Beutner, Sabine
3.3 Generation of Orthoimages
All aerial images B/W and color are scanned at a resolution of 21 um pixelsize at the Agfa Horizon image scanner. In |
case of the Palpa block this corresponds to a footprint of 15 cm. This is about the size of the most narrow geoglyph lines,
For orthoimage generation and mosaicking we used the Leica/Helava DPW 770. The largest mosaick consists of 34
images and requires 1,4 GB storage space. For texture mapping different resolution levels are available (25 cm up to 2m
footprint).
3.4 Extraction of Geoglyphs in Vector Form
The 3-D mapping of geoglyphs is a very sensitive business and was done manually on the Analytical Plotter S9. Since
archeological knowledge is indispensable for correct interpretation the stereomeasurements were done by K. Lambers,
an archeologist on the project. For later analysis on a GIS platform we had to develop a system of attributes for the vari- A
ous types of geoglyphs and other items of interest, like ancient settlements, fortification walls, terraces and platforms and e
the like.
The feature codes were stored as 3-D objects in the special xmp format of the mapping software xmap which was used
on the Analytical Plotter. This format was converted into dxf format with feature codes. Maps for overview and with
detailed content have been generated by using ArcView Release 3.1. The attributes also contain information on stratigra-
phy and type of generation (negative/positive areas, heaped/cleared/furrowed lines). The classification scheme of the
geoglyphs is indicated in Figure 5. Currently the vector map including attributation is verified by archeologists in the
field.
Archeological objects
Geoglyphs Constructions Groups of arch. objects
A = Buildings Settlement L-
Line rea house Figure
T Way platform Cemetery
—>Figural ——-Figural street terrace
anthropomorphic anthropomorphic path wall Looted Area 4 VIS
zoomorphic zoomorphic Other stonewall Other
other Geometric other Geometric Lp. Depression euim
i ; ole canal other
[p straight line rectangi :
zigzag line > trapezoid pit
spiral triangle other
other combined
other
Figure 5. Classification scheme of the geoglyphs. The lowest level (stratigraphy and generation mode) are not shown.
Within the project area of Palpa alone we generated more than 9500 vector segments. Figure 6 shows three particular
objects (from left: double spiral, “astronaut”, whale; compare also Figure 1). Figure 7 shows a small section of the whole
area.
Figure 6. Various Palpa geoglyphs. From left: double spiral, “astronaut”, whale
In general, the pampa of Nasca, San Ignacio and Palpa have a very rich in iconography. Besides many anthropomorphic
figures we find zoomorphic objects such as whale, monkey, dog, anteater, condor, hummingbird, parrot, chaucato, fla
mingo, frigate bird, pelican, snake, spider, lizzard, dragonfly and plantlike species such as tree, flower, spices, etc. igure
58 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B5. Amsterdam 2000.
