Reference data

[klongleywood]

@dhakelila The first reference dataset we can bring in is here -- global intertidal wetland change https://developers.google.com/earth-engine/datasets/catalog/UQ_murray_Intertidal_v1_1_global_intertidal

@lhilarides - can you identify the correct tidal flats layer to use?

Salt marsh data is still being finalized, and I will look in to the best coral reef layer to use.

[dhakelila]

Can you complete the full list of reference layers?:

• global intertidal wetland change
• tidal flats
• Salt marsh data
• coral reef

[klongleywood]

@dhakelila - these are the ones that that team identified as top priority. I don't think we'll be asking for others.

[lhilarides]

Coral reefs (Allen Coral Atlas) is in Earth Engine apparently: https://developers.google.com/earth-engine/datasets/catalog/ACA_reef_habitat_v2_0#bands

[klongleywood]

I reached out to a contact from ASU about making sure we get appropriate permission to incorporate Allen Coral Atlas data onto the site. They also have info about accessing the web services and API here: https://allencoralatlas.org/resources/

[lhilarides]

The coral atlas dataset has a creative commons license (same as GMW data, i.e. CC-BY-4.0). The citations guidelines from your link seem to provide all of the info we need. I suggest we start simple by just displaying a binary reef/non-reef map (reef_mask band)

[lhilarides]

Intertidal wetland change dataset: https://developers.google.com/earth-engine/datasets/catalog/JCU_Murray_GIC_global_tidal_wetland_change_2019

Again, a similar CC-BY-4.0 license

[lhilarides]

Version 1.2 of Nick Murrays Global Intertidal Flats (which includes the 2017 - 2019 period) can be downloaded here: https://ndownloader.figstatic.com/files/34337744 . It's > 52GB, so would be better if we can find somekind of API or WMS/WMTS

I am wondering why this has not been made available via Earth Engine like version 1.1 (which is a lot easier to find and use) and have contacted Nick about this

[klongleywood]

The coral atlas dataset has a creative commons license (same as GMW data, i.e. CC-BY-4.0). The citations guidelines from your link seem to provide all of the info we need. I suggest we start simple by just displaying a binary reef/non-reef map (reef_mask band)

Ye, we have confirmation that we can use the GEE version of this. We just need to run the attribution by the Allen Coral Atlas team before it's published.

[lhilarides]

Version 1.2 of Nick Murrays Global Intertidal Flats (which includes the 2017 - 2019 period) can be downloaded here: https://ndownloader.figstatic.com/files/34337744 . It's > 52GB, so would be better if we can find somekind of API or WMS/WMTS

I am wondering why this has not been made available via Earth Engine like version 1.1 (which is a lot easier to find and use) and have contacted Nick about this

Here's the link to the Earth Engine version of the version 1.2 intertidal extent (global_intertidal_20172019_v1_2): https://code.earthengine.google.com/8cd518882d418f07b129826f7832a7b8?asset=projects%2FUQ_intertidal%2Fglobal_intertidal_v1_2%2FL5_final_masked

[AngelArcones]

@lhilarides @klongleywood we (@larranz-vizz and I) have been exploring options for the colours of these layers. I'll show some screenshots, please keep in ming that the basemaps are from GEE, not exactly the same we have on the platform, but overall look is meant to work on the final form in the page (especially considering the different satellite map, the yellow polygons layer for locations...). I'll attach screenshots for each layer separately to further comment about each one.

[AngelArcones]

Intertidal flats gain and loss The idea here is to show an intuitive green/red layer to show gain/loss.

[AngelArcones]

Coral reefs: Here we suggest a coral-ish color that is bright enough to be noticeable from low zoom levels (in many areas corals appear as sparse patches from far), and works well with both light and dark backgrounds

[AngelArcones]

Intertidal flats: Here we have different options. One is going for a bright-brown colour, more visually linked to sand/earth in the context of intertidal areas. The potential disadvantage would be its visibility against some areas of satellite images such as deserts or brown rock. The other would be a shade of pink (I guess), which works better against all backgrounds (basemaps), but it's less visually connected to to what it represents.

[AngelArcones]

@lhilarides @klongleywood We would love to have your feedback on any suggestions / preferences as soon as possible, as we need to define the final colors before preparing the final format and exporting it to Google Cloud (which is a time-consuming process). Let us know with any comment you may have or if you want more/different examples (cc @ @larranz-vizz)

[dhakelila]

@lhilarides , @klongleywood , as the processing takes some time, we are going to start processing the layers with the proposed colors, and if later we need to adapt them, we'll do it.

[klongleywood]

@AngelArcones on the intertidal flats gain/loss -- two concerns -- would this be confusing to look at against the mangrove gain and loss layer? And this applies to the mangrove gain/loss layers as well, we do have concerns about this not being visible to people with red/green color blindness. Can we come up with an alternative for showing this that follows good design principles?

Corals look good, and we prefer the brown color for the intertidal flats in general but could you post some images of what this would look like zoomed in against the mangrove extent? This is how most people would use it.

[AngelArcones]

Hi @klongleywood, regarding your concerns:

• It is true that the gain/loss intertidal layer using a green/red color system could mix up with the Magrove gain/loss. We will explore other options that are intuitive enough for the user to quickly identify what it's seeing, but also with proper visibility. In terms of color blind perception, Lidia did some tests with those colors, and as you can see in the attached screenshot, there should always be a difference in the tone between them:

For the intertidal areas combined with the mangrove extent, I share a couple of screenshots of how both layers would (likely) look when used together. The image show mangrove extent place on top of intertidal areas

[klongleywood]

@AngelArcones ok, thanks for this update. Let me review with the team on Friday but overall I think this looks good!

[klongleywood]

@AngelArcones - this looks good -- thanks!

[klongleywood]

@AngelArcones and FYI @dhakelila -- can you make the title of the reef reference data Allen Coral Atlas and add the following attribution in the info button? Allen Coral Atlas (2020). Imagery, maps and monitoring of the world's tropical coral reefs. Zenodo. doi:10.5281/zenodo.3833242

[klongleywood]

@AngelArcones and fyi @dhakelila -- this morning @lhilarides realized we never sent you the salt marsh data. It can be accessed via a google earth engine app here: https://tomworthington81.users.earthengine.app/view/global-tidal-marsh-distribution

Do you need this in a different format?

[lhilarides]

TIDAL FLATS

• layer description: A high-resolution global map of tidal flat ecosystems for the year 2019.
• info button text: A globally consistent, spatially-explicit dataset with the occurrence of tidal flats, defined as sand, rock or mud flats that undergo regular tidal inundation. Original data has the years 1984 - 2019 available.
• info button hyperlink 1: Scientific paper: https://dx.doi.org/10.1038/s41597-022-01635-5
• info button hyperlink 2: Download: https://www.intertidal.app/download
• info button hyperlink 3: Data usage guidance: https://www.intertidal.app/about

[lhilarides]

GLOBAL INTERTIDAL WETLAND CHANGE

• layer description: Simultaneous detection of change in mangrove, tidal flat and saltmarsh ecosystems. Change product depicting loss and gain of tidal wetlands over the period 1999-2019. Global extent at 30-m resolution.

• info button text: Global Intertidal Change is a long-running collaborative project to develop high-resolution maps of Earth's intertidal environments and their recent change. Our overarching aim is to develop free, high-quality spatial data products that support the conservation and management of the world's rapidly changing coastal ecosystems.

• info button hyperlink 1: Scientific paper: https://doi.org/10.1126/science.abm9583

• info button hyperlink 2: Download: https://developers.google.com/earth-engine/datasets/catalog/JCU_Murray_GIC_global_tidal_wetland_change_2019

• info button hyperlink 3: Data usage guidance: https://www.globalintertidalchange.org/data-usage

• info button hyperlink 4: More information: https://www.globalecologylab.org

[klongleywood]

FYI @dhakelila for Allen Coral Atlas please use the following language:

On the main widget screen: This layer depicts the Allen Coral Atlas’s benthic classes and geomorphic zones that account for the world’s tropical shallow coral reefs at 5 m resolution. For more information, visit AllenCoralAtlas.org.

---

More info:

Overview: This layer depicts the Allen Coral Atlas’s benthic classes and geomorphic zones that account for world’s tropical shallow coral reefs at 5 m resolution. More detailed information on coral reef habitat mapping and dynamic threat monitoring can be found at www.allencoralatlas.org. The Allen Coral Atlas is led by Arizona State University and developed in partnership with a consortium of coral reef experts to provide actionable data and a shared understanding of coastal ecosystems to communities, practitioners, and decision makers worldwide. More information on the methods developed for both the benthic and geomorphic maps, as well as the monitoring system and auxiliary datasets, can be found at the Atlas’s Science and Methods page. © 2018-2023 Allen Coral Atlas Partnership and Arizona State University Date of content: 2021 License: CC-BY 4.0

[AngelArcones]

@klongleywood For the salt marshes data, would it be possible to get the address of the GEE asset (as in the other maps)?

[klongleywood]

https://tomworthington81.users.earthengine.app/view/global-tidal-marsh-distribution and GEE Asset ID is Asset ID: users/tomworthington81/SM_Global_2020/global_export_v2_6/saltmarsh_v2_6

[AngelArcones]

@klongleywood Here's a color proposal for the salt marshes map. I'm sharing them with the satellite basemap, because it seems like it is the option that would be best for the user to contextualize (under flat maps, the salt marshes sometimes appear to be in the sea, when in reality it's intertidal / shallow waters), and also because it is the option where visibility could be most challenging (clear and dark basemaps are less problematic). Also, I've included the mangrove extent layer (on its original colour) to better compare how it would look like.

[AngelArcones]

@klongleywood Update on this: the layer is available in staging for review, let us know if you have any feedback or identify any needed changes.

[klongleywood]

@AngelArcones sorry for the delay -- I just had a look at this and at the zoomed out scales, the layer is really over-generalized with many spots exaggerated and some areas not visible at all. Is it possible to refine this at all?

[AngelArcones]

Hello @klongleywood, I've made some changes in order to produce a better view from low zoom levels. Although some areas still look more densely represented (e.g North Sea and Baltic Sea), visibility is now more balanced for all regions and better displays the (more sparse) data in the mangrove areas from far. Let me know if you think this view works well.

[klongleywood]

Hi @AngelArcones -- it looks better for sure. If there's any way to make it look a little less dense at the zoomed out scale, it would be helpful to not over represent the habitat.

I looked at this with Tom (data provider) today and there are still a few issues with how it looks at various scales.

At a mid-range zoom in, the blockiness/density looks very odd as in the image below -- possible to switch to a higher res tile at a higher zoom scale?

When zoomed in close, it also looks a bit blurry zoomed in compared to the source data (compare below). Any way to change this? We also noticed that it is an issue with the tidal flats data.

[AngelArcones]

Hey @klongleywood I've made some refinements to improve visibility at intermediate zoom levels for the salt marshes, and it should have a better look at zoom level 4 (the zoom at which you provided the example, and where it now changes to finer detail). I think this is something that other layers can benefit from, but depending on each dataset the needs for visibility would change, so I'll review them but please let me know if you see the need for this kind of changes in the other contextual layers.

On the max zoom level, the blurriness is because the tiles for contextual layers are generated at a maximum of zoom level 12 (which is this view aprox.), so beyond that there is a loss in sharpness in the edges of the pixels during rendering. While we could potentially generate tiles for further zoom levels, it gets increasingly costly (exponentially) in terms of computation and storage for each level, which is why we decided to generate "only" up to zoom 12 for these. We can discuss cost and benefits if further refinement is required.

[klongleywood]

@AngelArcones -- much better, thank you! We're happy to have this go to production when ready.