dontgetwett
Tourist
Reged: 07/26/07
Posts: 5
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(removed the test version of the kmz file on Nov 30, 2007)
The (US) Federal Emergency Management Agency (FEMA) National Flood Hazard Layer contains Digital Flood Insurance Rate Map (DFIRM) data. New data are being added continually. Status information is shown at high and medium "eye altitudes;" full detail is displayed at an altitude of 15,000 feet or so.
Data are being provided through a web map service (WMS). The service has several data overlays, all of which are turned on in this example.
The service is available through http://hazards.fema.gov/wmsconnector/wms...amp;SERVICE=WMS (URL updated Sep 10, 2008) By using this link you can add the service to Google Earth and control the overlays that are displayed. For instructions see "Placing WMS Image Overlays" at http://earth.google.com/userguide/v4/ug_imageoverlays.html
This service was not designed with Google Earth in mind, and we are interested in your thoughts about the usefulness of this service in Google Earth (what works and what doesn't) and how you would use the service in Google Earth (types of activites and previous experience with FEMA's DFIRM data). Send your comments to "dontgetwett@gmail.com" (note two t's at the end!).
In addition to display through this service, these data (as well as other data for much of the rest of the United States) are available for viewing and downloading from the FEMA Map Service Center at http://msc.fema.gov
Edited by dontgetwett (09/10/08 08:04 AM)
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TalonDancer
Tourist
Reged: 07/31/07
Posts: 2
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First, many thanks for posting a link to the FEMA data that is dramatically more usable than FEMA's MSC Viewer:) It even works fairly well over a satellite internet connection (AKA the last resort for bandwidth in the boonies). The 'seamlessness' of the data is very welcome for those of us with property that spans a FEMA FIRM map boundary.
Unfortunately this link also makes it very easy to see the small spatial flaws in the FEMA FIRM maps when compared to aerial photo montages (e.g. Google earth). For example, creek centerlines that do not stay within a creek's normal channel; flood hazard zones that do not encompass the full width of damed sections of a creek; and flood hazard zones that wander up onto hill sides near creeks.
At first I thought these small spatial flaws were due to spatial errors in Google Earth's aerial image montage. But nearly identical spatial flaws are visible via FEMA's own MSC Viewer. On our property these spatial errors are on the order of 50'-100'. This is a really good fit for a 'national' data set. But if taken literally could unnecessarily restrict building on one side of a creek (or river), while allowing much riskier construction on the other side.
It would help if the FEMA overlays included "landmarks" that are easily recognized in an aerial photo montage (e.g. road intersections). This would allow people to better judge the spatial fit to the land and make more informed decisions prior to building.
Talon Dancer
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Forkboy2
Cartographer
Reged: 07/16/05
Posts: 441
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This is great, but very hard to see the patterns of the lines when overlayed onto the aerial photos in Google Earth.
A Screen Overlay of the Legend would also be very helpful.
Matt
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Matt
Google Earth Library
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dontgetwett
Tourist
Reged: 07/26/07
Posts: 5
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(Removed the attachment on May 28, 2008. Find new versions of the application through FEMA's Map Service Center (MSC) at http://msc.fema.gov)
Thanks to the community for its thoughts on the test version of the kmz file for viewing FEMA's National Flood Hazard Layer.
We used your and others' comment to improve the file, which is attached (version 1.0). The main changes are:
1. User-selection of layers to display: Users can choose which layers of National Flood Hazard Layer data to display.
2. Organization of layers for display at high, medium, and low "altitudes" in Google Earth: The layers provide data useful for status maps at high altitudes, regional overviews of flood hazards at medium altitudes, and detailed flood hazard maps at low altitudes.
3. Documentation for each layer: The name of each layer is hyperlinked to provide a description of the layer, the map symbols used for the layer, and additional links to other FEMA web sites relevant to the layer. If a layer is turned on, clicking on the text below the name of the layer (text that starts with "Draws at…") zooms the view to a sample display of the layer. Any other layer that is turned on also will be displayed if appropriate for the altitude.
4. Flood hazard map overlay covers the Google Earth map: The flood map image now fills the whole map ("3D viewer") panel in Google Earth.
One comment to which we did not respond is the need to improve the legibility of the labels. We plan to address that in the next release, currently anticipated for mid-February.
Edited by dontgetwett (05/28/08 08:16 AM)
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dontgetwett
Tourist
Reged: 07/26/07
Posts: 5
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New versions of this application are available through FEMA's Map Service Center (MSC) at http://msc.fema.gov. Look for the link to the Google Earth applications (there now are two) under the heading "National Flood Hazard Layer" or "NFHL."
For those of you who have been using version 1 of the "FEMA NFHL" application and have been experiencing the "big red 'X'", please accept our apologies. We inadvertently broke the application while updating a supporting service.
We anticipate fixing the underlying service in the next few weeks. In the meantime, consider upgrading to version 2.1 of the application (available through the MSC at http://msc.fema.gov) or turning off the floodways layer to remove the "big red 'X'".
Edited by dontgetwett (09/11/08 07:52 AM)
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Seasprite_FL
First Post
Reged: 09/05/08
Posts: 1
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Quote:
New versions of this application are available through FEMA's Map Service Center (MSC) at http://msc.fema.gov. Look for the link to the Google Earth applications (there now are two) under the heading "National Flood Hazard Layer" or "NFHL."
For those of you who have been using version 1 of the "FEMA NFHL" application and have been experiencing the "big red 'X'", please accept our apologies. We inadvertently broke the application while updating a supporting service.
We anticipate fixing the underlying service in the next few weeks. In the meantime, consider upgrading to version 2.1 of the application (available through the MSC at http://msc.fema.gov) or turning off the floodways layer to remove the "big red 'X'".
Just a corrected link to the above URLs, without an ending period or paranthesis - for those that don't want to have to figure out why links didn't work.
FEMA Mapping Service Center
On right side column look for link: Use Map Service in Google Earth
Good luck - and thanks FEMA, it has been very useful so far. 
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dontgetwett
Tourist
Reged: 07/26/07
Posts: 5
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This note is to persons who use early versions of the "FEMA NFHL" kmz file (versions 0.1, 1.0, and 1.1) that were distributed through the Google Earth Community. These versions show flood hazard areas with blue map symbols.
FEMA will turn off its "flood" map service that underlies these versions of the application in November 2008.
To avoid a break in service, please upgrade to the new version of the "FEMA NFHL" kmz file. The file is available in the NFHL section of the FEMA Map Service Center web page at http://msc.fema.gov
If the flood hazard areas are shown in red in the FEMA NFHL application you use (version 2.0 and later), you do not need to upgrade (although it's always a good idea to keep current).
This change applies to any application that uses FEMA's "flood" Web Map Service. If you created your own Google Earth application that uses the "flood" service, please change the application to use FEMA's "NFHL" Web Map Service. Information about the NFHL service also is available at the FEMA Map Service Center.
FEMA will modify the status map layers in the "flood" service to remind users of the need to change.
Thanks for your interest in this activity.
(And thanks to seasprite_fl for catching the URL problem on my previous note.)
Edited by dontgetwett (09/10/08 07:48 AM)
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