topic Re: What does the DGGS mean? in Coordinate Reference Systems Questions

What does the DGGS mean?

Oliver_Burdekin — Thu, 26 Oct 2017 07:19:17 GMT

Interesting news from the OGC that the Discrete Global Grid System has been approved. Read more about it here:

OGC announces a new standard that improves the way information is referenced to the earth | OGC

What does this mean for us as GIS folk and how (and when) will we be able to make use of it? In fact, is it already available in ESRI software? Is this the end of the Web Mercator? What about threed? So many questions.

Discuss

Re: What does the DGGS mean?

SimonKettle — Thu, 26 Oct 2017 09:39:40 GMT

As this new system was only announced yesterday these are all valid questions that should be explored further. I must admit I am still trying to clarify the system in my mind and this additional information on the OGC website that will be of interest. I understand that this system redefines a grid to better comply with spherical geometry (i.e. the surface of the Earth) where a traditional grid is a simple array of rectangles this new grid will try to minimise the alterations in grid shape based on scale. You will have noticed the new grid contains a system of hexagons. These hexagons form a hierarchical tessellation of the entire Earth to produce equal-area grids.

I hope this document will start to explain the system further and I see that ESRI was involved with the OGC in the making of this system so I would hope to hear from them at some point.

Re: What does the DGGS mean?

Oliver_Burdekin — Thu, 26 Oct 2017 09:44:56 GMT

Thanks Simon. I was not asking specific questions for myself but aiming to start awider discussion of what effect DGGS will have. It's certianly an exciting development and thank you for your post. The more information the better at this stage

Cheers,

Oliver

Re: What does the DGGS mean?

DanPatterson_Retired — Thu, 26 Oct 2017 09:47:51 GMT

it seems to focus on showing parts of earth seamlessly, with little to no information on how the locational information will be used in analysis that requires coordinates to perform calculations (ie distance direction). Perhaps its focus is on visualization.

Re: What does the DGGS mean?

SimonKettle — Thu, 26 Oct 2017 10:41:07 GMT

I'm not sure of the specifics but I read that you will be able to translate cell addresses to other coordinate reference systems...so I understand that one might do geospatial analysis and then convert the results into a DGGS to visualize information essentially where each cell will be equal in area.

Re: What does the DGGS mean?

Oliver_Burdekin — Thu, 26 Oct 2017 10:43:02 GMT

In many ways it reminds me of a hexagonal what3words.

Re: What does the DGGS mean?

SimonKettle — Thu, 26 Oct 2017 10:46:51 GMT

Yeah, I see what you mean...I wonder if W3W could be incorporated into a DGGS?

Re: What does the DGGS mean?

Oliver_Burdekin — Thu, 26 Oct 2017 10:50:31 GMT

Hexagons and squares = apples and oranges? But that said this has partly been born out of raster / vector interoperability. I wonder how fine the finest hexagons are?

Re: What does the DGGS mean?

SimonKettle — Thu, 26 Oct 2017 10:59:36 GMT

Apparently, it is independent of scale...however I think there might be limits in a practical sense.

Re: What does the DGGS mean?

Oliver_Burdekin — Thu, 26 Oct 2017 11:05:49 GMT

From this site:

OGC 15-104r5: AS Topic 21: DGGS

A DGGS can even be designed for lossless encoding of vector geometry such that cells, and their integer addressing, predictably converge to the Real number coordinate pairs of each observation with each successive refinement – an essential property of a conventional coordinate system.

Swiftly followed by:
Reducing the reliance on an intermediary integrator or analyst is a key requirement for distributed participatory digital-Earth information systems.

Eeek, also a key revenue stream

Re: What does the DGGS mean?

PerryPeterson — Thu, 26 Oct 2017 19:02:50 GMT

The use case for the design and adoption of DGGS is straightforward – DGGS simplify the spatial analysis process. I think we can recognize that end-use decision-makers - from scientists to citizens - remain largely disconnected from spatial analysis. While lots of spatial data is available, it is not in a form that can readily answer their pressing spatial questions. DGGS solves the challenges of spatial data integration/fusion – a bottleneck in the current spatial analysis workflow.

Re: What does the DGGS mean?

PerryPeterson — Thu, 26 Oct 2017 19:08:23 GMT

I would not be overly concerned about revenue streams - adoption of DGGS should facilitate a rapid growth in the use of the spatial data that is being produced by GIS professionals. In other words, a discrete global grid system does not produce data anymore than an excel spreadsheet produces data. A DGGS is just the data structure for assembling and using data values.

Re: What does the DGGS mean?

PerryPeterson — Thu, 26 Oct 2017 19:17:12 GMT

DGGS can be any regular tiles - while squares are hard to accomplish on a sphere they are the familiar, triangles are fast, but hexagons are are the finest fit and therefore best for sampling data values.

DGGS are suppose to have infinite refinement though practically on 64 bit trig the cells are limited to 10 microns or so.

W3W is primarily an addressing scheme on a single resolution not equal area grid. A W3W type application on a DGGS would be a great idea as it would provide for both data integration and simple addressing.

Re: What does the DGGS mean?

PerryPeterson — Thu, 26 Oct 2017 19:27:28 GMT

Great insight Dan. While DGGS provide improvements to multi source data analysis with the assumption that data represents character of an area - Questions like Where is condition A and B and 4 kms from C but not D? or What is here within this adhoc polygon crossing several boundaries? - questions that rely on points like navigation and distance are still better on a continuous datum or projection. In many ways this is the Vector vs Raster argument though a well built DGGS harmonizes both data structures.

Re: What does the DGGS mean?

AndrewZolnai — Sun, 29 Oct 2017 07:35:33 GMT

(also on LinkedIn GIS group) see my AGI Lightning talk this past week (private link until released) https://www.slideshare.net/secret/fNxw0VQU099ObX