Project to evaluate the visibility of a proposed surface mine
near the new river gorge national river (a unit of the national
park service)
WVDEP uses X-band RADAR is for visualization because it models
tree canopy.
WVDEP has 10 counties of IFSAR data for southern West Virginia,
and has used it several times to access visibility of mining
operations.
Data was acquired by intermap, who files a modified lear jet at
high altitudes to capture a 10km wide swath of data in a single
pass.The data products is a 5-meter grid exhibiting 1-2m RMSE
vertical accuracy, varying by slope
*Proposed mine permit is outlined in yellow.
The inset shows the rough texture of the X-Band RADAR, modeling
the tree canopy. Inside the permit boundary, the SAMB elevation
dataset was used to model the surface of the disturbed areaAfter
trees were removed. The area of mineral removal was modeled as a
flat plane at the approximate base of the coal seam. This maximized
the potential visibility of the mineral removal area
ESRI Viewshed command calculates how many points in the input
file are visible at each grid cell in the study area
If the input file is a regular grid of points overlaid on the
proposed mine site, the output willrepresent how much of the mine
will be visible at each point in the study area
If each input point is assumed to represent the center of a cell
of a constant size, the total numberof points visible can be
multiplied by the sell area to obtain a rough estimate of the
number ofacres that are visible at a particular point.
*Initial difference grid. Red indicates elevation loss, blue
indicates elevation gain*Results following the application of the
forest mask and an error threshold, Which isolated cut/fill areas,
but included a significant number of error artifacts*Potential
fills, with cut areas removed*Vectorized fill candidates.
Numerous metrics were associated with each vector polygon to
separate actual fills from error artifacts,Including proximity a
cut area, variance in depth, minimum and maximum depth, and
percentage of a fill that drained to a single point.
The metrics assisted in eliminating obvious errors and
identifying obvious fills, but no foolproof rule set was found that
separated the two automatically. Processing was conducted to
eliminate errors of omission as much as possible, with the last
error artifacts removed by manual inspection.*
Final fill inventory, comprising over 1,300 valley fills, refuse
fills, and slurry impoundments. The study identified over 500 fills
that were not present in the DEPs fill inventory compiled from
available permit maps.
Represents the first application I am aware of that applies
change detection principles to multi-date elevation data.
**Cross section of highwalls created from contour auger
mining.*Hillshade representation of highwalls created from mining
two approximately horizontal coal seams.*Slope map of the same
area.*Slopes over 45 degrees, which effectively isolate highwall
features.*Result after running ESRIs THIN command and converting to
vector lines. This command greatly simplified the process of
creating a vector-based highwall inventory.
A series of metrics was used to significantly reduce the initial
candidate set and isolate actual highwalls. These included, average
change in elevation, and average distance to an area of less than
10 percent slope.
*After removing error artifacts, estimates of height and slope
were calculated for each highwall segment, a program created
perpendicular line segments that were clipped to areas greater than
45-degrees slope.The height of the highwall, and the slope, was
calculated by sampling elevation at the endpoints of the clipped
line, and these values were assigned to the associated segment.
*Final highwall database, showing the estimated height of
individual highwall segments.*Comparison with the existing highwall
inventory. Lower left shows new highwall segments not currently in
the highwall inventoryUpper right shows the refined detail that the
analysis provided over the generalized representations in the
current inventory.The analysis identified over 150 miles of
highwalls not currently in the inventory, effectively doubling the
current amount.
*
