Computer Terrain Mapping, Inc.
2005
Alpine Loop Visual Resources
map
The Alpine Loop Visual Resources data set shows the distribution of
important viewsheds and visually significant skyline regions from a
number of roadways in the study area. This data set is used to determine
the Conservation Resource Value.
The visual resource mapping combined two separate analyses:
important viewsheds and visually significant skyline regions.
This data set shows the combined visual resource map. The viewshed
algorithm assesses the visibility of a structure on the
landscape disregarding trees, intervening buildings and other
non-topographic obstructions. The skyline utility checks for
visibility of a structure above the physical skyline.
The Alpine Loop Spatial Analysis and Mapping Project inventoried
natural and cultural resources and identified important areas where
overlapping resources occur. The results from this project will
provide an opportunity for area stakeholders - landowners, outdoor
enthusiasts, surrounding communities, federal government agencies
and local and national preservation groups - to come together to
find solutions that maintain the Alpine Loop experience for future
visitors and residents, while working within the framework of
landowner objectives as well as local and federal government goals.
The Alpine Loop Spatial Analysis and Mapping Project analyzed the
Alpine Loop landscape, considering important natural and cultural
resources along with the likelihood of development based upon
building constraints. The Project aims to provide a planning tool
for area stakeholders as they consider the variety of land
management options and the future of this magnificent region. The
next logical step will be to craft solutions that work within the
framework of landowner desires, local and federal government land
management goals, and available financial and technical resources
to manage the area in a way that preserves the Alpine Loop
experience for future generations.
While the Alpine Loop lies within three counties - San Juan,
Hinsdale and Ouray - the analytical work extended into a portion
of San Miguel County. The resulting mapping and analyses will:
1. Create a spatial foundation to aid future projects in the
Alpine Loop corridor;
2. Serve as a prioritization tool for evaluating the
conservation potential of individual private parcels;
3. Provide the necessary framework for pursuing future
funding opportunities.
2003
2005
Data were retrieved from various sources and analyzed between 2003
and 2005. See Data Quality Information for time information for
source data.
None Planned
-107.8725478
-107.2256611
38.08819806
37.73515861
None
Conservation
Resources
Visual
None
United States
North America
Colorado
San Juan Mountains
Ouray County
San Juan County
Hinsdale County
San Miguel County
Ouray
Silverton
Lake City
None
None.
Computer Terrain Mapping, Inc.
Ed Russell
President
mailing
PO Box 4982
Boulder
CO
80306
USA
303.444.1670
303.443.4856
ctm@ctmap.com
8:00-5:00 MT
This data set is the product of a collaborative process between numerous
agencies, organizations and interested individuals from the beautiful
Alpine Loop region.
GRASS version 5 on Red-Hat Linux version 8.0 exported to an ASCII Grid
Visual resources were calculated directly from NED. See
http://gisdata.usgs.net/NED/default.asp for accuracy information for NED.
Viewshed and skyline analyses were based on topographic features only.
Obstruction from vegetation (trees), buildings, etc. was not taken into
account.
Data are calculated from a single reliable source.
Only basic spot checking based on knowledge of terrain was performed.
Visual resources were calculated for the entire study area.
U.S. Geological Survey (USGS), EROS Data Center
1999
National Elevation Dataset
Sioux Falls, SD
USGS
<http://gisdata.usgs.net/ned/>
digital
1999
Unknown
Publication date
NED
Elevation data.
Computed viewshed, i.e., land area visible, from points sampled at 100m
spacing along a number of roads and trails in the area, including the
Alpine Loop; San Juan Skyway between Alpine Loop intersections
(Uncompahgre River to Silverton); Silverton to Gladstone (Cement Creek);
Corkscrew; Hurricane; California; Treasure Mountain (Placer and
Picayune); Stoney Pass; Cottonwood Creek Road; North Henson Creek Road;
Nellie Creek Road; Silver Creek Trail; Grizzly Gulch Trail; American
Basin Trail. BLM American Basin ACEC was also included.
NED
viewshed model
2005
Raster
Grid Cell
1256
1863
Universal Transverse Mercator
13
.9996
-105 00 00
00 00 00
500000
0
coordinate pair
30.0
30.0
METERS
North American Datum of 1983 (NAD83)
GRS 1980
6378137
298.257222101
Visual resource grid cell
Any of the data elements in the visual resource map
author
Visual grid cell value
The value represents the visibility of a structure combined with the
potential visibility of a structure above the skyline. The viewshed
and skyline results were added and categorized as low, medium or high
based on 33-percentiles. The lowest third of the visual resource
spectrum was assigned a 1; the middle third a 2 and the highest third
a 3. The BLM American Basin ACEC was also assigned a 3 value for its
high visual quality.
author
0
3
Computer Terrain Mapping, Inc.
Ed Russell
President
mailing
PO Box 4982
Boulder
CO
80306
USA
303.444.1670
303.443.4856
ctm@ctmap.com
Alpine Loop Spatial Analysis and Mapping Project
Computer Terrain Mapping, Inc. (CTM) provides this data set as is. CTM makes
no guarantee or warranty concerning the accuracy of information contained
in the data. CTM further makes no warranties, either expressed or implied
as to any other matter whatsoever, including, without limitation, the
condition of the product, or its fitness for any particular purpose. The
burden for determining fitness for use lies entirely with the user.
Although this data has been processed successfully on computers at CTM, no
warranty, expressed or implied, is made by the CTM regarding the use of
this data on any other system, nor does the fact of distribution
constitute or imply any such warranty.
Contact distributor to receive additional copies.
200504
Computer Terrain Mapping, Inc.
Ed Russell
President
mailing
PO Box 4982
Boulder
CO
80306
USA
303.444.1670
303.443.4856
ctm@ctmap.com
8:00-5:00 MT
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998