Talk:Discrete global grid

New OGC API - DGGS Standard

Review in light of the new OGC API - DGGS Standard, which is an implementation standard with concrete requirements for interoperability, while Abstract Specification Topic 21 (latest version 2.0) was conceptual. It defines requirements for implementing servers supporting querying and retrieving data using zone identifiers, and provides example Discrete Global Grid Reference Systems (Annex B).

Check

• Other examples of DGG-variants for geocoding: http://geocode-encyclopedia.info
• Terminology, names for projection types: List_of_map_projections
• comparisons:
  • https://www.fulcrumapp.com/blog/comparing-address-and-coordinate-systems/
  • http://www2.unb.ca/~estef/papers/go_geomatics_stefanakis_march_2016.pdf
• ....

Other DGGs:

• http://near-goos.jodc.go.jp/data_format/position-code.html
• Japan grid square code (JIS X 0410): [pyjpmesh](https://github.com/ymoch/pyjpmesh), ...check other (link working?), [ref1](https://ieeexplore.ieee.org/document/8258450/), [ref2](http://www.j-shis.bosai.go.jp/en/faq-250mmesh#more-42)
  • A 250m-mesh is a square area of 7.5 arc-seconds latitude x 11.25 arc-seconds longitude (about 250m x 250m). This geographical coordinate system adopts the standard grid square (mesh code N) based on Tokyo Datum. 250m-mesh code is a part of the divided grid square code defined by JIS X 0410/AMENDMENT1:2002.

Review all article using OGC standard

The new OGC DGGS standard entitled “Topic 21: Discrete Global Grid Systems Abstract Specification” is online! It includes important information on definitions, conventions, functional algorithms, the core data model and more... see:

• HTML https://docs.opengeospatial.org/as/15-104r5/15-104r5.html
• PDF https://portal.opengeospatial.org/files/15-104r5
• Problem Statement at http://www.opengeospatial.org/projects/groups/dggsdwg

Krauss (talk) 23:51, 19 April 2019 (UTC)

You can use also didactic texts and discussions:

• PDF of "Discrete global grid systems", Perry R. Peterson
• explanations of John Merola in a pitneybowes.com discussion

grabularity

What does grabularity mean? Should this be granularity? — Preceding unsigned comment added by 67.188.178.167 (talk) 03:19, 15 December 2018 (UTC)

corrected

Notes about key-words and references

• About S2 geometry, the cube as used before "S2 Geometry", by "SAND" in the end of 1990s, see http://www.cs.umd.edu/~hjs/pubs/alborzidgg00.pdf
• "Fine grid" and "Coarse grid" (or grid cells). Example of use of the terms in this CFD article (CFD = Computational Fluid Dynamics)
• ...

About flat and hierarchical grids

The term "flat" is perhaps preferable to the term "non-hierarchical". See "flat vs hierarchical" organizations, design architectures, clusters, structures, etc. About properties, see this didactic article comparing both for spatial-partition in games, as decisions:

• flat grid, advantages:
  • Simpler: the flat data structure is simpler, and it is simpler to implement.
  • Memory usage is constant. (spatial partition can often be fixed ahead of time).
  • Faster: it can be faster to calculate or update, when objects change their positions.

• hierarchical grid, advantages:
  • It handles empty space more efficiently.
  • Neighboring objects can be moved quickly.
  • The partitions can be imbalanced. When objects clump together, you get better performance, avoiding to waste memory in the empty areas.

Grid classification

It is possible to adapt Grid classification article, and generalize relationships of the DGG areas...