[Crm-sig] Issue 388 measuring position

Hiebel, Gerald Gerald.Hiebel at uibk.ac.at
Mon Mar 8 10:07:39 EET 2021

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.

From: Crm-sig <crm-sig-bounces at ics.forth.gr> on behalf of Martin Doerr <martin at ics.forth.gr>
Date: Monday, 1. March 2021 at 21:31
To: crm-sig <Crm-sig at 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.


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.


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


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.


Position Measurement


of:        E16 Attribute Assignment


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.


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.



determined position (was determined by): E94 Space Primitive


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


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


overlaps with presence: E93 Presence.


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


we use:


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


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...


To be discussed!




 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


 Email: martin at ics.forth.gr<mailto:martin at ics.forth.gr>

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