[Therion] 3D model height
Benedikt Hallinger
beni at hallinger.org
Fri Feb 19 12:18:59 CET 2021
Well then i'm out of ideas, however i do not get weird results here when
invoking proj manually:
echo "647151 242509 262" | cs2cs EPSG:23700 EPSG:4326
47d31'35.376"N 19d0'34.596"E 262.000
echo "47.526453 19.009617 262" | cs2cs EPSG:4326 EPSG:23700
647151.52 242504.51 262.00
When using EPSG:23700, does the problem also occur in kmlth.3d or just
the kml?
Am 2021-02-19 12:06, schrieb Balambér Hakapesz:
> The error only occurs when using the EOV (EPSG: 23700) coordinate
> system.
>
> [3]
> Mentes a vírusoktól. www.avg.com [3]
>
> On Fri, Feb 19, 2021 at 11:59 AM Balambér Hakapesz
> <holl.balazs63 at gmail.com> wrote:
>
>> # 2021.02.08 created by TopoDroid v 5.0.79
>>
>> #source "../th/kml.th [2]"
>> source "kml.th [2]"
>>
>> layout topodroid
>> legend on
>> symbol-hide group centerline
>> symbol-show point station
>> debug station-names
>> endlayout
>>
>> export map -layout topodroid -o kml-p.pdf -proj plan
>>
>> export map -layout topodroid -o kml-s.pdf -proj extended
>>
>> # export model -fomat survex -o kmlth.3d
>>
>> export model -output kmlo.3d
>> export model -output kmlo.lox
>> export model -output kmlo.dxf
>> export model -output kmlo.kml
>>
>> # 2021.02.08 created by TopoDroid v 5.0.79
>>
>> survey kml -title "kml"
>>
>> centerline
>> #cs long-lat
>> #fix 0 19.009617 47.526453 262
>> cs EPSG:23700 #ez felel meg az EOV-nek
>> fix 0 647151 242509 262
>> date 2021.02.08
>> # declination 5.0000 degrees
>> units length meters
>> units compass clino degrees
>> data normal from to length compass clino
>> extend right
>> 0 1 10.00 180.0 -90.0
>> 1 2 10.00 0.0 0.0
>> 2 3 10.00 90.0 0.0
>> units left right up down meters
>> data dimensions station left right up down
>> endcenterline
>>
>> endsurvey
>>
>> [3]
>> Mentes a vírusoktól. www.avg.com [3]
>>
>> On Fri, Feb 19, 2021 at 11:49 AM Benedikt Hallinger
>> <beni at hallinger.org> wrote:
>>
>>> What does the survex/aven file give you, is the error there also
>>> apparent?
>>>
>>> What is your full thconfig file for generating the kml and aven
>>> .3d?
>>>
>>> Dies the problem also exists when specifying this:
>>> cs EPSG:4326
>>> fix 0 19.009617 47.526453 262
>>>
>>> Am 2021-02-19 11:25, schrieb Balambér Hakapesz:
>>>> If I were to enter the ellisoid height, the error of Proj4 would
>>> still
>>>> remain on the EOV projection.
>>>> I could work in a UTM coordinate system, but it would be much
>>> simpler
>>>> if Therion didn’t recalculate anything. (There is no height
>>> issue
>>>> between UTM and WGS84 because there is no conversion)
>>>> This error is only present in the national projections where
>>> Proj4
>>>> performs approximate calculations for the advantage of
>>> horizontal
>>>> coordinates and the disadvantage of height.
>>>>
>>>> On Fri, Feb 19, 2021 at 11:25 AM Balambér Hakapesz
>>>> <holl.balazs63 at gmail.com> wrote:
>>>>
>>>>> thconfig:
>>>>> #cs long-lat
>>>>> #fix 0 19.009617 47.526453 262
>>>>> cs EPSG:23700 # Hungarian EOV
>>>>> fix 0 647151 242509 262
>>>>>
>>>>> kml:
>>>>> <LineString><coordinates>
>>>>> 19.00961011626948,47.52649337576407,291.08568208889801
>>>>>
>>>>> 291-262 = 29 m = 44m geoid height - 15m Proj4 error
>>>>>
>>>>> [2]
>>>>> Mentes a vírusoktól. www.avg.com [1] [2]
>>>>>
>>>>> On Fri, Feb 19, 2021 at 11:06 AM Benedikt Hallinger
>>>>> <beni at hallinger.org> wrote:
>>>>>
>>>>>> Isn't EGM84 the reference ellipsoid currently used by WGS84?
>>>>>> What you get with GPS is *not* sea level, but the altitude
>>> above
>>>>>> that
>>>>>> reference geoid (which takes into account gravital anonalys).
>>>>>>
>>>>>> If you calibrate your barometric altimeter to the hieght given
>>> by
>>>>>> a
>>>>>> height coordinate of WGS84 (like read from your car's navi at
>>> the
>>>>>> parking lot, or from a map calibrated to WGS84) then you
>>> should
>>>>>> get
>>>>>> about the same altitude.
>>>>>> If you take the cave location from GPS and enter that
>>> coordinates
>>>>>> into
>>>>>> the therion dataset wirh correct "cs" marking, the conversion
>>>>>> should
>>>>>> yield the correct result.
>>>>>> If you take the altitude from a map (or an altimeter
>>> calibrated to
>>>>>> that
>>>>>> map) in another coordinate system, you have to either apply an
>>>>>> offset
>>>>>> manually, add an instrument correction factor in therion, or
>>>>>> supply the
>>>>>> correct coordinate system (which then probalby demands
>>> conversion
>>>>>> of the
>>>>>> lat/lon coordinates).
>>>>>>
>>>>>> If generating 3D surfce meshes, you also need to supply
>>> matching
>>>>>> coordinate systems data and/or specify the correct "cs"
>>> parameter.
>>>>>>
>>>>>> I think your problem comes from mixing coordinate systems in
>>>>>> respect to
>>>>>> the height model, either at data input or when using the
>>> height
>>>>>> mesh.
>>>>>>
>>>>>> Am 2021-02-19 9:49, schrieb Balambér Hakapesz:
>>>>>>> Very rarely can anyone work at ellipsoidal heights. In local
>>>>>>> coordinate systems, it only makes sense for upper geodetic
>>>>>>> calculations. Only for GPS measurements we get an ellipsoidal
>>>>>>> altitude, even there the devices can immediately calculate
>>> the
>>>>>>> altitude of the EGM96 model with an altitude above sea level
>>>>>> (with a
>>>>>>> few meters error which is not significant compared to the 15m
>>>>>> altitude
>>>>>>> error of handheld GPS).
>>>>>>> Proj4 calculates the horizontal coordinates well, but there
>>> is a
>>>>>>> serious error in the height coordinates (for special national
>>>>>>> projections
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
> (http://www.agt.bme.hu/gis/workshop4/eloadasok/proj_poszter_3d.pdf)),
>>>>>>> so it would be better if not we would count on it but leave
>>> the
>>>>>>> altitude unchanged.
>>>>>>> Could it be an option not to change the height with Therion?
>>>>>>>
>>>>>>> [2]
>>>>>>> Mentes a vírusoktól. www.avg.com [1] [1] [2]
>>>>>>>
>>>>>>> On Fri, Feb 19, 2021 at 9:18 AM Benedikt Hallinger
>>>>>>> <beni at hallinger.org> wrote:
>>>>>>>
>>>>>>>> Hi there,
>>>>>>>> if you measure the altitude with a barometric device, you do
>>>>>> not get
>>>>>>>> the
>>>>>>>> altitude above the ellipsoid. You have to account for that
>>> at
>>>>>> the
>>>>>>>> input
>>>>>>>> of your data.
>>>>>>>>
>>>>>>>> With the "cs" command you define your input data to be in a
>>>>>> specific
>>>>>>>>
>>>>>>>> coordinate system, and also your altitude has to be given in
>>>>>> that
>>>>>>>> system. If you just put the barometric altitude there (which
>>>>>> you
>>>>>>>> usually
>>>>>>>> did calibrate to a map, didn't you?) you have to transform
>>> the
>>>>>>>> altitude
>>>>>>>> manually if the reference altitude differs.
>>>>>>>>
>>>>>>>> Am 2021-02-19 8:44, schrieb Balambér Hakapesz:
>>>>>>>>> Hi!
>>>>>>>>>
>>>>>>>>> When generating 3D models, Proj4 transforms between
>>> different
>>>>>>>>> coordinate systems.
>>>>>>>>> This also transforms the ellipsoidal altitude, but the data
>>>>>> always
>>>>>>>>> refer to altitude above sea level and should not be
>>> changed.
>>>>>>>>> The finished models do not fit the topography, you have to
>>>>>> cheat
>>>>>>>> with
>>>>>>>>> the height to be good.
>>>>>>>>>
>>>>>>>>> Balázs Holl.
>>>>>>>>>
>>>>>>>>> [1]
>>>>>>>>> Mentes a vírusoktól. www.avg.com [1] [1] [1] [1]
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Links:
>>>>>>>>> ------
>>>>>>>>> [1]
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
> http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail
>>>>>>>>> _______________________________________________
>>>>>>>>> Therion mailing list
>>>>>>>>> Therion at speleo.sk
>>>>>>>>> https://mailman.speleo.sk/listinfo/therion
>>>>>>>> _______________________________________________
>>>>>>>> Therion mailing list
>>>>>>>> Therion at speleo.sk
>>>>>>>> https://mailman.speleo.sk/listinfo/therion
>>>>>>>
>>>>>>>
>>>>>>> Links:
>>>>>>> ------
>>>>>>> [1] http://www.avg.com
>>>>>>> [2]
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
> http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail
>>>>>>> _______________________________________________
>>>>>>> Therion mailing list
>>>>>>> Therion at speleo.sk
>>>>>>> https://mailman.speleo.sk/listinfo/therion
>>>>>> _______________________________________________
>>>>>> Therion mailing list
>>>>>> Therion at speleo.sk
>>>>>> https://mailman.speleo.sk/listinfo/therion
>>>>>
>>>>> [2]
>>>>> Mentes a vírusoktól. www.avg.com [1] [2]
>>>>
>>>>
>>>> Links:
>>>> ------
>>>> [1] http://www.avg.com
>>>> [2]
>>>>
>>>
>>
> http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail
>>>> _______________________________________________
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>>
>> [3]
>> Mentes a vírusoktól. www.avg.com [3]
>
>
> Links:
> ------
> [1] http://www.avg.com
> [2] http://kml.th
> [3]
> http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail
> _______________________________________________
> Therion mailing list
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