Thematic Accuracy Assessment Procedures. Version 2 - USGS

Table 1. Comparison of field observation activities in the National Park Service Vegetation Inventory.
ACTIVITY:
CLASSIFICATION MAP CALIBRATION MAP VERIFICATION MAP ACCURACY
PLOTS (RELEVES) VALIDATION ASSESSMENT
INTERNAL OR Internal Internal Internal External External
EXTERNAL TO
MAPPING PROCESS:
PHASE OF
PROJECT:
Production (Ecological
Classification)
SPECIFIC PURPOSE: Ecological Classification
(also map calibration)
Production (Mapping) Production (Mapping) Evaluation Evaluation
Produces first draft of
map
NEED: Required As needed
(recommended)
Checks and revises
first draft of map
As needed
(recommended)
SAMPLING DESIGN: Subjective Subjective Subjective (can be
stratified random)
AMOUNT OF
ATTRIBUTE DATA
PER OBSERVATION:
NUMBER OF
OBSERVATIONS:
Significant. Full floristic
enumeration with cover of
each species per stratum.
Substantial environmental
data.
5 plots per vegetation
type
Dominant / frequent /
diagnostic species, as
needed. Cover of these,
as needed. Little
environmental data.
Dominant / frequent /
diagnostic species,
as needed. Cover of
these, as needed.
Little environmental
data.
3-10 plots/ map class 3-10 plots/ map
class, as needed
Checks final draft
of map for
acceptance
Checks final
(accepted)
product
Required, if Required
acceptance of
product is
contingent on
performance
Stratified random Stratified random
Dominant /
frequent /
diagnostic species,
as needed. Cover
of these, as
needed.
1-3 per class, (30­
50 total)
Further guidance on these processes may be found in Appendix E and at: http://science.nature.nps.gov/im/inventory/veg/index.cfm.
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Relatively little.
Minimally, a
vegetation type
classified at the
site
5-30 points per
map class