PE&RS September 2016 Public - page 662

662 September 2016 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
Table 3 Digital orthoimagery accuracy examples for current large and medium format metric cameras.
Common Orthoimagery Pixel Sizes Recommended Horizontal Accuracy Class
RMSEx and RMSEy(cm)
Orthoimage RMSEx and RMSEy
in terms of pixels Recommended use
1.25 cm
≤1.3 ≤1-pixel Highest accuracy work
2.5 2-pixels Standard Mapping and GIS work
≥3.8 ≥3-pixels Visualization and less accurate work
2.5 cm
≤2.5 ≤1-pixel Highest accuracy work
5.0 2-pixels Standard Mapping and GIS work
≥7.5 ≥3-pixels Visualization and less accurate work
5 cm
≤5.0 ≤1-pixel Highest accuracy work
10.0 2-pixels Standard Mapping and GIS work
≥15.0 ≥3-pixels Visualization and less accurate work
7.5 cm
≤7.5 ≤1-pixel Highest accuracy work
15.0 2-pixels Standard Mapping and GIS work
≥22.5 ≥3-pixels Visualization and less accurate work
15 cm
≤15.0 ≤1-pixel Highest accuracy work
30.0 2-pixels Standard Mapping and GIS work
≥45.0 ≥3-pixels Visualization and less accurate work
30 cm
≤30.0 ≤1-pixel Highest accuracy work
60.0 2-pixels Standard Mapping and GIS work
≥90.0 ≥3-pixels Visualization and less accurate work
60 cm
≤60.0 ≤1-pixel Highest accuracy work
120.0 2-pixels Standard Mapping and GIS work
≥180.0 ≥3-pixels Visualization and less accurate work
1 meter
≤100.0 ≤1-pixel Highest accuracy work
200.0 2-pixels Standard Mapping and GIS work
≥300.0 ≥3-pixels Visualization and less accurate work
2 meter
≤200.0 ≤1-pixel Highest accuracy work
400.0 2-pixels Standard Mapping and GIS work
≥600.0 ≥3-pixels Visualization and less accurate work
5 meter
≤500.0 ≤1-pixel Highest accuracy work
1,000.0 2-pixels Standard Mapping and GIS work
≥1,500.0 ≥3-pixels Visualization and less accurate work
Table 4, provided by the new ASPRS standard, helps the
users approximate an association between the new standard
accuracy class, approximate GSD of source imagery, and
equivalent map scale according to the legacy standards,
NMAS and ASPRS1990. Table 4 provides some guidelines
on approximating the map scale the 10-centimeter imagery
may support according to the old practices. In reference to the
values given in Table 4, the new standards states:
“The range of the approximate GSD of source imagery
is only provided as a general recommendation,
based on the current state of sensor technologies
and mapping practices. Different ranges may
be considered in the future depending on future
advances of such technologies and mapping
practices.”
“In the new standard, accuracy is expressed
independently from GSD, map scale or contour
interval. The map can be produced and labeled
according to the users need and not according to
the imagery resolution or map scale”