United States
Environmental Protection
Agency
Environmental
Research Laboratory
Corvallis OR 97333
Research and Development
EPA/600/S3-89/001 Aug. 1989
&EPA Project Summary
Geographic Information System
Documentation of Watershed
Data for Direct/Delayed
Response Project —
Northeast Database
Dorothy Mortenson
The Direct/Delayed Response Pro-
ject (DORP) was designed by the U.S.
Environmental Protection Agency
(EPA) within the National Acid Precip-
itation Assessment Program (NAPAP)
to predict the long-term response of
watersheds and surface waters to
acidic deposition. The purpose of the
ODRP is to investigate and distin-
guish the time scales over which
surface water systems might change
chemically under varying levels of
acidic deposition. The DORP is
examining a sub-set of watersheds
sampled in the EPA - National Sur-
face Water Survey (NSWS). In the
Northeast Region of the United
States, 145 watersheds are under
study. The DDRP required detailed
watershed information on those char-
acteristics thought important relative
to the effects of acid deposition. This
information was then mapped, then
entered into a Geographic Informa-
tion System (GIS). The purpose of
this document is to discuss what
protocols, guidelines, and standards
were used to complete GIS entry of
the mapping data, and what quality
control procedures were used to
ensure accuracy and consistency.
This Project Summary was devel-
oped by EPA's Environmental Re-
search Laboratory, Corvallis, OR, to
announce key findings of the research
project that is fully documented In a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
The Direct/Delayed Response Project
(DDRP) was designed by the U.S. Envi-
ronmental Protection Agency (EPA)
within the National Acid Precipitation
Assessment Program (NAPAP) to predict
the long-term response of watersheds
and surface waters to acidic deposition.
The purpose of the DDRP is to investi-
gate and distinguish the time scales over
which surface water systems might
change chemically under varying levels
of acidic deposition. The DDRP is exam-
ining a sub-set of watersheds sampled in
the EPA - National Surface Water Survey
(NSWS). In the northeast United States,
145 watersheds are under study.
The DDRP required detailed watershed
information on those characteristics
thought important relative to the effects of
acid deposition. Such characteristics
include soils, vegetation, depth to bed-
rock, land use, geology, and streams.
This information was mapped by the
USDA - Soil Conservation Service and
EPA - Environmental Monitoring Systems
Laboratory in Las Vegas (EMLS-LV) in
cooperation with the EPA. These maps
were then entered into a Geographic
Information System (GIS). The purpose of
this document is to discuss what proto-
cols, guidelines, and standards were
used to complete GIS entry of the
mapping data, and what quality control
-------
(QC) procedures were used to ensure
accuracy and consistency.
General Procedures
Although the mapped information came
from several different sources, the same
general QC measures were taken to
ensure accuracy and consistency. First,
the registration of the manuscript maps
was checked. Any necessary corrections
were made before proceeding. Second, a
standard allowance for transformation
error was set to control the accuracy of
digital registration. Third, editing software
was used to detect and correct any errors
within a coverage. Next, preliminary plots
were made and overlaid with the original
maps. Any line discrepancies were
corrected before continuing. Attributes
were written on each plot and then added
to the digitized map. The attributes were
checked with the data file for com-
pleteness. The coverage was then plotted
for the final quality check. This plot was
overlaid with the original map and
checked for line and attribute dis-
crepancies. If an error was found, it was
corrected and any necessary QC
procedures repeated. If no errors were
found, the plot was checked again
individually by another technician. If any
discrepancies were found by the second
technician, they were corrected and any
necessary QC procedures repeated until
both technicians agreed the final plot to
be accurate.
After the data were entered, further QC
measures were taken. First the attributes
were listed, sorted, and checked for con
sistency and accuracy throughout thi
dataset. Next, total area for eacl
coverage within a particular watershei
was calculated and compared. Lastly, thi
data were compiled into reports for thi
project analysis. These reports matchei
the attribute code to the description c
that code. Any possible ambiguou
codes were detected and suitably
modified during this process.
Conclusion
These QC procedures were followec
throughout the entire dataset. W<
conclude that there is only a minima
amount of error introduced durinc
digitization of the mapped data.
Dorothy Morten son is with NSI, Corvallis, OR 97333.
M. ft. Church is the EPA Project Officer (see below).
The complete report, entitled "Geographical Information System Documentation of
Watershed Data for Direct/Delayed Response Project—Northeast Database,"
(Order No. PB 89-222 483*'AS; Cost: $13.95, subject to change) will be available
only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at: '&
Environmental Research Laboratory *
U.S. Environmental Protection Agency
Corvallis, OR 97333
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
: "." I >'., ,i i.'i- tii-
•-•- I
• •, -- n ? r;
Official Business
Penalty for Private Use $300
EPA/600/S3-89/001
FIRST CLAS
-------
United States
Environmental Protection
Agency
Environmental
Research Laboratory
Corvallis OR 97333
Research and Development
EPA/600/S3-89/001 Aug. 1989
&EPA Project Summary
Geographic Information System
Documentation of Watershed
Data for Direct/Delayed
Response Project —
Northeast Database
Dorothy Mortenson
The Direct/Delayed Response Pro-
ject (DORP) was designed by the U.S.
Environmental Protection Agency
(EPA) within the National Acid Precip-
itation Assessment Program (NAPAP)
to predict the long-term response of
watersheds and surface waters to
acidic deposition. The purpose of the
DDRP is to investigate and distin-
guish the time scales over which
surface water systems might change
chemically under varying levels of
acidic deposition. The DDRP is
examining a sub-set of watersheds
sampled in the EPA - National Sur-
face Water Survey (NSWS). In the
Northeast Region of the United
States, 145 watersheds are under
study. The DDRP required detailed
watershed information on those char-
acteristics thought important relative
to the effects of acid deposition. This
information was then mapped, then
entered into a Geographic Informa-
tion System (GIS). The purpose of
this document is to discuss what
protocols, guidelines, and standards
were used to complete GIS entry of
the mapping data, and what quality
control procedures were used to
ensure accuracy and consistency.
This Project Summary was devel-
oped by EPA's Environmental Re-
search Laboratory, Corvallis, OR, to
announce key findings of the research
project that is fully documented In a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
The Direct/Delayed Response Project
(DDRP) was designed by the U.S. Envi-
ronmental Protection Agency (EPA)
within the National Acid Precipitation
Assessment Program (NAPAP) to predict
the long-term response of watersheds
and surface waters to acidic deposition.
The purpose of the DDRP is to investi-
gate and distinguish the time scales over
which surface water systems might
change chemically under varying levels
of acidic deposition. The DDRP is exam-
ining a sub-set of watersheds sampled in
the EPA - National Surface Water Survey
(NSWS). In the northeast United States,
145 watersheds are under study.
The DDRP required detailed watershed
information on those characteristics
thought important relative to the effects of
acid deposition. Such characteristics
include soils, vegetation, depth to bed-
rock, land use, geology, and streams.
This information was mapped by the
USDA - Soil Conservation Service and
EPA - Environmental Monitoring Systems
Laboratory in Las Vegas (EMLS-LV) in
cooperation with the EPA. These maps
were then entered into a Geographic
Information System (GIS). The purpose of
this document is to discuss what proto-
cols, guidelines, and standards were
used to complete GIS entry of the
mapping data, and what quality control
-------
(QC) procedures were used to ensure
accuracy and consistency.
General Procedures
Although the mapped information came
from several different sources, the same
general QC measures were taken to
ensure accuracy and consistency. First,
the registration of the manuscript maps
was checked. Any necessary corrections
were made before proceeding. Second, a
standard allowance for transformation
error was set to control the accuracy of
digital registration. Third, editing software
was used to detect and correct any errors
within a coverage. Next, preliminary plots
were made and overlaid with the original
maps. Any line discrepancies were
corrected before continuing. Attributes
were written on each plot and then added
to the digitized map. The attributes were
checked with the data file for com-
pleteness. The coverage was then plotted
for the final quality check. This plot was
overlaid with the original map and
checked for line and attribute dis-
crepancies. If an error was found, it was
corrected and any necessary QC
procedures repeated. If no errors were
found, the plot was checked again
individually by another technician. If any
discrepancies were found by the second
technician, they were corrected and any
necessary QC procedures repeated until
both technicians agreed the final plot to
be accurate.
After the data were entered, further QC
measures were taken. First the attributes
were listed, sorted, and checked for con-
sistency and accuracy throughout the
dataset. Next, total area for each
coverage within a particular watershed
was calculated and compared. Lastly, the
data were compiled into reports for the
project analysis. These reports matched
the attribute code to the description of
that code. Any possible ambiguous
codes were detected and suitably
modified during this process.
Conclusion
These QC procedures were followed
throughout the entire dataset. We
conclude that there is only a minimal
amount of error introduced during
digitization of the mapped data.
Dorothy Mortenson is with NSI, Corvallis, OR 97333.
M. R. Church is the EPA Project Officer (see below).
The complete report, entitled "Geographical Information System Documentation of
Watershed Data for Direct/Delayed Response Project—Northeast Database,"
(Order No. PB 89-222 4831 AS; Cost: $13.95, subject to change) will be available
only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650 %
The EPA Project Officer can be contacted at:
Environmental Research Laboratory
U.S. Environmental Protection Agency
Corvallis, OR 97333
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S3-89/001
FIRST
------- |