Re: [Asdf] Location information with SDF

[Christer Holmberg <[e-mail]>]

Hi Hyunjeong Lee,

>> Q1) Just to clarify, are you suggesting to modify Option 2, and use sdfLocation instead of sdfObject (per Ari's notes)?
>
> Exactly.

What are the advantages compared to using sdfProperty?

>> Q2-1) What rule/definition is that based on?
>>
>> (I assume you mean sdfThing "Humidimeter")
>
> The rule is that the sdfLocation represents the location of the parent sdfThing or sdfObject.

Ok.

What about CHILDREN? For example, if you define sdfLocation for an sdfThing, does the location apply to the children (sdfThings and/or sdfObjects)? 

(As far as I remember, SDF does not define "inheritance" of properties etc.)


>> Q2-2) Sure, but what if there is no other?
>  If nothing else, use the parent's address (which will likely have a larger range).

But, then you do assume there is inheritance of data :)

Regards,

Christer

-----Original Message-----
From:  "Christer Holmberg" <[e-mail]>
To:     "이현정" <[e-mail]>;  "Ari Keränen" <[e-mail]>;  "[e-mail]" <[e-mail]>; 
Cc:    
Sent:  2023-11-13 (월) 22:07:00 (UTC+09:00)
Subject: RE: Re: [Asdf] Location information with SDF

Hi Hyunjeong Lee,

Thank You for the reply! Please see inline.

---

Q1:

>> The Properties in sdfObject "AddressInformation" provide data (location 
>> information) that applies to the "Humidimeter" sdfThing and the "Humidity" 
>> sdfObject.
>>
>> I think that concept is not part of base SDF - Properties only apply to the 
>> sdfObject/sdfThing for which they have been defined.
>>
>> (I know there are discussions about sdfRelations, and they are also used in 
>> Option 2. However, they are only used to map the
>> location information to a dictionary - not to relate the information to 
>> other sdfThings/sdfObjects in the SDF model.)
>>
>  I suggested adopting the form of sdfLocation to indicate the position of 
> sdfThing or sdfObject.
> This means that AddressInformation in Option2 should be replaced by 
> sdfLocation.

Just to clarify, are you suggesting to modify Option 2, and use sdfLocation 
instead of sdfObject (per Ari's notes)?

>>> Exactly.

---

Q2:

>> Related to Q1, the location Properties in sdfObject "AddressInformation" 
>> apply to "Humidimeter" sdfThing. But, assume the following structure:
>>
>>
>>                                      sdfThing "WeatherStation"
>>                                                      |
>>                                                      |
>>                                       sdfThing "Humidimeter"
>>                                                       |
>>                                                       |
>>                        -----------------------------------------------------
>>                         | 
>> |
>>                     sdfObject "Humidity"                          sdfThing 
>> "Foo"
>>                     sdfObject "AddressInformation"               |
>> 
>> |
>> 
>> sdfObject "Bar"
>>
>> Does the location information also apply to "WeatherStation" sdfThing, 
>> and/or "Foo" sdfThing (and the "Bar" sdfObject)?
>
> In the structure above, the sdfObject "AddressInformation" (sdfLocation 
> "PostalAddress" in my suggestion)  applies to the sdfObject "Humidimeter."

What rule/definition is that based on?

(I assume you mean sdfThing "Humidimeter")

>>> The rule is that the sdfLocation represents the location of the parent sdfThing or sdfObject.

> Another sdfLocation "PostalAddress" can be defined if a more detailed 
> address for sdfThing "Foo" or sdfObject "Bar" is required as shown in the 
> structure below .

Sure, but what if there is no other?
  >>>  If nothing else, use the parent's address (which will likely have a larger range).


> In order to precisely depict the location of an object indoors, sdfLocation 
> "GPS & relative location" combined with a GPS and a relative location may be 
> used.

Yes. But, if you define sdfLocation somewhere, it needs to be clear what the 
scope is. Which sdfThings/sdfObjects does it apply to.
>>> Applies to the parent sdfThings or sdfObjects as in the answer above.


>
>                                      sdfThing "WeatherStation"
>                                                         |
>                                                         |
>                                      sdfThing "Humidimeter"
>                                                         |
>                                                         |
>                         ------------------------------------------------------------------------------------------------
>                         | 
> |                                                                    |
>                     sdfObject "Humidity"             sdfLocation "GPS & 
> relative location"          sdfThing "Foo"
> 
> |
>                                                                              
>                                                          ----------------------------------
> 
> |                                           |
> 
> sdfObject "Bar"       sdfLocation "GPS & relative location"
> 
> |
> 
> sdfLocation "GPS & relative location"


---

Q3:

>> Since (based on base SDF) the only technical difference between sdfThing 
>> and sdfObject is that sdfThing can contain other sdfThings and
>> sdfObjects, does option 2 allow me to define sdfThing "AddressInformation"?
>
> I think option 2 is most appropriate for expressing the location of 
> sdfThings and sdfObjects, if "AddressInformation" is changed as sdfLocation.

Ok. So, you are suggestion to modify Option 2, and use sdfLocation instead of 
sdfObject?
>>> Exactly!

---

Regards,

Christer