Data Analysis for Vegetation, Sensitive Area, and Soil Resource Mapping and 
Evaluation 
Vegetation Mapping : Vegetation maps for an area of approximately 
350,000 hectares were produced by manual interpretation of 1:30,000 scale U-2 
color infrared photographs. Soil mapping efforts in this phase of the mapping 
project were confined to documentation of certain soil characteristics during 
field verification and classification of mapped units. Soil characteristics 
measured were effective root depth, texture for the surface and subsurface 
horizons, and evaluation of the erosion hazard for the major vegetative units 
mapped. Areas not under the jurisdiction of BLM management were eliminated 
from the analysis. Mapping units, after field verification, were transferred 
(using a photo enlarger) to acetate overlays superimposed over planning unit 
maps at a scale of 2 M =lmi (3cm=lkm), or approximately 1:31,680. The classifi 
cation scheme used for the mapping effort was an adaption of Anderson (1973) 
with expansion of the scheme at the third and fourth levels based on BLM 
management needs. 
Sensitive Area Detection : "Sensitive area" in this project was the 
term used to refer to small yet significant sites within the rangeland 
environment, namely wet/dry meadows, reservoirs, springs, moist sites and small 
areas of valuable browse for wildlife. Search grids 5 cm square were utilized 
for the interpretation of the 1:30,000 scale photography for sensitive area 
detection. These areas were also transferred to acetate overlays on map sheets 
at 1:31,680 scale. 
Soil Resource Mapping and Evaluation : Multistage analysis was utilized 
to map soils on a reconnaissance level for a specific portion of the study area. 
ERTS-1 imagery, large scale photography (1:30,000 scale) and ground data were 
combined to evaluate these data products for mapping and evaluating land systems 
dominated by (a) soils derived from basic igneous parent materials, (b) 
Juniper-sagebrush and associated vegetative communities, and (c) landforms 
consisting of lava flows, domal structures, and lacustrine plains all of recent 
origin. 
Mapping soils based on vegetation-terrain types on a regional level 
requires a level of generalization inherent in the data received from the ERTS-1 
vehicle and displayed in photographic form. Mapping cells were located on the 
ERTS imagery within the study area based on dominance of vegetation-terrain 
types typical of the study area, and those areas designated for future intensive 
management by BLM resource specialists. The cells were approximately 25,000 
acres (approximately 10,000 hectares) in extent and corresponded to the area 
covered by one frame of U-2, CIR aerial photography at 1:30,000 scale. Maximum 
efficiency in ground analysis was gained by selecting mapping cells which 
represented a majority of the soil, the vegetation, and landform types in 
outlying areas which must be mapped based on extrapolation of information gained 
in the mapping cells. The number of soil profiles examined for a given land 
unit within a mapping cell was determined by the areal extent of that unit. If 
for example, a majority of the land units within a mapping cell were sagebrush 
communities on upland plateaus of shallow soil depth, then a majority of the 
profile examinations were located within this type. The location was ultimately