Re: [Crm-sig] Issue 388 measuring position

[Hiebel, Gerald]

Dear Martin,

thanks for the feedback and pointing me to P196 relating the E18 to E92. I 
missed that one, now the Presence works fine for E18.
Looking forward the discussion,

Best,
Gerald

From: Martin Doerr 
Date: Monday, 8. March 2021 at 09:39
To: "Hiebel, Gerald" , crm-sig 
Subject: Re: [Crm-sig] Issue 388 measuring position

Dear Gerald,

Yes, this should be subclass of O21 Measurement. We need further elaboration 
about how measurements relate to the approximation of things of interest. I 
found this to be quite diverse, and adding to this class a repetition of all 
topological relations confusing. E18 still has a Presence directly related.

Best,

Martin

On 3/8/2021 10:07 AM, Hiebel, Gerald wrote:
Dear Martin and all,

thanks for taking this forward and the suggested proposition, which defines the 
process very well.

One question I have is how to relate the Position Measurement to the measured 
object (E18 or S10).
I believe the E93 Presence is the correct way for it, but we may run into a 
problem, as E18 is no longer a subclass of E92 and therefore not of E93.

For implementation simplicity a shortcut to a measured object in the form of a 
specific property would be nice, or could we use O24 measured ?
If so, should we make  Position Measurement  a subclass of O21 Measurement and 
maybe include an example that shows the modelling.

But maybe I did not see an obvious solution.
Best,
Gerald


From: Crm-sig 
<mailto:crm-sig-boun...@ics.forth.gr> on behalf 
of Martin Doerr <mailto:mar...@ics.forth.gr>
Date: Monday, 1. March 2021 at 21:31
To: crm-sig <mailto:Crm-sig@ics.forth.gr>
Subject: [Crm-sig] Issue 388 measuring position

Dear All,

I revise my previous proposal for measuring positions:



Any position measurement is based

on triangulation with multiples distances to reference points and angle 
measurements. GPS measures distances to satellites. Distances are Dimensions. 
If directed distances use georeferenced directions, i.e. angle to the rotation 
axis of earth, etc. angles

are again dimensions. Hence, a position measurement is an evaluation of a 
combination of multiple associated distance and angle measurements from a 
particular spot to certain reference points of known position in the same 
reference space. If stars are used,

they constitute (extremely) distant reference points. Gravity and Earth 
Magnetic Field also provide reference directions for angle measurements that do 
not need a second reference point. Classical longitude measurements use 
temporal simultaneity of a common

event with a reference location, which evaluates to an angle. All methods are 
fairly complex, but the details are a standard routine or even hidden in a 
modern GPS module.


Therefore

we argue that position measurement is a specific (composite) observation which 
results in a position expression, but the constituent dimensions may or may not 
be documented.

Hence,

P40 observed dimension (was observed in): E54 Dimension may not be instantiated.



All

position measurements are approximations of other places. Therefore, they 
result in a declarative place defined by an E94 Space Primitive. Since in 
general we talk about moving reference spaces, moving things and evolving 
processes, the time of measurement

is essential. We take it either to be the time-span of the measurement, or a 
narrower time-span which covers the contributing time-critical observations. In 
essence, this defines a declarative spacetime box (volume), which again is an 
approximation. It appears

to me that such an approximation would normally be used to determine parts of 
the extent of some instance of Presence by overlap, coverage or containment.


Sxxx

Position Measurement

Subclass

of:E16 Attribute Assignment

Scope

note: This class comprises activities of measuring positions in space and 
time. The measured position is intended to approximate a part or all of the 
extent of the presence (instance of E93 Presence) of an instance of E18 
Physical Thing or E4 Period of

interest, such as the outer walls of an excavated settlement, the position of a 
ship sailing or the start and end of athlete’s run in a competition. 
Characteristically, a theodolite or GPS device may be positioned on some 
persistent feature. Measuring the

position of the device will yield an approximation of the position of the 
feature of interest. Alternatively, some material item may be observed moving 
through a measured position at a given time.

A

position measurement is an evaluation of a combination of measurement of 
multiple associated distances and/or angles (instances of E54 Dimension) from a 
particular spot to certain reference points of previously known position in the 
same reference space.

Often, the observed constituting dimensions are not documented, or hidden in an 
electronic device software.The measured position is given as an E94 Space 
Primitive corresponding to a declarative place. Toge

Re: [Crm-sig] Issue 388 measuring position

[Martin Doerr]

Dear Gerald,

Yes, this should be subclass of O21 Measurement. We need further 
elaboration about how measurements relate to the approximation of things 
of interest. I found this to be quite diverse, and adding to this class 
a repetition of all topological relations confusing. E18 still has a 
Presence directly related.


Best,

Martin

On 3/8/2021 10:07 AM, Hiebel, Gerald wrote:


Dear Martin and all,

thanks for taking this forward and the suggested proposition, which 
defines the process very well.


One question I have is how to relate the Position Measurement to the 
measured object (E18 or S10).


I believe the E93 Presence is the correct way for it, but we may run 
into a problem, as E18 is no longer a subclass of E92 and therefore 
not of E93.


For implementation simplicity a shortcut to a measured object in the 
form of a specific property would be nice, or could we use O24 measured ?


If so, should we make  Position Measurement  a subclass of O21 
Measurement and maybe include an example that shows the modelling.


But maybe I did not see an obvious solution.

Best,

Gerald

*From: *Crm-sig  on behalf of Martin 
Doerr 

*Date: *Monday, 1. March 2021 at 21:31
*To: *crm-sig 
*Subject: *[Crm-sig] Issue 388 measuring position

Dear All,

I revise my previous proposal for measuring positions:



Any position measurement is based

on triangulation with multiples distances to reference points and 
angle measurements. GPS measures distances to satellites. Distances 
are Dimensions. If directed distances use georeferenced directions, 
i.e. angle to the rotation axis of earth, etc. angles


are again dimensions. Hence, a position measurement is an evaluation 
of a combination of multiple associated distance and angle 
measurements from a particular spot to certain reference points of 
known position in the same reference space. If stars are used,


they constitute (extremely) distant reference points. Gravity and 
Earth Magnetic Field also provide reference directions for angle 
measurements that do not need a second reference point. Classical 
longitude measurements use temporal simultaneity of a common


event with a reference location, which evaluates to an angle. All 
methods are fairly complex, but the details are a standard routine or 
even hidden in a modern GPS module.


Therefore

we argue that position measurement is a specific (composite) 
observation which results in a position expression, but the 
constituent dimensions may or may not be documented.


Hence,

P40 observed dimension (was observed in): E54 Dimension may not be 
instantiated.


All

position measurements are approximations of other places. Therefore, 
they result in a declarative place defined by an E94 Space Primitive. 
Since in general we talk about moving reference spaces, moving things 
and evolving processes, the time of measurement


is essential. We take it either to be the time-span of the 
measurement, or a narrower time-span which covers the contributing 
time-critical observations. In essence, this defines a declarative 
spacetime box (volume), which again is an approximation. It appears


to me that such an approximation would normally be used to determine 
parts of the extent of some instance of Presence by overlap, coverage 
or containment.


Sxxx

Position Measurement

Subclass

of:        E16 Attribute Assignment

Scope

note:     This class comprises activities of measuring positions in 
space and time. The measured position is intended to approximate a 
part or all of the extent of the presence (instance of E93 Presence) 
of an instance of E18 Physical Thing or E4 Period of


interest, such as the outer walls of an excavated settlement, the 
position of a ship sailing or the start and end of athlete’s run in a 
competition. Characteristically, a theodolite or GPS device may be 
positioned on some persistent feature. Measuring the


position of the device will yield an approximation of the position of 
the feature of interest. Alternatively, some material item may be 
observed moving through a measured position at a given time.


A

position measurement is an evaluation of a combination of measurement 
of multiple associated distances and/or angles (instances of E54 
Dimension) from a particular spot to certain reference points of 
previously known position in the same reference space.


Often, the observed constituting dimensions are not documented, or 
hidden in an electronic device software.The measured position is given 
as an E94 Space Primitive corresponding to a declarative place. 
Together with the measured time-span covering the time-critical


observations it forms a spacetime volume, which should normally 
overlap with the spatiotemporal extent of the thing or phenomenon of 
interest.


Properties:

Oxx1

determined position (was determined by): E94 Space Primitive

Oxx2

has validity time-span (is position validity for): E52 Time-Span

We

may now formulate the approximation to the things

Re: [Crm-sig] Issue 388 measuring position

[Hiebel, Gerald]

Dear Martin and all,

thanks for taking this forward and the suggested proposition, which defines the 
process very well.

One question I have is how to relate the Position Measurement to the measured 
object (E18 or S10).
I believe the E93 Presence is the correct way for it, but we may run into a 
problem, as E18 is no longer a subclass of E92 and therefore not of E93.

For implementation simplicity a shortcut to a measured object in the form of a 
specific property would be nice, or could we use O24 measured ?
If so, should we make  Position Measurement  a subclass of O21 Measurement and 
maybe include an example that shows the modelling.

But maybe I did not see an obvious solution.
Best,
Gerald


From: Crm-sig  on behalf of Martin Doerr 

Date: Monday, 1. March 2021 at 21:31
To: crm-sig 
Subject: [Crm-sig] Issue 388 measuring position

Dear All,

I revise my previous proposal for measuring positions:




Any position measurement is based

on triangulation with multiples distances to reference points and angle 
measurements. GPS measures distances to satellites. Distances are Dimensions. 
If directed distances use georeferenced directions, i.e. angle to the rotation 
axis of earth, etc. angles

are again dimensions. Hence, a position measurement is an evaluation of a 
combination of multiple associated distance and angle measurements from a 
particular spot to certain reference points of known position in the same 
reference space. If stars are used,

they constitute (extremely) distant reference points. Gravity and Earth 
Magnetic Field also provide reference directions for angle measurements that do 
not need a second reference point. Classical longitude measurements use 
temporal simultaneity of a common

event with a reference location, which evaluates to an angle. All methods are 
fairly complex, but the details are a standard routine or even hidden in a 
modern GPS module.


Therefore

we argue that position measurement is a specific (composite) observation which 
results in a position expression, but the constituent dimensions may or may not 
be documented.

Hence,

P40 observed dimension (was observed in): E54 Dimension may not be instantiated.



All

position measurements are approximations of other places. Therefore, they 
result in a declarative place defined by an E94 Space Primitive. Since in 
general we talk about moving reference spaces, moving things and evolving 
processes, the time of measurement

is essential. We take it either to be the time-span of the measurement, or a 
narrower time-span which covers the contributing time-critical observations. In 
essence, this defines a declarative spacetime box (volume), which again is an 
approximation. It appears

to me that such an approximation would normally be used to determine parts of 
the extent of some instance of Presence by overlap, coverage or containment.


Sxxx

Position Measurement

Subclass

of:E16 Attribute Assignment

Scope

note: This class comprises activities of measuring positions in space and 
time. The measured position is intended to approximate a part or all of the 
extent of the presence (instance of E93 Presence) of an instance of E18 
Physical Thing or E4 Period of

interest, such as the outer walls of an excavated settlement, the position of a 
ship sailing or the start and end of athlete’s run in a competition. 
Characteristically, a theodolite or GPS device may be positioned on some 
persistent feature. Measuring the

position of the device will yield an approximation of the position of the 
feature of interest. Alternatively, some material item may be observed moving 
through a measured position at a given time.

A

position measurement is an evaluation of a combination of measurement of 
multiple associated distances and/or angles (instances of E54 Dimension) from a 
particular spot to certain reference points of previously known position in the 
same reference space.

Often, the observed constituting dimensions are not documented, or hidden in an 
electronic device software.The measured position is given as an E94 Space 
Primitive corresponding to a declarative place. Together with the measured 
time-span covering the time-critical

observations it forms a spacetime volume, which should normally overlap with 
the spatiotemporal extent of the thing or phenomenon of interest.

Properties:

Oxx1

determined position (was determined by): E94 Space Primitive

Oxx2

has validity time-span (is position validity for): E52 Time-Span

We

may now formulate the approximation to the things of interest, e.g.


Oxx3

overlaps with presence: E93 Presence.


But

the time=span of this presence is already implicit in the time-span of validity.


If

we use:


Oxx3

overlaps with presence of: , we need a property for E18 and another for E4…


Another

use case is when someone wants to determine if she is at a particular 
declarative place: Fisherman now mark positions in the sea with GPS, in order 
to return

Re: [Crm-sig] Issue 388 measuring position

[Øyvind Eide]

Dear Martin,

it makes sense to me. I will try to formulate something and thus find out if I 
actually think something is missing. 

Regards,

Øyvind

> Am 05.03.2021 um 17:47 schrieb Martin Doerr :
> 
> Dear Øyvind,
> 
> Indeed I'd call this still a form of triangulation. If you determine the 
> relative position by (Dx,Dy), you create a rectangular triangle, with your 
> distance walked being the hypotenuse.
> 
> If you have a nice proposal text to add, welcome! So far, I think I have 
> covered analogue practices.
> 
> All the best,
> 
> Martin
> 
> On 3/5/2021 5:11 PM, Øyvind Eide wrote:
>> Dear Martin,
>> 
>> I am considering a possible practical counter-example from my own manual 
>> measurement experience. I am not sure if it is relevant but maybe the first 
>> sentence (”Any position measurement is based on triangulation with multiples 
>> distances to reference points and angle measurements”) should be modified.
>> 
>> I am mapping the location of a boulder. Using a compass and my steps, fairly 
>> well calibrated to one meter, I measure the distance and direction from my 
>> fix point, in this case the spot where a creek is crossing a path.
>> 
>> The fix point itself is established through stereo aerial photography and 
>> thus, based on a sort of triangulation. But my measurement from the fix 
>> point and the boulder is based on the distance and direction from the single 
>> fix point.
>> 
>> Maybe it makes sense to still call this a triangulation as the compass shows 
>> the direction to the magnetic north. 
>> 
>> Whatever can be argued about this, maybe it makes sense to add to the GPS 
>> descriptions a bit more on analogue measurement practices? They were the 
>> basis for a massive amount of museum and cultural heritage documentation. 
>> 
>> All the best,
>> 
>> Øyvind
>> 
>>> Am 01.03.2021 um 21:19 schrieb Martin Doerr >> >:
>>> 
>>> Dear All,
>>> 
>>> I revise my previous proposal for measuring positions:
>>> 
>>> 
>>> Any position measurement is based on triangulation with multiples distances 
>>> to reference points and angle measurements. GPS measures distances to 
>>> satellites. Distances are Dimensions. If directed distances use 
>>> georeferenced directions, i.e. angle to the rotation axis of earth, etc. 
>>> angles are again dimensions. Hence, a position measurement is an evaluation 
>>> of a combination of multiple associated distance and angle measurements 
>>> from a particular spot to certain reference points of known position in the 
>>> same reference space. If stars are used, they constitute (extremely) 
>>> distant reference points. Gravity and Earth Magnetic Field also provide 
>>> reference directions for angle measurements that do not need a second 
>>> reference point. Classical longitude measurements use temporal simultaneity 
>>> of a common event with a reference location, which evaluates to an angle. 
>>> All methods are fairly complex, but the details are a standard routine or 
>>> even hidden in a modern GPS module. 
>>> 
>>> Therefore we argue that position measurement is a specific (composite) 
>>> observation which results in a position expression, but the constituent 
>>> dimensions may or may not be documented.
>>> Hence, P40 observed dimension (was observed in): E54 Dimension may not be 
>>> instantiated.
>>>  
>>> All position measurements are approximations of other places. Therefore, 
>>> they result in a declarative place defined by an E94 Space Primitive. Since 
>>> in general we talk about moving reference spaces, moving things and 
>>> evolving processes, the time of measurement is essential. We take it either 
>>> to be the time-span of the measurement, or a narrower time-span which 
>>> covers the contributing time-critical observations. In essence, this 
>>> defines a declarative spacetime box (volume), which again is an 
>>> approximation. It appears to me that such an approximation would normally 
>>> be used to determine parts of the extent of some instance of Presence by 
>>> overlap, coverage or containment. 
>>> 
>>> Sxxx Position Measurement
>>> 
>>> Subclass of:E16 Attribute Assignment
>>> 
>>> Scope note: This class comprises activities of measuring positions in 
>>> space and time. The measured position is intended to approximate a part or 
>>> all of the extent of the presence (instance of E93 Presence) of an instance 
>>> of E18 Physical Thing or E4 Period of interest, such as the outer walls of 
>>> an excavated settlement, the position of a ship sailing or the start and 
>>> end of athlete’s run in a competition. Characteristically, a theodolite or 
>>> GPS device may be positioned on some persistent feature. Measuring the 
>>> position of the device will yield an approximation of the position of the 
>>> feature of interest. Alternatively, some material item may be observed 
>>> moving through a measured position at a given time. 
>>> 
>>> A position measurement is an evaluation of a 

Re: [Crm-sig] Issue 388 measuring position

[Martin Doerr]

Dear Øyvind,

Indeed I'd call this still a form of triangulation. If you determine the 
relative position by (Dx,Dy), you create a rectangular triangle, with 
your distance walked being the hypotenuse.


If you have a nice proposal text to add, welcome! So far, I think I have 
covered analogue practices.


All the best,

Martin

On 3/5/2021 5:11 PM, Øyvind Eide wrote:

Dear Martin,

I am considering a possible practical counter-example from my own 
manual measurement experience. I am not sure if it is relevant but 
maybe the first sentence (”Any position measurement is based on 
triangulation with multiples distances to reference points and angle 
measurements”) should be modified.


I am mapping the location of a boulder. Using a compass and my steps, 
fairly well calibrated to one meter, I measure the distance and 
direction from my fix point, in this case the spot where a creek is 
crossing a path.


The fix point itself is established through stereo aerial photography 
and thus, based on a sort of triangulation. But my measurement from 
the fix point and the boulder is based on the distance and direction 
from the single fix point.


Maybe it makes sense to still call this a triangulation as the compass 
shows the direction to the magnetic north.


Whatever can be argued about this, maybe it makes sense to add to the 
GPS descriptions a bit more on analogue measurement practices? They 
were the basis for a massive amount of museum and cultural heritage 
documentation.


All the best,

Øyvind

Am 01.03.2021 um 21:19 schrieb Martin Doerr >:


Dear All,

I revise my previous proposal for measuring positions:


Any position measurement is based on triangulation with multiples 
distances to reference points and angle measurements. GPS measures 
distances to satellites. Distances are Dimensions. If directed 
distances use georeferenced directions, i.e. angle to the rotation 
axis of earth, etc. angles are again dimensions. Hence, a position 
measurement is an evaluation of a combination of multiple associated 
distance and angle measurements from a particular spot to certain 
reference points of known position in the same reference space. If 
stars are used, they constitute (extremely) distant reference points. 
Gravity and Earth Magnetic Field also provide reference directions 
for angle measurements that do not need a second reference point. 
Classical longitude measurements use temporal simultaneity of a 
common event with a reference location, which evaluates to an angle. 
All methods are fairly complex, but the details are a standard 
routine or even hidden in a modern GPS module.


Therefore we argue that position measurement is a specific 
(composite) observation which results in a position expression, but 
the constituent dimensions may or may not be documented.
Hence, P40 observed dimension (was observed in): E54 Dimension may 
not be instantiated.


All position measurements are approximations of other places. 
Therefore, they result in a declarative place defined by an E94 Space 
Primitive. Since in general we talk about moving reference spaces, 
moving things and evolving processes, the time of measurement is 
essential. We take it either to be the time-span of the measurement, 
or a narrower time-span which covers the contributing time-critical 
observations. In essence, this defines a declarative spacetime box 
(volume), which again is an approximation. It appears to me that such 
an approximation would normally be used to determine parts of the 
extent of some instance of Presence by overlap, coverage or containment.


Sxxx Position Measurement

Subclass of: E16 Attribute Assignment

Scope note:     This class comprises activities of measuring 
positions in space and time. The measured position is intended to 
approximate a part or all of the extent of the presence (instance of 
E93 Presence) of an instance of E18 Physical Thing or E4 Period of 
interest, such as the outer walls of an excavated settlement, the 
position of a ship sailing or the start and end of athlete’s run in a 
competition. Characteristically, a theodolite or GPS device may be 
positioned on some persistent feature. Measuring the position of the 
device will yield an approximation of the position of the feature of 
interest. Alternatively, some material item may be observed moving 
through a measured position at a given time.


A position measurement is an evaluation of a combination of 
measurement of multiple associated distances and/or angles (instances 
of E54 Dimension) from a particular spot to certain reference points 
of previously known position in the same reference space.Often, the 
observed constituting dimensions are not documented, or hidden in an 
electronic device software.The measured position is given as an E94 
Space Primitive corresponding to a declarative place. Together with 
the measured time-span covering the time-critical observations it 
forms a spacetime volume, which 

Re: [Crm-sig] Issue 388 measuring position

[Øyvind Eide]

Dear Martin,

I am considering a possible practical counter-example from my own manual 
measurement experience. I am not sure if it is relevant but maybe the first 
sentence (”Any position measurement is based on triangulation with multiples 
distances to reference points and angle measurements”) should be modified.

I am mapping the location of a boulder. Using a compass and my steps, fairly 
well calibrated to one meter, I measure the distance and direction from my fix 
point, in this case the spot where a creek is crossing a path.

The fix point itself is established through stereo aerial photography and thus, 
based on a sort of triangulation. But my measurement from the fix point and the 
boulder is based on the distance and direction from the single fix point.

Maybe it makes sense to still call this a triangulation as the compass shows 
the direction to the magnetic north. 

Whatever can be argued about this, maybe it makes sense to add to the GPS 
descriptions a bit more on analogue measurement practices? They were the basis 
for a massive amount of museum and cultural heritage documentation. 

All the best,

Øyvind

> Am 01.03.2021 um 21:19 schrieb Martin Doerr :
> 
> Dear All,
> 
> I revise my previous proposal for measuring positions:
> 
> 
> Any position measurement is based on triangulation with multiples distances 
> to reference points and angle measurements. GPS measures distances to 
> satellites. Distances are Dimensions. If directed distances use georeferenced 
> directions, i.e. angle to the rotation axis of earth, etc. angles are again 
> dimensions. Hence, a position measurement is an evaluation of a combination 
> of multiple associated distance and angle measurements from a particular spot 
> to certain reference points of known position in the same reference space. If 
> stars are used, they constitute (extremely) distant reference points. Gravity 
> and Earth Magnetic Field also provide reference directions for angle 
> measurements that do not need a second reference point. Classical longitude 
> measurements use temporal simultaneity of a common event with a reference 
> location, which evaluates to an angle. All methods are fairly complex, but 
> the details are a standard routine or even hidden in a modern GPS module. 
> 
> Therefore we argue that position measurement is a specific (composite) 
> observation which results in a position expression, but the constituent 
> dimensions may or may not be documented.
> Hence, P40 observed dimension (was observed in): E54 Dimension may not be 
> instantiated.
>  
> All position measurements are approximations of other places. Therefore, they 
> result in a declarative place defined by an E94 Space Primitive. Since in 
> general we talk about moving reference spaces, moving things and evolving 
> processes, the time of measurement is essential. We take it either to be the 
> time-span of the measurement, or a narrower time-span which covers the 
> contributing time-critical observations. In essence, this defines a 
> declarative spacetime box (volume), which again is an approximation. It 
> appears to me that such an approximation would normally be used to determine 
> parts of the extent of some instance of Presence by overlap, coverage or 
> containment. 
> 
> Sxxx Position Measurement
> 
> Subclass of:E16 Attribute Assignment
> 
> Scope note: This class comprises activities of measuring positions in 
> space and time. The measured position is intended to approximate a part or 
> all of the extent of the presence (instance of E93 Presence) of an instance 
> of E18 Physical Thing or E4 Period of interest, such as the outer walls of an 
> excavated settlement, the position of a ship sailing or the start and end of 
> athlete’s run in a competition. Characteristically, a theodolite or GPS 
> device may be positioned on some persistent feature. Measuring the position 
> of the device will yield an approximation of the position of the feature of 
> interest. Alternatively, some material item may be observed moving through a 
> measured position at a given time. 
> 
> A position measurement is an evaluation of a combination of measurement of 
> multiple associated distances and/or angles (instances of E54 Dimension) from 
> a particular spot to certain reference points of previously known position in 
> the same reference space. Often, the observed constituting dimensions are not 
> documented, or hidden in an electronic device software.The measured position 
> is given as an E94 Space Primitive corresponding to a declarative place. 
> Together with the measured time-span covering the time-critical observations 
> it forms a spacetime volume, which should normally overlap with the 
> spatiotemporal extent of the thing or phenomenon of interest. 
> 
> Properties:
> 
> Oxx1 determined position (was determined by): E94 Space Primitive
> 
> Oxx2 has validity time-span (is position validity for): E52 Time-Span
> 
> We may now 

[Crm-sig] Issue 388 measuring position

[Martin Doerr]

Dear All,

I revise my previous proposal for measuring positions:


Any position measurement is based on triangulation with multiples 
distances to reference points and angle measurements. GPS measures 
distances to satellites. Distances are Dimensions. If directed distances 
use georeferenced directions, i.e. angle to the rotation axis of earth, 
etc. angles are again dimensions. Hence, a position measurement is an 
evaluation of a combination of multiple associated distance and angle 
measurements from a particular spot to certain reference points of known 
position in the same reference space. If stars are used, they constitute 
(extremely) distant reference points. Gravity and Earth Magnetic Field 
also provide reference directions for angle measurements that do not 
need a second reference point. Classical longitude measurements use 
temporal simultaneity of a common event with a reference location, which 
evaluates to an angle. All methods are fairly complex, but the details 
are a standard routine or even hidden in a modern GPS module.



Therefore we argue that position measurement is a specific (composite) 
observation which results in a position expression, but the constituent 
dimensions may or may not be documented.


Hence, P40 observed dimension (was observed in): E54 Dimension may not 
be instantiated.


All position measurements are approximations of other places. Therefore, 
they result in a declarative place defined by an E94 Space Primitive. 
Since in general we talk about moving reference spaces, moving things 
and evolving processes, the time of measurement is essential. We take it 
either to be the time-span of the measurement, or a narrower time-span 
which covers the contributing time-critical observations. In essence, 
this defines a declarative spacetime box (volume), which again is an 
approximation. It appears to me that such an approximation would 
normally be used to determine parts of the extent of some instance of 
Presence by overlap, coverage or containment.



Sxxx Position Measurement

Subclass of:        E16 Attribute Assignment

Scope note:     This class comprises activities of measuring positions 
in space and time. The measured position is intended to approximate a 
part or all of the extent of the presence (instance of E93 Presence) of 
an instance of E18 Physical Thing or E4 Period of interest, such as the 
outer walls of an excavated settlement, the position of a ship sailing 
or the start and end of athlete’s run in a competition. 
Characteristically, a theodolite or GPS device may be positioned on some 
persistent feature. Measuring the position of the device will yield an 
approximation of the position of the feature of interest. Alternatively, 
some material item may be observed moving through a measured position at 
a given time.


A position measurement is an evaluation of a combination of measurement 
of multiple associated distances and/or angles (instances of E54 
Dimension) from a particular spot to certain reference points of 
previously known position in the same reference space.Often, the 
observed constituting dimensions are not documented, or hidden in an 
electronic device software.The measured position is given as an E94 
Space Primitive corresponding to a declarative place. Together with the 
measured time-span covering the time-critical observations it forms a 
spacetime volume, which should normally overlap with the spatiotemporal 
extent of the thing or phenomenon of interest.


Properties:

Oxx1 determined position (was determined by): E94 Space Primitive

Oxx2 has validity time-span (is position validity for): E52 Time-Span

We may now formulate the approximation to the things of interest, e.g.


Oxx3 overlaps with presence: E93 Presence.


But the time=span of this presence is already implicit in the time-span 
of validity.



If we use:


Oxx3 overlaps with presence of: , we need a property for E18 and 
another for E4…



Another use case is when someone wants to determine if she is at a 
particular declarative place: Fisherman now mark positions in the sea 
with GPS, in order to return to the same spot...




Opinions?

To be discussed!

Martin

--

 Dr. Martin Doerr
  
 Honorary Head of the

 Center for Cultural Informatics
 
 Information Systems Laboratory

 Institute of Computer Science
 Foundation for Research and Technology - Hellas (FORTH)
  
 N.Plastira 100, Vassilika Vouton,

 GR70013 Heraklion,Crete,Greece
 
 Vox:+30(2810)391625

 Email: mar...@ics.forth.gr
 Web-site: http://www.ics.forth.gr/isl

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