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1. Attribute item "GLG" (generalized geology) is abstracted from
fill colors, fill patterns and labels on UNESCO source maps denoting geologic
age of surficial outcrops. Rock units whose age is divided within a geologic
period on the map are attributed undivided. For instance, units labeled
"q", "qh", "qh`m", "qh`g", "qh`fg", "qh`f", "qh`e", "qh`t", "qh`r", "qp",
"qp`m", "qp`g", "qp`fg", "qp`f" and "qp`e" are attributed as "Q". A more
comprehensive discussion is offered below. Areas colored as surface water
bodies and ocean are attributed as "H2O". Areas outside of the political
entities comprising Region 4, Europe, and Asia Minor are attributed as
"oth". Where there are disagreements on the original map sheets between
the label and the fill color, or where printing errors occur, the preference
is given to the label in attributing the unit. In some cases, a judgement
is made according to the inferred geologic trend. Definitions for the values
are found below in the entity and attribute information section.
2. Standard verification of attribute reliability is performed with the Arc/Info labelerrors command to find polygons without assigned character value or with more than one value.
3. Plots are created of the coverage, colored and labeled by item "GLG" at the same scale, projection and map extent of each of the UNESCO source map sheets for the purposes of review and examination. Review was conducted by persons uninvolved in the compilation.
The geologic age generalized by USGS and the original UNESCO age classes are as follows:
Q = {q,qh,qh`m,qh`g,qh`fg,qh`f,qh`e,qh`t,qh`r,qp,qp`m,qp`g,qp`fg,qp`f,qp`e}
Qv = {V-q,B-qh,B-qp} T = {q+ng,m,ng,m4,m3,m3+2,pg,m2,m1}
Tv = {V-m,B-m}
CzMzv = {Vq-t,tq-t,B*q-t,aV*q-t,V`t*q-t,L`t*q-t}
CzMzi = {G-ne,M-ne,O-ne,U-ne,a-ne}
TK = {m+c}
Mz = {ms}
MzPz = {ms+pl,t+p}
K = {c,c2,c1}
KJ = {c+j}
J = {j,j3,j2,j1}
JTr = {j+t}
Tr = {t,t3,t2,t1}
Pz = {pl,pl2,pl1,h+d}
Pzv = {V*p-pr,L*p-pr,B*p-pr,aV*p-pr}
Pzi = {Mpl,Opl,Upl,aMpl}
P = {p,p2,p1}
C = {h,h2,h2`h,h1,h1`h}
D = {d,d3,d2,d1}
S = {s}
SO = {s+o}
O = {o}
Cm = {cb}
Pz = {pl}
Pzm = (Paleozoic age color or label with metamorphic fill patterns
present)
Pzl = {pl1, s+cb}
Pzu = {pl2}
PzpCm = {eo,s+eo,cm+eo,pl+eo,pl1+eo}
PzpCmm = {eo,s+eo,cm+eo,pl+eo,pl1+eo}(metmamorphic fill patterns present)
pCm = {eo,pl+pr,pr,prA,prB,prC,prD,G-pr2,G-prA,G-prB,M-pr2,M-prA,G-pr1,
G-prC,G-prD,M-prC,I-pr,O-pr,U-pr,aM-pr}
Metamorphic rocks (Mzm,Pzm) were defined by metamorphic fill patterns
on source map sheets.
The following describe the tolerances:
1. Original geologic maps are presumed to be of 500 meter maximum accuracy (0.1mm at 1/5,000,000 scale)
2. Scanned images are of 200 dot/inch resolution (0.13 mm on paper map)
3. Scanned images were registered and rectified with an average RMS error of ~600 meters. (0.06 mm on paper map)
4. Fuzzy tolerance was set at 250 meters (0.31 pixel) and weed tolerance was set at 250 meters (0.31 pixel)
5. 100 points were sampled on the master coverage
for fit with ESRI Arcworld country boundaries and an RMS error was calculated
of 1,437 meters, the maximum error was 5,045 meters.