No subject
vieux at chief.ecn.uoknor.edu
vieux at chief.ecn.uoknor.edu
Mon May 10 23:03:58 EDT 1993
Activities here at the Environmental Modeling and GIS Lab--
1. What model are you using with GRASS?
We have written a C program that is an internally integrated
program using grass libraries to perform surface runoff modeling.
2. Which data structure is more suited to the process, Vector or Raster?
We have relied extensively on raster data structures for
manipulation, analysis, and storage of model parameters.
However, we extract finite element topology from the 8-directions
aspect map. The topology is used for assembly of the system of
equations that when solved, produces flow rates at every grid cell
in the watershed.
3. What tools need to be developed in order to make GRASS more useable for
hydrologic modeling?
We agree with others that cry for floating point binary maps. After
recoding soils maps into 5+ infiltration parameters we have more
multiplication factors to keep track of than we can stand.
My purposes in asking for efforts dealing with hydrologic model and GRASS
integration was
1) To see what people were doing with GRASS,
2) To see what future GRASS tools are needed, and
3) To see what the needs are in the GRASS user community for
integrated hydrologic models.
Some interesting patterns emerged from the survey. I have taken the liberty to
summarize comments and make observations.
-GRASS must be changed so that modelers can use floating point binary cell maps.
-Zeroes must be allowed rather than treated as null values (no data).
-How many times is SCS or others going to pay for an interface to AGNPS.
-Most people interface with models by preparing an input file for
execution by the model.
RESPONSES GATHERED TO DATE (10 May 1993)
____________________
From: cmiller at pnwg.wa.com (Craig Miller)
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Subject: Re: Hydrologic Modeling and GRASS
Status: RO
We are going to use GRASS to do modelling at the Chelan Co SCS, but we have
not selected a model yet. Could you forward me a compilation of responses
so that we might make a more informed selection? Even if you just
concatenate all the responses together I would really appreciate it.
Sincerely,
Craig A. Miller
cmiller at pnwg.wa.com
GIS Analyst
Chelan Co. SCS
____________________
From: riker at hydro1.geo.duke.edu (Dan Riker)
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Subject: Re: Hydrologic Modeling and GRASS
Status: RO
On the informal survey:
I am using GRASS to determine the ln(a/tanB) index for TOPMODEL, in which
raster format is more suitable. I think that a tutorial explaining all that
GRASS can do to manipulate catchments would be helpful. For what I am doing, I
feel that GRASS can accomplish most of what I need, although a simple
statistics module would be handy.
Dan Riker
Duke University
____________________
We are using the SPUR2 model in conjunction with GRASS. The primary purpose of
our simulations is to determine the effect of climate change on US grasslands
with special emphasis on plant and animal production. I wish there existed an
easy way to interface models with GRASS. Such an interface would deliver data
to and accept data from the simulation model. Also, a good Kriging and other
interpolation tools are necessary.
+---------------------------------------++---------------------------------+
| Dr. Jon D. Hanson || Comm: (303)490-8323 |
| USDA, Agricultural Research Service || Fax: (303)490-8310 |
| Great Plains Systems Research || jon at gpsrv1.gpsr.colostate.edu |
| 301 S. Howes, P.O. Box E || FTS2000: a03jonhanson |
| Fort Collins, Colorado 80522 || |
+---------------------------------------++---------------------------------+
____________________
Same here.
I would like to start interfacing a snowmelt model
(CRREL's SNTHERM) with a hydro model this summer.
Any info on models that are compatible with GRASS would
be appreciated.
____________________
>1. What model are you using with GRASS?
>
I am working on the integration of groundwaterflow models in GRASS.
I wrote in C a one layer regional groundwaterflow model as a GRASS program.
>2. Which data structure is more suited to the process, Vector or Raster?
>
The model uses GRASS raster maps as input (topography, pumping data, net precipitation and hydraulic conductivity values) and produces raster output maps like groundwaterlevel and distribution of infiltration and groundwater discharge areas.
>3. What tools need to be developed in order to make GRASS more useable for
> hydrologic modeling?
>
The main problem in the development for this program was the lack in GRASS
of foating point support. This makes simulations and storage of data very
cumbersome.
I hope that the floating point can be included in GRASS as soon as possible.
For the moment therefore, I prefer to work with a 3 layer groundwater model
beside the GRASS environment. The groundwater model also has a flow tracing
module. In this case GRASS is used as an input/output processor.
I also told this in my presentation at the European GRASS users meeting,
2/4/93 in Genova, Italy.
VVVVVVVVVVVVVVVVVVVVVVVUUUUUUUUUUUUUUUUUUUUUUUUUBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
Okke Batelaan email: batelaan at hydr1.vub.ac.be
Laboratory of Hydrology tel: x-32-2-6413021
Free University Brussels fax: x-32-2-6413022
Pleinlaan 2
1050 BRUSSELS, BELGIUM
HHHHHHHHHHYYYYYYYYYYYDDDDDDDDDDRRRRRRRROOOOOOOOOLLLLLLLLLOOOOOOOOOGGGGGYYYYYY
__________________
From: Brian Connelly <bac at u.washington.edu>
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Subject: Re: Hydrologic Modeling and GRASS
Status: R
1. We are using a physically based distributed hydrologic model
developed by a post-doc at the University of Washington named
Mark Wigmosta.
2. Raster
3. The watershed delineation program is terrible. It would be
nice if one could specify a gage location and be able to
delineate the watershed draining to that gage.
Sincerely,
Brian
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Brian Connelly
College of Forest Resources phone: (206) 543-5506
University of Washington AR-10 FAX: (206) 685-3091
Seattle, Washington 98195 e-mail: bac at hardy.u.washington.edu
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
__________________
From: JIM ZOLLWEG <H32X at VAX5.CIT.CORNELL.EDU>
Subject: hydrologic modeling
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Status: R
HI!
It's good to see you in the group. I've read several of your articles
(esp. using GIS for controlling data for FEA models).
I am using the raster side f GRASS to write original runoff models.
the process is very quick so I can experiment with lots
of ideas.
what I really need is some sort of floating point capability. its tough
and not always the correct thing t do to be always multiplying by a factor
and then dividing.
some sort of a control structure would be good to, such as repetition, and
choice.
thanks for taking a lead in this!!
Jim Zollweg
Ag+Bio engineering
Cornell University
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Subject: survey, hydrologic modeling
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Message-Id: <BEOQ5154B4E6B2 @ LUA6>
Status: R
I am responding to your survey about hydrologic modeling work with Grass
I am not sure if our work is exactly what you are interested in, but I t
hought I would respond. I am working with an interface of Grass and 4 w
ater quality models--AGNPS, EPIC, GLEAMS, and SWRRB. The interface is
aimed at automating the extraction of model parameters from Grass GIS
files, as well as a GUI for easier use of the models. The models are
all raster-based, so raster is the easier format. The modeling is being
used in conjunction with a 319 Clean Water Act project to address
non-point source pollution (primarily pesticides) in surface water
public drinking sources. The interface is being written by a contractor
and is being paid for by SCS. If you have any further questions, send
mail to me at cooke at lua6.lu.edu . Thanks Elizabeth Cook
------------------------------------------------------------------------
Elizabeth Cook
Mail: COOKE at LUA6
INTERNET: COOKE at LUA6.LU.EDU
VOICE: (314) 681-5153
FAX: (314) 681-5153
__________________
From: "S. E. Walker" <guernsey at holstein.age.uiuc.edu>
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Subject: Hydrologic Modeling & GRASS
Status: R
1) We are looking at both AGNPS and ANSWERS in
conjunction with GRASS4.0. I'd also like to
take a look at TOPMODEL.
2) Right now I'd say raster format is better,
but that opinion may change as I get further into this.
3) Useful tools might include the ability to use finer
grid resolution on some sections of the watershed.
Will let you know if I think of other things.
--Sharyl E. Walker
Dept. of Agricultural Engineering
University of Illinois
Urbana, IL
217-333-0945
guernsey at holstein.age.uiuc.edu
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From: srin at iiml.tamu.edu (Srin)
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Subject: Re: Hydrologic Modeling and GRASS
Status: R
X-Lines: 18
We have integrated Hydrlogic models such as AGNPS, ANSWERS and SWAT (Soil and
water Assessment tool, newer version of SWRRB and ROTO models) with GRASS.
When I say we (Srinivasan, Chris Rewerts, J.G. Arnold and B.A. Engel),
and I am sure you are familier with every one.
Further I am looking into to interface several other models including
some of EPA models like WASP, QUAL2E, and ARS model EPIC.
If you would like to hear more about the different aspects of this integration,
let me know.
Thanks.
Srinivasan
__________________
From: greg at towhee.cor2.epa.gov (Greg Koerper)
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Subject: Hydrologic Modeling and GRASS
Status: R
Speaking for the staff of the Corvallis Environmental Research Lab, I find
that GRASS is a valuable display device for modelling, but until floating
point data support is added, it has limited additional value for dynamic
modelling. Yes, you can kludge it, but the overhead is a pain. The inability
to distinquish zero from null data is a further problem.
I like GRASS, I encourage our unit to take advantage of its open architecture,
but for ecological modelling purposes its basic capabilities need extension.
greg
******************************************************************************
Greg Koerper Internet: greg at heart.cor.epa.gov
ManTech Environmental Technology, Inc. UUCP: hplabs!hp-pcd!orstcs!koerper
US EPA Environmental Research Lab
200 SW 35th St., JSB
Corvallis, OR 97333 "The 90s will make the 60s look like the 50s.
(503) 754-4490 Just ask your kids."
fax: (503) 754-4338
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<Address and delivery info deleted...sorry!>
I'm working on interfacing HEC-1F and HEC-2 into a flood
prediction system which uses GRASS. I'm using the f-tools
code contributed by Terri Betancourt.
I, too, would be interested in knowing the outcome of your
survey.
Karen Frederickson
USACERL
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