraconsulting/MDAL/issues/461#issuecomment-1567206701, or unsubscribe https://github.com/notifications/unsubscribe-auth/AARC2M65WW67UYMPP3KGMILXISWO3ANCNFSM6AAAAAAYSODD4U . You are receiving this because you were mentioned.Message ID: @.***>

[jmkerloch]

@vcloarec @PeterPetrik It seems that only some of the drivers have temporal capabilities because of the format implemented.

Is there any way to define which driver support temporal capabilities ?

[jmkerloch]

I'm closing this issue since it's not related to .ply driver.

I created a new issue #463 about documentation with my understanding of reading capabilities for MDAL.