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Visualization of storm surge – Unreal Engine real-time rendering (twitter.com)
35 points by isp 6 months ago | hide | past | web | favorite | 9 comments

This visualisation is a remarkably clear & effective way to communicate the (otherwise abstract) risk data.

From: https://twitter.com/itsren/status/1040313433978286082 - rendered real-time using Unreal Engine

I've been looking for a reason to overlay real time physics i.e. fluids in 3D GIS for a while, and here it is!

There's no reason bar processing demands that this couldn't be done for any arbitrary 3D GIS dataset - this example seems to be just a very small area constructed specifically for the video, whereas it would be possible to zoom into any area and view the effects. Not to take away from this video, because it is certainly compelling.

Do you think fluid simulation is advanced enough at this stage to simulate something like, "Assuming sea level rises 6 feet at the coast, this is how the surge will propagate across the landscape"?

Or will it be more like "If 6 feet of water is in this (fairly localized) area, this is how the local region will be affected"?

Possibly, though I imagine the complication there is getting a good enough base geometry to be happy with your simulation.

You could cut some corners by starting from the national floodplain data, which has a lot of engineering hours already in estimating the floodable area for a region, based on water height (and is what your area's flood insurance rates are based on).

I guess there are two types of modelling of interest in the video: firstly the modelling of where the water will go, and secondly the visualisation of how it would look at a particular location. For the modelling of where the water will go it's fairly simple and well-known at this point: you take a raster digital elevation model, where the value of each cell represents average elevation across the cell or in some cases elevation at the centre point of the cell, and then you effectively pour in water at your starting cell/cells, (which would be the coastline in this example) and let it propagate across the raster according to elevation. Some of the techniques are covered here: https://www.supermap.com/EN/online/Deskpro%206.0/SDTechTheme...

The limiting factor (as another poster has commented) is likely to be the resolution of the data available, as processing power is generally good enough these days to handle any reasonable scenario - the study area is limited to the area of the storm and adjacent areas, and there are few areas where there will be a comprehensive DEM available to e.g. sub-meter accuracy. With increasing availability of drone LIDAR data we may well get comprehensive data that pushes the boundaries of what we can do, and which will require generalisation to coarser resolution. I suppose when the effects of even a few inches of water can be so catastrophic in terms of insurance claims increased resolution could be extremely valuable. For example I know that insurance companies already have sophisticated models of risk where flood risk is just one of many layers of modelled risk that they combine to avoid having too much risk in any one area.

The second type of modelling is the 3D modelling seen in the video. With a good 3D GIS dataset as seen in e.g. Google Earth you could take the results of the analysis described above and use this to determine which areas will be affected by flooding. It would then be a case of adding a layer powered by fluid simulation with the other layers in the dataset set up as 3D entities around which the fluid must flow. The point is that once you had your data set up as well as your fluid modelling, you could zoom to any location and view the results in that location, and do this on the fly - whereas in the video it is almost certainly a one-off canned job for a single location.

She's very lucky that the storm surge avoided the spot where she was standing.

She applied a bubble spell before it all started.

I wonder what model predicted where she should stand.

Very cool usage of UE. It's such a fantastic engine. They're also making a big push into architecture visualization.

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