PRMS Weasel Overview

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Detailed Description

Presents overview of the USGS GIS Weasel software.


Date Taken:

Length: 00:06:09

Location Taken: Lakewood, CO, US


Roland Viger: Hello my name is Roland Viger.

I’m with the Modeling of Watershed Systems
Project and I’m going to talk to you briefly

about the GIS Weasel.

Which is a preprocessor, largely, for deriving
maps of features and parameters for use with

PRMS or really a number of other kinds of
models, watershed models.

This presentation is meant to be viewed in
conjunction with a separate recording which

actually shows a demonstration of the GIS
Weasel software.

Here is the homepage to get the software.

It’s been around for really over 15 years
by now so it’s pretty mature.

There’s a big document describing not only
how to use it, but there is an appendix which

helps you understand how parameters are derived
and especially if you want to use the GIS

Weasel to set up models other than PRMS, it’s
pretty helpful to see the exact methodology

and decide whether those techniques are actually
appropriate for that other model.

Because this is a long standing piece of software,
the technology on which it is built is now

a little bit dated.

It’s still fully functional, totally accurate
and useful, but it relies on Workstation ArcInfo

and it uses the Grid raster processing software
module underneath Workstation.

So, when I say “Workstation”, I put a
little screen grab, this is pretty simple,

but I really want users to see this.

If they don’t have the ability to call up
this kind of window on their computer, then

they probably don’t have Workstation ArcInfo.

When I say ArcInfo or ArcGIS, I’m not referring
to Desktop, which is the newer, more modern

incarnation of what we think of with ArcGIS.

This software is great, but it is not what
the GIS Weasel is built on top of.

So you need to have that Workstation software.

The good news is that if you do have a desktop
license, and that software running on your

computer, you’ve actually purchased the
license for the Workstation software.

Some system administrators are just choosing
not to install the Workstation software, but

they can get it, they’ve paid for it, they
are allowed to have it and they are allowed

to install it.

That shouldn’t be too big a deal.

So, for what it’s worth, ArcInfo is up to
10.2, soon to be 10.3, in terms of the version

number and Workstation was frozen at 9.3 and
that works just fine and that’s what we

use across the U.S. Geological Survey.

We don’t provide support on how to set all
of that up.

You just need to talk to your own system administrators,
or if you do your own administration, then

you need to take care of that.

Again, we’re built on top of Workstation
and it uses the Arc Marco Language which is

the scripting language for that platform and
it’s pretty much self-contained.

It doesn’t require anything like registry
edits on windows or compiling or anything

like that.

You just download it and open it up.

There is some installation instructions on
the web site which help you tweak the properties

for the short cut that makes it even easier
to start that software.

Please read those in case you get any hiccups
during the install process.

Other requirements are a digital elevation
model, it’s a pretty lightweight requirements.

This is because it is ArcInfo Workstation
you need it to be in a grid format, so it

cannot use some of the more modern ones, such
as Geotiff.

It is strongly recommended that you project
your digital elevation model into something

like an equal area projection.

So don’t use lat/long as your coordinate
system and even an equal angle projection

is not recommended.

Mostly because when you do things like calculate
the areas of your features like a hydrologic

response unit you want a projection that will
give you accurate numbers.

That’s really the only required input data

During the setup part of the GIS Weasel, you
will be asked to define the basin or area

of interest and you can have a preexisting
outline, in fact, we almost discourage that.

You’re really recommended to just be able
to define the outlet point and let the software

find the contributing area based on analysis
of the DEM.

Another requirement is the Data Bin.

In terms of delineation of your features,
by and large, most folks rely on the digital

elevation model almost exclusively.

Not a requirement, if you want to delineate
on the basis of some other ancillary data,

then you need to show up with those data available.

And, again, those should be in an ArcInfo
grid format and they should be in the same

coordinate system as the digital elevation

By and large, the Data Bin could be used for
this, but the Data Bin is specifically engineered

for helping to derive a standard set of parameters,
specifically oriented towards the PRMS watershed


So, these are the kinds of layer that we have
in the Data Bin.

We’ll show you a little bit later on a schematic
of what that should look like.

If you can’t quite get everything you need
off of the screen grab in this powerpoint,

it’s definitely straight from the GIS Weasel
users’ manual.

So you can go back and refer to that.

Another key, if you need to build your own
Data Bin is that when you download the GIS

Weasel, there is a Data Bin in there and this
is just for a little sample watershed, but

you can look at the structure and naming conventions
of all the contents in there and just mimic

that in terms of recreating your own Data

This is the general structure where you’ve
got ArcInfo workspaces, essentially directories

in red.

You’ve got your ArcInfo grids in the blue
boxes and then the yellow tables are the info

tables inside of that workspace.

You see the code schemes associated with the
grids in these different layers.

So, more detail on this is provided in the
GIS Weasel users’ manual and you can look

there for definitions.