Posts tagged flood
I finally figures out what I was doing wrong and was now able to post the last three webinars to the website. These covered:
- Tabletop Exercises
- What’s new in Depiction version 1.4
- Water Simulation Elements
You can find them here.
Depiction & DepictionPrep both make use of Depiction’s simulation technology, letting you do rapid, basic simulations of various scenarios. The two programs do have some differences–DepictionPrep only includes disaster simulation elements, and the variables for many of those elements have been simplified. Both of them, though, provide the ability to quickly consider “what if” scenarios in your own neighborhood–or pretty much anywhere else.
Let’s go through the elements available. Several of these elements make use of elevation data, whether brought in directly from Depiction’s Quickstart sources, or loaded from other sources. The higher resolution the elevation data is, the more precise these simulations will be.
Flood: The ‘classic’ Depiction simulation element, the flood very simply calculates what the water level would look like if it were set to a certain height above the ground level at a particular point. This works basically the same way in both Depiction and DepictionPrep.
Runoff: This does a basic ‘path of least resistance’ simulation of water flowing downhill, and works best in sloped areas–if you’re simulating a flood in an area like this, the runoff tool is likely to provide better results than the flood simulation itself. The full version of Depiction provides several variables that can be tweaked to customize the simulation result. The flood also disables people, buildings and elements that it comes into contact with.
Antenna and Line of Sight: Both of these elements, only included in the full version of Depiction, use a line-of-sight simulation behavior, determining what areas can be seen from a certain point, based on the elevation data present. The elements use the same behavior, but have different default variables–height, field of view, direction, ‘horizontal sampling’ (which determines the precision of the simulation) and maximum distance–set to approximate different things. The antenna element also has additional fields that, while they don’t affect the simulation, are of interest to anyone dealing with antennas, such as frequency, power, etc.
Other simulation elements make use of the road network data obtained from OpenStreetMap.
Route – road network (called simply Route in DepictionPrep): This is a basic, ’shortest distance’ route to which you can add waypoints, which also provides turn-by-turn directions if the street names are listed in OpenStreetMap. Additional route types are available in the new Logistics Add-on. Where the road network simulations really shine, though, is in the way they work if the roads do not.
Road barrier and Water over roadway: These elements both disable any road network they touch, causing routes to recalculate and find the next shortest path between waypoints. You can change both the shape and size of these elements to set any region you want as off-limits. This is an enormously useful tool for determining evacuation routes, or just general routing that avoids a certain area.
Explosion: This element does the same basic thing–set a blast radius, and the explosion disables the road network in the area–but in addition, the explosion also disables various other elements unfortunate to be caught in it.
Fire perimeter: This freeform polygon basically enables you to create your own shape that disables elements within it. In DepictionPrep, it also disables road networks as explosions and road barriers do–in the full version, this ability is easily added from the interactions menu.
Plume: Finally, this element does a very basic simulation of a chemical plume, using variables like amount, wind speed, wind direction and amount of time. This generic plume element isn’t nearly so accurate as something like ALOHA modelling, but for the purpose of quick simulation or scenario building for family preparedness, the plume element is a great option.
For more on simulation elements watch this Depiction 101 video.
Silvia Estrada-Flores is a Depiction user and an expert in the food industry supply chain who lives in Australia. Naturally, she has been very concerned about the major flooding occurring in the state of Queensland–and, specifically, about the way the flooding is affecting grocery stores in the area.
Silvia used Depiction to first run rough simulations of the flooding and potential flooding in and around Brisbane, Queensland, using ASTER-GDEM elevation data (because she was unable to get access to the higher quality data generated by the government), and then to depict the situation facing the grocery stores in the area. She also used Depiction’s geoaligning capability to show the official flooding predictions in relation to grocery stores.
Silvia writes, “Today, I can just reassure consumers in Brisbane that there will be stores open around you. I am hoping that this map shows the areas where consumers can purchase supplies in these confusing times.” She will be writing more in the near future on the challenges of maintaining the supply chain in this situation, so pay attention to her blog, Chain of Events, if this information is important to you.
Even if you are not specifically concerned with the response of the food industry supply chain to disasters (though if you eat any food yourself, you may want to think on it at least a little!), I think Silva’s work illustrates a couple broader points. First, this is exactly the kind of thing Depiction was built for–giving powerful tools to subject-matter experts like Silvia, who may not have any experience with or access to GIS technology, but who have a need to depict the world around them in rapidly changing situations. Very few people have both the skills and resources to use high-end GIS and modelling software and the expert-level knowledge and experience in something like food industry supply chain management. And yet that field, and many others like it, have a real and abiding need for location-based knowledge, situational awareness, and the ability to ask “what if” about their community. We are very proud that Silvia was able to use Depiction to gain insights into the situation in Brisbane, and that Depiction users across the world are doing similar things within their own fields of expertise, without having to be mapping technology experts.
Second, the situation reminds us of the need for collaboration across boundaries. In her first blog post, Sylvia mentions her frustration with the unavailability of good quality elevation data:
It was difficult to find freely available information on elevation data. This can create difficulties for those planners dealing with emergency preparations that are not necessarily acting on behalf of the Government. I am aware of the National Elevation Data Framework portal, but I could not find elevation data for Queensland that is readily accessible. The process for downloading information (even in those cases where data happens to be free) is slow, due to the requirements of data licensing and so on. Not really useful when you are in a hurry to see flood damages and impact…
Here in the States, we are fortunate to have the USGS, which provides a relatively user-friendly method of obtaining good quality elevation data at multiple resolution levels through the Seamless Data Warehouse. This has allowed us to make US elevation data available as a Quickstart data set in Depiction. However, that is not the case in most parts of the world, and even here in the USA, many other crucial datasets are out of reach, depending on the locality. As Silvia notes, this presents major problems for people who are attempting to prepare for or respond to a disaster, among other things. Governments who are looking for an easy way to bolster the assistance that can be provided by the private sector during a disaster might think about making their GIS data easily accessible by the public.
With the advent of the Depiction Reader, we’re starting a new feature called “Depiction of the Week”. Each week we’ll feature a depiction that you can open with either the Reader or the full version of Depiction. Are you a Depiction user with a Depiction you’d like to see featured? Click here to submit it.
This week’s depiction is this Honolulu Tsunami simulation. This depiction was originally built back on February 27, 2010. That was the day when an 8.8 magnitude quake hit just off the coast of Chile, and a tsunami warning was issued for the entire Pacific. Hawaii underwent its first tsunami evacuation since 1994, and waves of 8 to 9 feet were predicted.
Fortunately, the waves ended up being far smaller than predicted, but there were tense hours when that was unclear. During those hours, I happened to be far away from the office and my usual computers. As it happened, I was at a wedding, with nothing but my wife’s netbook. Still, I wanted to use Depiction to quickly show what the potential impact of waves of different heights could be.
Fortunately, I was able to snag some time and some wifi, and created this post with links depictions of Hilo Bay, Honolulu, and, at the request of a commenter, Kahului Bay on Maui, each with simulations of 6, 9 and 12 foot inundations.
The depiction presented here is the one created for Honolulu, with a few more elements added–specifically schools, hospitals and evacuation zones, all retrieved from the very thorough Hawaii Statewide GIS program.
A few caveats: the Depiction flood model is a very simple one, built to give a rapid potential impact (even when just using a netbook!) by showing what an increase in water level from a certain point would look like, based on the elevation data contained in the Depiction. The elevation data I used was that provided through Depiction’s Quickstart feature, and is 30-meter DEM data from the USGS (this means that the elevation was measured every 30 meters). Using higher resolution elevation data–where the elevation was measured every 10 meters, for example–would likely give different, more accurate results, though it would also increase the file size.
Today we had a great Flood Safety Awareness Week webinar with Carol Dunn, and she mentioned several great resources for flood preparedness that we wanted to share here:
- FEMA’s “Repairing your Flooded Home” Resources
- National Weather Service flood resources
- Floodproofing methods from LSU
- So you live behind a levee
- 2resilience.org’s Flood Preparedness Workbook (pdf)
- 2resilience.org’s GIS resources
- Fargo’s flood info center
- Mezzoman “Meet in the Middle”
And there’s also the Depiction Preparedness Add-on Pack, which Mike demoed at the end of the webinar, and which adds over 30 new elements to help create emergency plans, as well as new Quickstart data sources with information about past disasters.
You can also download video of the webinar. We have streaming video up now as well. (Note–Carol would like to clarify that, though she was described as a shelter manager, she was actually a shelter supervisor, which is different.)
Fortunately, the tsunami that hit Hawaii was nothing like what was feared. The experience did provide an opportunity, though, to demonstrate how easily Depiction’s flood element can simulate things like tsunami inundation and storm surges. It’s one example of a very simple but powerful tool that Depiction has–just drop a flood in the water body, input your total feet, and Depiction will calculate the extent based on the elevation data. I just used the basic 30-meter data Depiction pulls in through a quickstart, but any data type will work, and you can get higher resolution data for much of the US, at least, from the USGS Seamless website.
The story behind my post yesterday is also moderately interesting–I was out of the house all day, at a wedding and running various other errands. The only computer I had access to was a $300 netbook that had never run Depiction. I wasn’t quite sure it would work, but once I got it installed it ran beautifully, even on 1GB of RAM.
Kim Buike also put together a short little video that demonstrates a bit more of how Depiction’s flood model can be used in tsunami simulation:
The QST article by Depiction user David Friedman, KE7GOY, is now available for download as a PDF. David has used Depiction to do some pretty remarkable things, some of which he describes in the article. Here’s how it kicks off:
In the winter of 2008, the Snohomish County (Western Washington) Department of Emergency Management declared a wide- spread flood emergency. The organization I am involved with, MuttShack Animal Rescue and Response, was activated and I became its Disaster Response Director. There was a problem, though: I was in New Orleans on vacation, more than a thousand miles away. Despite the distance, I was still able to fulfill my role thanks to Amateur Radio, the Internet and a software application for Windows named Depiction.
Using Depiction to create and display floods requires having elevation data. The elevation data available through Depiction’s Quickstart resource list is from the United States Geological Survey (USGS) – it is their default “30 meter resolution” – in other words, every 100 feet or so, it measures the height of the terrain. In general, this is good enough for big picture stuff.
For community or neighborhood level flood depictions, higher resolution elevation data works much better. You can access 10 meter elevation data from the USGS NED (National Elevation Dataset) site at http://seamless.usgs.gov/index.php though the process is bit cumbersome. Fortunately, there are other sites where publicly accessible 10 meter DEM (Digital Elevation Model) data can be found, easily downloaded to your computer and imported into your depiction. More >