[GRASS-user] Trento3D screenshots redone

[Thomas Adams]

Hamish & Markus,

How did you do the inundation? With r.lake; does this use a level 
surface? If so, this is not correct for a river, due to the downstream 
slope of the topography and the hydrodynamics of the flow. The resulting 
water surface elevations would be less than a level surface. Channel & 
overbank cross-sections are needed (corresponding to those used in a 
dynamic flow model) which then need to be intersected with the 
topography. The US Army Corps of Engineers HEC-RAS & HEC-GeoRAS software 
that is integrated with ArcGIS does this correctly.

This is very exciting to see. I am on a National Team within the U.S. 
NOAA, National Weather Service (NWS) to study and make recommendations 
on the direction that should be taken with meeting our GIS needs (which 
is considerable), particularly in the area of operational hydrology, 
that is, river and flood forecasting. GRASS is **very much** an option. 
One of the main reasons for the viability of GRASS is that ESRI does not 
support Linux, which is our operational OS. We operate our 
computers/models behind a very restrictive firewall. While it is 
possible to have Windows-based PCs within our operational network (and 
we do), they are poorly integrated with our Linux-based workflow. 
Consequently, as far as GIS is concerned, we are somewhat stuck between 
2 worlds: Linux & MS-Windows. There are some things ArcGIS can do that 
we are unable to do in GRASS. My previous paragraph mentions one of 
them. This is a huge issue for us. So, the more examples I have of GRASS 
meeting NWS needs, the better.

I have GRASS installed on our operational systems and I use it both 
interactively for various analyses (mostly involving precipitation & 
temperature) and in batch mode with some scripts I have written. We have 
13 River Forecast Centers and 125 Weather Forecast Office across the US. 
The possibility exists for GRASS to be used in all these offices and our 
National Centers. I'm not being boastful here, but through my 
persistence and "educating" people on GRASS, some River Forecast 
Centers, one National Center (the Hydometeorological Prediction Center), 
and the NWS Hydrology Lab. have started using GRASS. This is a big step, 
because within the NWS, *many* very talented programmers exist who would 
be itching to contribute to GRASS development if the decision were made 
to formally adopt GRASS for GIS use. Already, i addition to the use of 
Linux, the entire NWS recently made the switch to PostgreSQL from 
INFORMIX. The NWS is fully committed to open source software (there are 
many using R as well).

Regards,
Tom

Hamish wrote:
>> - interpolate dem to highres (I used 2m pixels) with r.surf.rst
>>     
>
> is this really needed? g.region res=2 & NVIZ will smooth (or do you see
> flat patches/aliasing grid then?).
>
>
>   
>>> If not, is it possible to use the Trento dataset to create one? One
>>> possible use if other details can be worked out is to create
>>> maps of flood inundation to show buildings affected by flooding. 
>>>       
>
> Yes! worldwide problem of all coastal & riverside cities. Trillions of
> dollars at risk. ([ed.] compare with the cost of dealing with CO2 issues
> now) This sort of thing (esp. animated) is very effective for
> presenting dry model results to the public & policy makers.
>
>
>   
>> OK, I couldn't resist :-)
>>
>>  http://mpa.itc.it/markus/grass61/demos/rlake/
>>  -> see at bottom for new screenshot with flooding
>>     (needs r.lake which is still not in CVS...)
>>
>>     
>>> I understand one must have the 
>>> building data (how was *that* obtained?).
>>>       
>> The Trento municipality was going out and digitizing all builings.
>> Another option is to digitize building footprints from orthophoto
>> (v.digit) and assign a typical height to each building.
>>     
>
> trick: You don't need actual height of buildings, just number of floors.
> (how you did Trento version 1 Markus?)
> Interns can do orthophoto tracing work :)  .. LIDAR ..
>
>   
>>> This type of presentation is 
>>> very effective in capturing the imagination (as it were) of those 
>>> possibly affected by flooding.
>>>       
>> Fully agreed and done. Except for r.lake everything is in
>> 6.1-CVS.
>>
>> Only the merge of the flood map with orthophoto could be better
>> (r.mapcalc will kill the color table, r.patch as well). In February
>> I did a trick in nviz (see earlier flood screenshots) which I
>> don't remember today (maybe I loaded the DEM twice or so).
>>     
>
> Loaded r.lake surface as a second raster?
>
> A trick: in NVIZ make a New constant surface of 0.0, set color to
> something white-blue, set transparancy to ~1/2, and raise-lower level
> with "Position" button's z-slider. I never seem to get surface order
> correct, "Draw Current" is your friend.
>
> e.g. sea level lowered to ice-age/old tectonic levels to show ancient
> shore line position:
>   http://bambi.otago.ac.nz/hamish/pics/sill_iceage_115m.jpg
>
>
> Get height from high-water mark of last 100yr flood? (surely recorded)
>
>
>
> Hamish
>   


-- 
Thomas E Adams
National Weather Service
Ohio River Forecast Center
1901 South State Route 134
Wilmington, OH 45177

EMAIL:	thomas.adams at noaa.gov

VOICE:	937-383-0528
FAX:	937-383-0033