TMC file coordinates format

  • Dear IPACS team,

    One read in various places that the coordinates in the TMC file must be in 0.00° format only.

    Is this a fact or an urban legend? in case it's a fact, why is this?

    0.01° represents up to more than 1km on Earth surface, which is extremely coarse for scenery placement. Considering the variable is a float64, and INF coordinates are typically in 0.0000000000° format this looks pretty odd to me.

    What are the rules for rounding up the coordinates?

    1) standard 0.5 rule?

    2) round up toward inner side of the photo?

    3) round up toward outer side of the photo?

    For instance, let's say the upper left corner LONLAT of a photo is 5.0943975000°, 46.4038750000°, should we round up:

    1) 5.09°, 46.40° (standard rounding up rule) ?

    2) 5.10°, 46.40° to ensure the corner is located inside the photo ?

    3) 5.09, 46.41° to ensure the corner is located outside the photo ?

    Thanks in advance for clarification.

    BTW I compiled sceneries with both 0.00° and 0.0000000000° format in my TMC and couldn't find any difference so far, but I was merely concentrating in coping with the stripes...

    Cheers

    Antoine

    Config : i7 6900K - 20MB currently set at 3.20GHz, Cooling Noctua NH-U14S, Motherboard ASUS Rampage V Extreme U3.1, RAM HyperX Savage Black Edition 16GB DDR4 3000 MHz, Graphic Card Gigabyte GeForce GTX 1080 8GB, Power supply Corsair RM Series 850W, Windows 10 64 bit.

  • hello Antoine,

    For my programmatic solution this is the level of precision I'm pulling out of the imagery for the TMC file. After the 8th decimal place you are running into the sub centimeter resolution and there is no practical reason to go deeper (but my software gives me up to 11 decimal points so i kept them)

    <[tmcolormap_region][element][0]

    <[uint32] [level] [11]>

    <[vector2_float64] [lonlat_min] [-105.000023181 39.6249718057]>

    <[vector2_float64] [lonlat_max] [-104.937472093 39.6875151444]>

    >

    Edited 3 times, last by Sycosys (July 19, 2017 at 4:12 PM).

    • Official Post

    Like I have said a few times now, using more than the x.xx format may cause you problems where you will run the job and find no output files. I've tested this and confirmed that this causes this; but not all of the time for some reason.

    IPACS Development Team Member

    I'm just a cook, I don't own the restaurant.
    On behalf of Torsten, Marc, and the rest of the IPACS team, we would all like to thank you for your continued support.

    Regards,

    Jeff

  • Like I have said a few times now, using more than the x.xx format may cause you problems where you will run the job and find no output files. I've tested this and confirmed that this causes this; but not all of the time for some reason.

    that's interesting. Haven't had that issue so far in over 300 converted images using up to and including 11decimal places, ill need to look into that. as Antoine mentions though only 2 decimals is not nearly enough precision to line up orthotiles..

  • I was fine with 6dps for a while, but then hit a problem . Reduced to 2dps and all ok. For a TMC of course it doesn't need to be that precise, as it isn't doing any lining up, just defining the outer area.

    • Official Post

    I was fine with 6dps for a while, but then hit a problem . Reduced to 2dps and all ok. For a TMC of course it doesn't need to be that precise, as it isn't doing any lining up, just defining the outer area.

    Indeed, so just make the perimeter larger than your image area.

    IPACS Development Team Member

    I'm just a cook, I don't own the restaurant.
    On behalf of Torsten, Marc, and the rest of the IPACS team, we would all like to thank you for your continued support.

    Regards,

    Jeff

  • that's interesting. Haven't had that issue so far in over 300 converted images using up to and including 11decimal places, ill need to look into that. as Antoine mentions though only 2 decimals is not nearly enough precision to line up orthotiles..

    Don't take any offence Jeff, but that's why I'm asking for a technical explanation for this and not just a statement...

    And if it appears we really need to round up coordinates for a good reason, then we definitely need rounding up guidance as said in my previous post, because it currently doesn't make much sense...

    Cheers

    Antoine

    Config : i7 6900K - 20MB currently set at 3.20GHz, Cooling Noctua NH-U14S, Motherboard ASUS Rampage V Extreme U3.1, RAM HyperX Savage Black Edition 16GB DDR4 3000 MHz, Graphic Card Gigabyte GeForce GTX 1080 8GB, Power supply Corsair RM Series 850W, Windows 10 64 bit.

  • Indeed, so just make the perimeter larger than your image area.

    Ok, thanks for that.

    Cheers

    Antoine

    Config : i7 6900K - 20MB currently set at 3.20GHz, Cooling Noctua NH-U14S, Motherboard ASUS Rampage V Extreme U3.1, RAM HyperX Savage Black Edition 16GB DDR4 3000 MHz, Graphic Card Gigabyte GeForce GTX 1080 8GB, Power supply Corsair RM Series 850W, Windows 10 64 bit.

    • Official Post

    The TMC coordinates only define the parameter coordinates around your project, you are reading way too much into this. Provide more information as to what you are trying to accomplish so that we can assist better.

    IPACS Development Team Member

    I'm just a cook, I don't own the restaurant.
    On behalf of Torsten, Marc, and the rest of the IPACS team, we would all like to thank you for your continued support.

    Regards,

    Jeff

  • The TMC coordinates only define the parameter coordinates around your project, you are reading way too much into this. Provide more information as to what you are trying to accomplish so that we can assist better.

    i guess it would be helpful to say that the TFW files are where the geoconvert tool derives the tile positions from.

    The tmc is a working region, defining a space in which the convert tool is working

    the tfw are the exact positions and pixel sizes which are relevant to the placement of scenery tiles

    • Official Post

    i guess it would be helpful to say that the TFW files are where the geoconvert tool derives the tile positions from.

    The tmc is a working region, defining a space in which the convert tool is working

    the tfw are the exact positions and pixel sizes which are relevant to the placement of scenery tiles

    That is correct. :)

    IPACS Development Team Member

    I'm just a cook, I don't own the restaurant.
    On behalf of Torsten, Marc, and the rest of the IPACS team, we would all like to thank you for your continued support.

    Regards,

    Jeff

  • The TMC coordinates only define the parameter coordinates around your project, you are reading way too much into this. Provide more information as to what you are trying to accomplish so that we can assist better.

    Pretty simple indeed, I try to figure out exactly how it works, not just blind recipes, and check how we can think of making sceneries in a near future.

    i guess it would be helpful to say that the TFW files are where the geoconvert tool derives the tile positions from.

    The tmc is a working region, defining a space in which the convert tool is working

    the tfw are the exact positions and pixel sizes which are relevant to the placement of scenery tiles

    Not totally exact. As now clarified by IPACS here, tile position, shape and resolution are actually derived from the AIC file only by GeoConvert.

    If there's no AIC file, GeoConvert tries to create one from the INF file.

    If there's no INF file, GeoConvert tries to create one from the TFW file.

    What really matters in the end is the AIC files associated to source images

    The TFW file is only a facultative, secondary source you can write by hand if you don't have any INF...

    Regarding the TMC file I understand now the coordinates don't need to be accurate,

    I never noticed issues yet with full coordinates in the TMC file, but it could be related to the bug causing GeoConvert to skip some image files depending on their name, this should be further investigated because it will cause unpredictable problems.

    Cheers

    Antoine

    Config : i7 6900K - 20MB currently set at 3.20GHz, Cooling Noctua NH-U14S, Motherboard ASUS Rampage V Extreme U3.1, RAM HyperX Savage Black Edition 16GB DDR4 3000 MHz, Graphic Card Gigabyte GeForce GTX 1080 8GB, Power supply Corsair RM Series 850W, Windows 10 64 bit.

  • The TFW file is only a facultative, secondary source you can write by hand if you don't have any INF...

    if you pull jp2s from the USGS they already contain all this info. Just a matter of using the right tools to create the tfw for you. I am generating mine on-the-fly as I am projecting the jp2 into a lat/long coordinate system/converting it to tif. no need to mess about with inf files when you can just build it's coordinate system from scratch

  • i guess it would be helpful to say that the TFW files are where the geoconvert tool derives the tile positions from.

    The tmc is a working region, defining a space in which the convert tool is working

    the tfw are the exact positions and pixel sizes which are relevant to the placement of scenery tiles

    This is important for me to understand.

    Do you mean that we can, for example, also choose both blue (outside) and yellow (inside) area from the same orthophoto?

    (See illustration).

  • Sycosys,

    since you are able to do so, you could even directly write the AIC code.

    Hartman,

    yes, you can specify different frames for different levels in the TMC.

    It does not matter, whether this is one or more input images.

    Rodeo

    • Official Post

    Trespassers

    What exactly are you having trouble figuring out? Maybe you are just explaining this in a way that I'm not understanding. We are just trying to help you out here.

    IPACS Development Team Member

    I'm just a cook, I don't own the restaurant.
    On behalf of Torsten, Marc, and the rest of the IPACS team, we would all like to thank you for your continued support.

    Regards,

    Jeff