Geographic coordinate - latitude and longitude

[ap-peh]

Description of the issue

The definition of the entity "geographic coordinate" says: "A geographic coordinate is an information content entity explicitly stating the geographic position of a zero-dimensional spatial region on Earth, by using a set of numbers with respect to a geographic coordinate system." But how can a "set of numbers" be added to the entity "geographic coordinate", where the numbers express the latitude and longitude?

Ideas of solution

My suggestion is to add the entities "latitude" and "longitude" for example, which can be assigned a value via the data property "has number". Furthermore, it has to be thought about how the new entities "latitude" and "longitude" can be related to the entity "geographic coordinate".

Workflow checklist

• [ ] I discussed the issue with someone else than me before working on a solution
• [ ] I already read the latest version of the workflow for this repository
• [ ] The goal of this ontology is clear to me

I am aware that

• [ ] every entry in the ontology should have a definition
• [ ] classes should arise from concepts rather than from words

[l-emele]

I think, we should import:

• cartesian spatial coordinate datum (IAO_0000400): A cartesian spatial coordinate datum is a representation of a point in a spatial region, in which equal changes in the magnitude of a coordinate value denote length qualities with the same magnitude
  • one dimensional cartesian spatial coordinate datum (IAO_0000401) A cartesion spatial coordinate datum that uses one value to specify a position along a one dimensional spatial region
  • two dimensional cartesian spatial coordinate datum (IAO_0000402) A cartesion spatial coordinate datum that uses two values to specify a position within a two dimensional spatial region
  • three dimensional cartesian spatial coordinate datum (IAO_0000403) A cartesion spatial coordinate datum that uses three values to specify a position within a three dimensional spatial region

And then redefine geographic coordinate to: A geographic coordinate is ~an information content entity~ a two dimensional cartesian spatial coordinate datum explicitly stating the geographic position of a zero-dimensional spatial region on Earth, by using a set of numbers with respect to a geographic coordinate system.

Proposals for latitude and longitude:

• latitude: A latitude is a quantity value that is part of a geographic coordinate and quantifies the angle from a zero-dimentional spatial region on the Earth's surface to the equatorial plane.
• longitude: A latitude is a quantity value that is part of a geographic coordinate and quantifies the angle east or west of a from a zero-dimentional spatial region on the Earth's surface to the reference meridian between the two geographical poles.

Inspired by the definitions of http://semanticscience.org/resource/SIO_000318 and https://ontobee.org/ontology/SIO?iri=http://semanticscience.org/resource/SIO_000319

[ap-peh]

Adding coordinate data properties

• Data property “has measurement value” (http://purl.obolibrary.org/obo/IAO_0000004)
• Data property “has x coordinate value” (http://purl.obolibrary.org/obo/IAO_0000404)
• Data property “has y coordinate value” (http://purl.obolibrary.org/obo/IAO_0000406)
• Data property “has z coordinate value” (http://purl.obolibrary.org/obo/IAO_0000405)

[viktorwichern]

I think, we should import:

• cartesian spatial coordinate datum (IAO_0000400): A cartesian spatial coordinate datum is a representation of a point in a spatial region, in which equal changes in the magnitude of a coordinate value denote length qualities with the same magnitude

Since apparently a lot of Ontologies are using that system, it seems to work. I think the definition is extremely convoluted though. Also, two minor complaints:

1. We don't have the object property denotes which is part of the definition and axioms of the IAO class. So maybe we should import that as well. http://purl.obolibrary.org/obo/IAO_0000219

Definition: A primitive, instance-level, relation obtaining between an information content entity and some portion of reality. Denotation is what happens when someone creates an information content entity E in order to specifically refer to something. The only relation between E and the thing is that E can be used to 'pick out' the thing. This relation connects those two together. sense 3: To signify directly; refer to specifically

2. I think "in which equal changes in the magnitude of a coordinate value denote length qualities with the same magnitude" is a horrible way to describe it. I am still not sure if I understood correctly. If it is a representation of a point in a spatial region, how can changes to the coordinate value denote length qualities? A point has no length. They are probably referring to the lengths of the axis, but those are not even mentioned, which is weird considering that is the most important part of the system, right?

I think a definition in this direction would be better (I know this is for the system and not the datum, we would then add the corresponding information content entity as well, which would also solve my next concern):

A Cartesian coordinate system is a coordinate system that specifies each point uniquely in a plane by a pair of numerical coordinates, which are the signed distances from the point to two fixed perpendicular directed lines, measured in the same unit of length. http://purl.obolibrary.org/obo/STATO_0000009

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And then redefine geographic coordinate to: A geographic coordinate is ~an information content entity~ a two dimensional cartesian spatial coordinate datum explicitly stating the geographic position of a zero-dimensional spatial region on Earth, by using a set of numbers with respect to a geographic coordinate system.

I am fine with that proposal, but maybe we should define geographic coordinate system as well, since it is the basis of the definition. That definition could maybe be something like "A geographic coordinate system is a cartesian coordinate system that represents the Earth".

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Proposals for latitude and longitude:

• latitude: A latitude is a quantity value that is part of a geographic coordinate and quantifies the angle from a zero-dimentional spatial region on the Earth's surface to the equatorial plane.
• longitude: A latitude is a quantity value that is part of a geographic coordinate and quantifies the angle east or west of a from a zero-dimentional spatial region on the Earth's surface to the reference meridian between the two geographical poles.

I am fine with these proposals.

[l-emele]

2. I think "in which equal changes in the magnitude of a coordinate value denote length qualities with the same magnitude" is a horrible way to describe it. I am still not sure if I understood correctly. If it is a representation of a point in a spatial region, how can changes to the coordinate value denote length qualities? A point has no length. They are probably referring to the lengths of the axis, but those are not even mentioned, which is weird considering that is the most important part of the system, right?

I understand the definition in way that the "in which equal changes ..." part refers to the spatial region and not to the point. It is a characteristic of such a spatial region that "equal changes in the magnitude of a coordinate value denote length qualities with the same magnitude" -- and not a characteristic of the point!

[viktorwichern]

I understand the definition in way that the "in which equal changes ..." part refers to the spatial region and not to the point. It is a characteristic of such a spatial region that "equal changes in the magnitude of a coordinate value denote length qualities with the same magnitude" -- and not a characteristic of the point!

You are probably right, I still think that the definition is just not that well articulated. I am okay either way, but I would prefer we add cartesian coordinate system as well as cartesian coordinate system datum.

[stap-m]

And then redefine geographic coordinate to: A geographic coordinate is ~an information content entity~ a two dimensional cartesian spatial coordinate datum explicitly stating the geographic position of a zero-dimensional spatial region on Earth, by using a set of numbers with respect to a geographic coordinate system.

I am fine with that proposal, but maybe we should define geographic coordinate system as well, since it is the basis of the definition. That definition could maybe be something like "A geographic coordinate system is a cartesian coordinate system that represents the surface of the Earth".

Cartesian coordinate systems are rectangular coordinate systems. Geographic coordinate systems are usually spherical coordinate systems. (Sorry for referencing wikipedia)

Importing the cartesian stuff from IAO is nice, but does't serve for this use case... Therefore, I propose for a quick solution: Leave geographic coordinate as is and implement latitude and longitude as proposed, until we are done with the quantity values.

[l-emele]

Cartesian coordinate systems are rectangular coordinate systems. Geographic coordinate systems are usually spherical coordinate systems. (Sorry for referencing wikipedia)

Geographic coordinates on a sphere are rectangular coordinate systems, too. That is why I thought that matches. But thinking again, the in which equal changes in the magnitude of a coordinate value denote length qualities with the same magnitude part of the definition does not hold on a sphere as the distance between two longitudes depends on the latitude.

I just had a look into GEO, there is the following structure:

• data item (IAO_0000027), already in the OEO
  • measurement datum (IAO_0000109): An information content entity that is intended to be a truthful statement about something (modulo, e.g., measurement precision or other systematic errors) and is constructed/acquired by a method which reliably tends to produce (approximately) truthful statements.
    • geodetic coordinate measurement datum (GEO_000000787): A measurement of location on the Earth that uses a single number to specify a coordinate in a coordinate system known as a geodetic datum
      • latitude coordinate measurement datum (OBI_0001620): A measurement datum that is the measure of the latitude coordinate of a site. Alternative term: latitude
      • longitude coordinate measurement datum (OBI_0001621): A measurement datum that is the measure of the longitude coordinate of a site. Alternative term: longitude

[stap-m]

The GEO structure looks suitable for our purposes.

[l-emele]

So we need to import the following three classes: geodetic coordinate measurement datum (GEO_000000787), latitude coordinate measurement datum (OBI_0001620) and longitude coordinate measurement datum (OBI_0001621). Who can do that?

[l-emele]

So we need to import the following three classes: geodetic coordinate measurement datum (GEO_000000787), latitude coordinate measurement datum (OBI_0001620) and longitude coordinate measurement datum (OBI_0001621). Who can do that?

@h-spinde @nelekoehler @viktorwichern @stap-m : Who can do this import?

[l-emele]

From OEO dev meeting 76: This issue was not yet implemented as it needs to be rediscussed after the restructuring of the quantity values.

[stap-m]

I can do the import. @nelekoehler any idea of how to relate to quantity values?