UIS mapping grades
Draft
submitted for comment, 18.8.2009, präzis
Introduction
At the 15th International Congress of Speleology in
Kerrville (USA), the working group "topography and mapping" of the UIS
Informatics Commission discussed the BCRA and ASF mapping grades, their
use, limitations, and possible upgrades for international use within the
UIS. The vast majority of the people present agreed that the use of a
grading system in speleological mapping was needed in order to inform
the map user of the expected accuracy of the map. After a lively
discussion, it was seen that the current ASF standards quite closely
match the expectations of the group and that they could be upgraded for
UIS use. The following tables present the grades, the accuracy of
details, additional information, and an explanation which helps to
understand the meaning of the tables.
Use
The agreed notation is "UIS 4-2-BC" for a survey
grade 4, map details 2, and additional qualification B and C.
The present grades are not valid for underwater measurements, since the
techniques, material, and difficulties may vary greatly. If an
indication is to be given, it should read "Equivalent to UIS 4-2-BC".
Ranges of UIS grades are not to be specified on the map. If the main
passage of the cave is mapped by theodolite, and the lateral passages to
grade 4, the grade to be indicated is the one that makes most sense to
indicate the real accuracy of the given passages; most of the time, it
will be the lower grade; if insignificant lateral portions (NOT the only
connection of two high-quality maps!) of the cave are mapped in a lower
grade, the higher grade may apply. Please keep in mind that those grades
are to indicate precision and accuracy; and although grade 5 should be
reached for a quality survey, it is not mandatory.
Especially for larger caves, details regarding on how the map was
compiled should figure in the written description of the cave. There,
also possible deviations from the general grade can be explained.
Techniques to minimize loop-closure errors, measurement techiques and
other additional detail can be given easily there.
Survey grades
Grade Description Precision Expected
length compass clino accuracy
-1 no map available - - - -
0 ungraded - - - -
1 Sketch from memory, not to scale - - - -
2 Map compiled from annotations, sketches and estimates made - - - -
in the cave. No instruments used.
3 Directions measured by compass, distances measured by chord, 0.5 m 5°
- 10 %
pace, or body dimensions. Significant slopes estimated.
4 Compass and tape survey, using deliberately chosen and fixed 0.1 m 2°
2° 5 %
stations. Slopes measured by clinometer or horizontal and vertical
components of line.
5 Compass and tape survey. Directions and slope by calibrated 0.05 m 1°
1° 2 %
instruments, distances by fibreglass or metallic tape, or tacheometry.
6 Survey or triangulation using calibrated, tripod-mounted instruments
0.02 cm 0.25° 0.25° 1 %
for directions and slope. Distances by calibrated tape, precise
tacheometry, or calibrated DistoX.
X Survey by theodolite or comparable means variable variable
Map detail grades
0 ungraded
1 Sketch from memory. Not to scale, but indicates approximate
proportions.
2 Details from annotations, sketches and estimates of directions and
dimensions made in the cave.
3 Details from drawings made in the cave. The drawing has not to be to
scale, passage dimensions can be estimated. Significant details have to
be drawn with sufficient accuracy.
4 Details from drawings made in the cave to scale, based on measurements
of significant details with respect to surveyed points, usually at least
grade 4. All details of general speleological interest should be shown
with sufficient accuracy so as not to be appreciably in error at the
mapping scale. Passage dimensions measured.
Qualifying suffixes
A nothing has been done to obtain additional
certainty of accuracy
B Survey loops are closed and adjusted.
C Survey is dependend on instruments and people which have been checked
and corrected for the effects of possible anomalies.
D Survey is checked and corrected by electromagnetic methods.
E Survey data has not been transcribed manually, but has been downloaded
electronically.
F Entrances have been precisely measured.
Additional notes
Grade -1:
Only for database purposes: It means that the cave map has not been
drawn yet.
Grade 0:
Only for database purposes. If a cave survey is ungraded, its quality
cannot be assessed. This is most usually true for historic or otherwise
old maps.
Grade 3:
A Silva clinometer or comparable, relatively simple means without
precise readings qualify for grade 3. Mapping from head to head of the
surveyors qualifies only for grade 3. Topofil measurements qualify
generally for grade 3 or 4.
Grade 4:
Topofil measurements may qualify for grade 4 if the survey shots are not
too long and care is given to correctly read all data. Laser rangefinder
can be used throughout grades 4 to 5. In order to attain grade 4, fixed
and re-findable survey stations must be made. They have not to be
necessarily on the walls; tripod-mounted points with a defined length
above the floor are also accepted.
Grade 5:
Calibrated DistoX, DUSI or comparable instruments attain grade 5, if the
length measurement has been calibrated, they attain grade 6. If they are
uncalibrated, they are to be graded with 1! Topofil used for vertical
pits may reach grade 5. In order to reach grade 5, the survey
coordinates have to be calculated (xyz coordinates, no polar coordinates
plotted with scale rule and protactor).
Grade X:
Theodolite models or other similar equipment may vary as well as the
measuring techniques. Therefore, all grade X surveys must include, in
the written description of the cave, descriptions of the instruments and
techniques used as well as an estimate of the probable accuracy of the
survey.
Map detail grade 4: The main difference between Detail grade 3 and 4 is
that in order to obtain grade 4, the drawing has to be made to scale
within the cave, either by calculating/reporting the lengths on paper,
or by drawing on computer outputs of previous surveys.
Suffix C:
Suffix C designates that compass, clinometer, and the people using this
equipment have been checked for anomalies. Magnetic anomalies at
compasses, inclination anomalies at clinometer, and eye anomalies with
persons are relatively common. In order to reach grade 5, all
instruments have to be calibrated, Grade 5 and suffix C are therefore
redundant. See http://www.sghbern.ch for a description of a possible
calibration setting.
Suffix D:
Used to inform that key locations of the passage have been radiolocated
by means of electromagnetic (or other) methods in order to ascertain
absolute positioning of the survey with respect to the land surface.
Suffix E:
Designates that the data have been downloaded eletronically from the
instruments (Distox etc.), thus eliminating possible transcription
errors.
Suffix F:
Suffix F will be used on either maps which represent different caves (to
indicate that the entrances have been measured precisely) or on cave
maps which are to contain absolute XYZ data on a grid. Without
additional information in the written description, it is assumed that
the measurement technique to locate the entrances was made at least
according to the grade that was used in the cave. Determination of
entrance coordinates from maps qualifies for grade 1 to 3 (for
high-quality maps); surface surveys for grade 3 through 6, and GPS
readings from 3 to X depending on the instruments and methods used,
availability of satellites etc. In order to reach suffix F, the position
of the entrance has to be determined either by surface survey of at
least grade 4, or by good GPS location or comparable means.
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