HI AC RES QUICK REFERENCE GUIDE
Latitude, Longitude and Associated Metadata
The Property Profile Form (PPF) requests the property name, address, city, state and zip. From
these address fields, ACRES interfaces with Google Maps and extracts the latitude and longitude
(lat/long) for the property location. ACRES sets the remaining property geographic information to
default values. The data (known collectively as "metadata") are required by EPA Data Standards.
Should an ACRES user need to be update the metadata, the Edit Fields link on the PPF provides
the ability to change the information.
Before the metadata were populated by ACRES, the data were entered manually. There may still
be the need to do so, for example some properties do not have a specific street address (e.g. a
rural property located on a state highway) or an ACRES user may have an exact lat/long that is to
be used. This Quick Reference Guide covers how to find latitude and longitude, define the
metadata, fill out the associated fields in a Property Work Package, and convert latitude and
longitude to decimal degree format. This explains how the metadata were determined prior to
September 2011 (when the Google Maps interface was added to ACRES).
Definitions
Below are definitions of the six data elements for latitude and longitude data that are collected in a
Property Work Package. The definitions below are based on text from the EPA Data Standard.
•	Latitude: Is the measure of the angular distance on a meridian north or south of the
equator. Latitudinal lines run horizontal around the earth in parallel concentric lines from the
equator to each of the poles.
•	Longitude: Is the measure of the angular distance on a meridian east or west of the prime
meridian. Longitudinal lines extend from the north to South Pole around the earth, like
slices of an orange.
•	Horizontal Collection Method: Describes the method used to determine the latitude and
longitude coordinates for a point on the earth. This specifies what type of method or device
was used to identify the latitude and longitude, e.g., an address, an intersection, a Global
Positioning System (GPS) device, a census block centroid, etc. The key is that the
horizontal collection method determines how the coordinates were collected, not where.
•	Source Map Scale: The number that represents the proportional distance on the ground for
one unit of measure on the map or photo. For example, 1 inch corresponds to 50 feet on a
map. (Note: This is not filled out when using GPS).
•	Reference Point: The text that identifies the place for which the geographic coordinates
were established. This specifies the location at the place where the coordinates were taken,
e.g., entrance to a facility, center of a facility, etc. The key is that the reference point
determines where the coordinates were collected, not how.
•	Horizontal Reference Datum: The Horizontal Reference Datum is the coordinate reference
system to which the latitude/longitude data in 11a and 11b relate. Per EPA's
Latitude/Longitude Data Standard, there are three possible values associated with
horizontal reference datum.
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Refer to EPA's Data Standards for further explanations of the six required latitude and longitude
data elements which can be found at the following URL:
http://iaspub.epa.gov/sor internet/registry/datastds/findadatastandard/epaapproved/latitudelongitud
e/LatLongStandard 08112006. pdf.
How to Find Latitude and Longitude
The most common method to determine latitude and longitude of a property is using GPS to
electronically record the coordinates. It is also possible to use geographic information systems
(e.g., ArcView), electronic (Terra Server or Google Earth), or paper maps from trusted sources
(e.g., USGS) to identify latitude and longitude coordinates.
Using Online Sources to Determine Latitude and Longitude
If you do not have access to a GPS device, you may go online to www.terraserver.com and enter
the property address, nearest intersection, or zip code to determine the latitude and longitude. After
entering the address, intersection or zip code, press the Search button- the latitude and longitude
information will be displayed the Search box.
Using Google Earth, you can enter the property address, nearest intersection or zip code to
determine the latitude and longitude. The coordinates will be displayed at the bottom of the map
and may be in degrees, minutes, seconds format. If this is the case, you can change this by going
to the Tools menu on the toolbar and going down to Options. A new window will appear and on the
first tab you can change the latitude and longitudinal display to Decimal Degrees. After doing this,
the number format at the bottom of the screen will have changed.
Note: The EPA does not endorse TerraServer or Google Earth and only provides their
names as a possibility for use.
Using either Terra Server or Google Earth, you will be able to determine the properties latitude and
longitude, but the metadata fields must be completed as well. The Horizontal Collection Method
may be filled in as Interpolation - Satellite. Source Map Scale does not need to be filled out when
using one of these digital methods. The Property Reference Point will often be Address Matching
House Number or, if you looked up the property by identifying the nearest intersection, use Address
Matching Nearest Intersection. Horizontal Reference Datum may be filled in as North American
Datum of 1983.
How to Fill Out the Property Profile Form
Please enter the appropriate data into each field in the Property Work Package. The fields are
described below, with further guidance as to format and options.
When you enter a property into ACRES for the first time, ACRES will automatically calculate the
latitude and longitude based on the address you enter. If you edit or change the address, you can
update the latitude longitude calculation by clicking "Update Latitude/Longitude below based on
address" in the Property Background Information section of the Property Work Package.
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Field 11a- Latitude - Please enter the decimal format of the measure of the angular distance on a
meridian north or south of the equator. Latitudinal lines run horizontal around the earth in parallel
concentric lines from the equator to each of the poles. Methods for converting Degrees, Minutes,
Seconds format of latitude are provided at the end of this document.
Note: Latitude must be between 1 and 90 - and do not forget to indicate negative latitude, if
necessary.
Field 11b- Longitude - Please enter the decimal format of the measure of the angular distance on
a meridian east or west of the prime meridian. Longitudinal lines extend from the North to South
Pole around the earth, like slices of an orange. Methods for converting Hour, Minute, Second format
of longitude are provided at the end of this document.
Note: Longitude must be between 0 and 180 -do not forget to indicate a negative longitude,
if necessary.
Field 11c - Horizontal Collection Method - Please enter the text that describes the method used
to determine the latitude and longitude coordinates for a point on the earth. This specifies what
type of method or device was used to identify the latitude and longitude, e.g., an address, an
intersection, a GPS device, a census block centroid, etc. The key is that the horizontal collection
method determines how the coordinates were collected, not where. Below are the standard EPA
options for this field. Please indicate the most accurate option from this list.
Horizontal Collection Method possible responses (responses marked with an asterisk are the
most common):
* Address Matching -
House Number
The absolute location point is defined by an automated conversion
program based on a user-defined address. The primary characteristic
used to define the point is the address's house number.
Address Matching -
Block Face
The absolute location point is defined by an automated conversion
program based on a user-defined address. The primary characteristic
used to define the point is the city's block face.
Address Matching -
Street Centerline
The absolute location point is defined by an automated conversion
program based on a user-defined address. The primary characteristic
used to define the point is the address's street.
* Address Matching -
Nearest Intersection
The absolute location point is defined by an automated conversion
program based on a user-defined address. The primary characteristic
used to define the point is the nearest intersection to the identified
address.
Address Matching -
Primary Name
The absolute location point is defined by an automated conversion
program based on a user-defined address. The primary characteristic
used to define the point is the address's primary name.
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Address Matching -
Digitized
The absolute location point is defined by applying digitally geocoded
addresses to a digital map (MapQuest uses this technique). The process
involves locating two kinds of files that are needed to perform geocoding.
One file that contains the addresses which are to be address-matched
and the other which is the digital street map which gives the geographic
coordinates of the centerline of all streets, along with the range of street
addresses that are found on each street segment. The street files for
counties are available and downloaded from the ESRI website
(www.esri.com).
Address Matching -
Other
The absolute location point is defined by an automated conversion
program based on a user-defined address. The primary characteristic
used to define the point is other than one presented in this list.
Census Block -1990
- Centroid
Absolute location point is defined by relating the point of interest to a
known Census area where a latitude/longitude has been defined for its
centroid - based on the Census Block-1990 data set.
Census Block/Group
- 1990 - Centroid
The absolute location point is defined by relating the point of interest to a
known Census area where a latitude/longitude has been defined for its
centroid. This is based on the Census Block/Group-1990 data set.
Census Block/Tract
- 1990 - Centroid
The absolute location point is defined by relating the point of interest to a
known Census area where a latitude/longitude has been defined for its
centroid. This is based on the Census Block Tract-1990 data set.
Census - Other
The absolute location point is defined by relating the point of interest to a
known Census area where a latitude/longitude has been defined for its
centroid. This is based on a Census data set other than one presented in
this list.
GPS Carrier Phase
Static Position
The signal emitted from a GPS receiver is the location where the
receiver's antenna is presumed to be stationary on the Earth. The GPS
receiver will emit GPS measurements based on the L1 or L2 carrier
signal. These signals, a.k.a. GPS carrier frequencies, L1 (15735 MHz)
and L2 (1227.6 MHz), are in the L-band.
GPS Phase
Kinematic Relative
Position
Kinematic positioning refers to applications in which the position of a
non-stationary object (automobile, ship, bicycle) is determined. GPS
phase kinematic relative positioning are relative measurements "on the
fly" that may be made with using GPS receivers with kinematic packages.
Accuracies of these kinematic packages can be compared to the relative
positioning GPS. Real time kinematic GPS requires a radio link between
the field receiver and the base station.
GPS (Pseudo
Range) Differential
A technique to improve GPS accuracy that uses pseudo-range errors
measured at a known location to improve the measurements made by
other GPS receivers within the same general geographic area. Position
accuracies to about +/- 2 meters can be obtained by comparison of a field
GPS receiver with a fixed receiver at a known position. Basically, this
involves using two resource grade GPS receivers to determine the
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location of a point by taking several GPS reading in an area. *Note:
Pseudo-range refers to errors in a distance measurement based on the
correlation of a satellite transmitted code and the local receiver's
reference code that has not been corrected for errors in synchronization
between the transmitter's clock and the receiver's clock.
*GPS (Pseudo
Range) Precise
Position
The most accurate dynamic positioning possible with GPS, based on the
dual frequency P-code. This code (called the Precise Positioning System
or GPS) primarily available for the Department of Defense and national
security purposes. It is not for general public use.
GPS (Pseudo
Range) Standard
Position (SA off)
The US government discontinued the use of Selective Availability (SA)
and the GPS system became much more accurate. Currently, there are
no government specifications to determine what the average error will be
now. However, after performing a series of tests with SA "off" we have
seen the average error reduced to within 10 to 20 meters of a stationary
fixed position. With the addition of the Differential GPS receiver we have
seen this reduced further to an average error of less than 5 meters (about
16 feet.)
GPS (Pseudo
Range) Standard
Position (SA on)
A Standard Positioning Service (GPS) for general public use. Selective
Availability or SA is the intentional degradation of GPS signals which
directly affect the accuracy of all GPS receivers which use these satellite
signals.
GPS (Pseudo
Range) Standard -
Service Correction
Global Positioning System (GPS) applications that require consistent
accuracy of less than six inches in mobile equipment need a commercial
connection service. Normal civilian GPS positions are accurate to about
30 feet, and free differential correction services are accurate to
approximately three feet. To get consistent GPS positions within a few
inches, users must subscribe to a commercial GPS differential correction
service. Farmers and others who use accurate GPS correction signals
use the term RT. when referring to the most accurate GPS correction
signals. Real-time Kinematic (RT.) differential correction refers to Global
Positioning System (GPS) locations that are accurate to within a few
inches. Commercial companies that supply GPS differential correction
services often use the terms of centimeter and decimeter accuracies.
These precise GPS differential correction services are used for
agricultural equipment auto-steering systems and can be used for most
other GPS applications in agriculture. The highly accurate GPS differential
correction services use base stations with known locations to measure
GPS position errors and geosynchronous satellites to deliver the
corrections to receivers in mobile agriculture equipment.
Interpolation - Map
(1) Hard copy the absolute location point is defined by measuring relative
distances on a hard copy map through manual efforts. This requires basic
map knowledge about scales, conversions, projections, etc. (2) Digitized
the absolute location point is defined by measuring relative distances on a
map using a digitizer (tool used to translate paper based maps/photos
digitally for computer mapping purposes). This requires basic map
knowledge about scales, conversions, projections, etc.
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Interpolation - Photo
(1) Hard copy the absolute location point is defined by measuring relative
distances on hard copy aerial photographs through manual efforts. This
requires trained photo interpreter (a person who is trained in using low-
oblique aerial photos to view images in stereo. A photo interpreter also
can determine scales and order of aerial photos and also calculates
distances, building heights, land use, etc.) (2) Digitized The absolute
location point is defined by measuring relative distances on aerial
photographs using a digitizer (tool used to translate paper based
maps/photos digitally for computer mapping purposes). This method also
requires a trained photo interpreter.
Interpolation -
Satellite
(1) Hard copy The absolute location point is defined by measuring relative
distances on hard copy satellite images through manual efforts
(determining scales and order of satellite imagery to calculate distances,
building heights, land use, etc.). Requires a trained photo interpreter. (2)
Digitized The absolute location point is defined by measuring relative
distances on satellite images using a digitizer (tool used to translate paper
based maps/photos digitally for computer mapping purposes). This
requires a trained photo interpreter.
Interpolation - Other
The absolute location point is defined by measuring relative distances on
an object that is other than one presented in this list.
Loran C
The absolute location point is defined by using receivers and broadcasting
stations to calculate the distance from a known point through triangulation,
This requires knowledge of LORAN receivers, publications, and correction
methods. Background LORAN-C was originally developed to provide radio
navigation service for U.S. coastal waters and was later expanded to
include complete coverage of the continental U.S. as well as most of
Alaska. Twenty-four U.S. LORAN-C stations work in partnership with
Canadian and Russian stations to provide coverage in Canadian waters
and in the Bering Sea. LORAN-C provides better than 0.25 nautical mile
absolute accuracy for suitably equipped users within the published areas.
LORAN-C provides coverage for maritime navigation in U.S. coastal
areas. It provides navigation, location, and timing services for both civil
and military air, land and marine users. The LORAN-C system serves the
48 continental states, their coastal areas, and parts of Alaska.
Public Land Survey
Quarter Section
The absolute location point is defined by an automated conversion
program that relates U.S. Public Land Survey System (PASS.)
descriptions to a latitude/longitude. This conversion is based on
quartering.
Public Land Survey
Section
The Public Land Survey System (PLSS) is a method used in the United
States to locate and identify land, particularly for titles and deeds of farm
or rural land. The system is in use in all states except the first 13 states,
and Vermont, Texas, and Hawaii. The system has been in general use
since the Land Ordinance of 1785. Its basic units of area are the township
and section. It is sometimes referred to as the rectangular survey system.
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Classical Survey
The absolute location point is defined by using a traditional method of
measuring horizontal distances, elevations, directions, and angles. This
requires a trained, licensed surveyor.
Zip code - Centroid
The absolute location point is defined as the absolute location point that
is associated with the center of a zip code area where the point being
identified is located.
Unknown
Horizontal method used to define the latitude/longitude is unknown or
unspecified.
Global Positioning
Method -
unspecified
parameters
The absolute location point was determined using GPS, but the specific
parameters of the GPS use are unknown or were not indicated.
Digital Map Source
(TIGER)
The term TIGER® comes from the acronym Topological^ Integrated
Geographic Encoding and Referencing which is the name for the system
and digital database developed at the U.S. Census Bureau to support its
mapping needs for the Decennial Census and other Bureau programs.
The design of the TIGER® database adapts the theories of topology,
graph theory, and associated fields of mathematics to provide a
disciplined, mathematical description for the geographic structure of the
United States and its territories. The topological structure of the TIGER®
data base defines the location and relationship of streets, rivers, railroads,
and other features to each other and to the numerous geographic entities
for which the Census Bureau tabulates data from its censuses and
sample surveys. It is designed to assure no duplication of these features
or areas.
SPOT satellite
The SPOT imaging satellite provides digital elevation models (DEMs) and
vegetation imaging of any location on Earth. It allows realistic 3D
perspectives. DEMs are used as part of the simulation market which
includes civilian and military flight simulation, defense mission planning,
video-games, and other visualization-based applications. SPOT has the
capability to produce up to 80% of the required elevation models to
support image-based 3D mapping business worldwide. SPOT is the only
satellite system with the dedicated technology to create DEMs for
commercial distribution. SPOT was launched in 2002 and is managed by
Spot Image.
Multi-Spectral
Scanner
An instrument on some satellites (Landsat) used for imaging the earth.
An MSS image will have data recorded by the scanner from three or more
bands of the electromagnetic spectrum. Arclnfo (a GIS mapping program)
can read multispectral images in various formats.
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Thematic Mapper
Landsats 4 and 5, launched in 1982 and 1984, respectively, were
augmented with an advanced version of an Earth observation sensor
known as the Thematic Mapper (TM). The TM provides a significant
increase in data acquisition capability over the MSS in a number of ways.
The TM sensor has seven spectral bands Six acquire Earth reflectance
data, and one acquires Earth temperature data. The spatial resolution of
bands in the visible and reflective infrared regions is 30 m, some 2 1/2
times better than the Multispectral Scanner (MSS). The TM sensor also
has greater overall radiometric sensitivity than the MSS.
Public Land Survey
Eighth Section
The absolute location point is defined by an automated conversion
program that relates U.S. Public Land Survey System (PLSS) descriptions
to a latitude/longitude. This conversion is based on an eighth of a section.
Public Land Survey
Sixteenth Section
The absolute location point is defined by an automated conversion
program that relates U.S. Public Land Survey System (PLSS) descriptions
to a latitude/longitude. This conversion is based on a sixteenth of a
section.
Public Land Survey
Footing
The absolute location point is defined by an automated conversion
program that relates U.S. Public Land Survey System (PLSS) descriptions
to a latitude/longitude. This conversion is based on footing.
Zip code plus 4
The absolute location point is defined as the absolute location point that
is associated with the center of a zip code sector (plus 4 indicates the
section) where the point being identified is located.
Zip code plus 2
The absolute location point is defined as the absolute location point that
is associated with the center of a zip code section (plus 2 indicates the
section) where the point being identified is located.
Field 11 d - Source Map Scale Number - Please enter the number that represents the proportional
distance on the ground for one unit of measure on the map or photo. For example, 1 inch
corresponds to 50 feet on a map.
Note: This does not apply for methods using GPS.
Field 11e - Reference Point - Please enter the text that identifies the place for which the
geographic coordinates were established. This specifies the location at the place where the
coordinates were taken, e.g., entrance to a facility, center of a facility, etc. The key is that the
reference point determines where the coordinates were collected, not how. Below are the standard
EPA options for this field. Please indicate the most accurate option from this list. The starred
options below are the most likely reference points.
Reference Point possible responses (marked with an asterisk are the most common):
•	*Entrance Point of a Facility or Station
•	*Plant Entrance (General)
•	Center of a Facility or Station
•	Facility/Monitoring Site Boundary Point
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Point Where Substance Enters Facility/Monitoring Site (Can be Inside/Outside of a
Facility Site)
Point Where Substance is Processed, Treated, Settled, or Stored
Point Where Substance is Released
Point Where Substance is Monitored
Points Not Represented by 101-107
Field 11f — Horizontal Reference Datum - Please choose which Reference Datum was used. The
Horizontal Reference Datum is the coordinate reference system to which the latitude/longitude data
in 13a and 13b relate. Per EPA's Latitude/Longitude Data Standard, there are three possible values
associated with horizontal reference datum. If you used GPS to determine coordinates, by default
you will use World Geodetic System of 1984 (WGS84).
Horizontal Reference Datum possible responses:
•	North American Datum of 1927 (NAD27): This datum was based on the ground
survey in Europe and North America in the 19th century. NAD27 was the standard for
many years because the USGS published its topographic maps in this datum. If you are
reporting a location using a USGS 7.5-minute map, NAD27 is your default datum.
•	North American Datum of 1983 (NAD83): NAD83 updated NAD27 with current
measurements using radio astronomy and satellite observations. When the USGS
began publishing digital data, the NAD83 was used, which provided a more accurate
representation of the earth's shape and a more accurate depiction of the location of
objects on the earth.
•	World Geodetic System of 1984 (WGS84): This datum was developed from the
measurements calculated in the North American Datum of 1983. If you used a GPS to
calculate your latitude/longitude coordinates, WGS84 is the default datum.
How to Convert Degrees, Minutes, Seconds into Decimal Degrees
If a GPS unit is not available, the following online conversion tool can be used.
1.	Go to the following Web site: http://www.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html
2.	Enter the Degrees, Minutes, Seconds into the appropriate fields.
3.	Click on the "Submit Degrees, Minutes, Seconds" button.
4.	Copy the results into the appropriate fields on the Property Profile Form or directly into the
property Work Package in ACRES.
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QUICK REFERENCE
ACRES HELP DESK
acres_help@epa.gov or 703-284-8212
M-F, 9am-5pm EST
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