United States 

 Department of 

 Agriculture

 

 National

 Agricultural 

 Statistics 

 Service

 Research and 

 Development Division

 Washington DC 20250

 RDD Research Report 

 Number RDD-06-02

 

September 2006

Using Handheld Global 

Positioning System 

Receivers for the June 

Area Survey 

Michael W. Gerling 

This report was prepared for limited distribution to the research community outside the United States 

Department of Agriculture. The views expressed herein are not necessarily those of the National 

Agricultural Statistics Service or of the United States Department of Agriculture. 

i 

EXECUTIVE SUMMARY 

In 2005, the Washington Field Office (WA FO) and the Research and Development Division 

(RDD) demonstrated that handheld Global Positioning System (GPS) receivers could be utilized 

successfully for the Agricultural Resource Management Survey Phase II (ARMS II). 

Afterwards, the WA FO and RDD explored the use of GPS receivers for the June Area Survey. 

Currently, June Area Survey field enumerators use county-highway maps and aerial photos to 

reach sampled segments outlined on the aerial photos for enumeration. Sometimes there are no 

road signs and the geography of the land is so similar that determining where a particular 

segment is located can be time consuming and could lead to collecting information for the wrong 

land area, which would adversely affect data quality. Hence, this research project’s primary goal 

was to see if handheld GPS receivers could assist enumerators in locating sampled segments. 

Thirty-nine Washington field enumerators were provided with handheld GPS receivers 

previously used for the ARMS II. Additionally, the centroids (center points of the segments) 

were provided on the back of the aerial photos for each of Washington’s 267 segments. Field 

enumerators could then compare their GPS receiver’s reading with the segment’s centroid to 

verify if they were in the general vicinity of the segment or several miles away. The GPS 

receivers could not display where the boundary lines of the segments were, but rather would only 

assist the enumerators in reaching the general vicinity of each segment. 

For each segment, the enumerators were instructed to complete a feedback form pertaining to 

whether the GPS receivers were needed and if so, helpful or not. Of the 267 segments 

enumerated, 198 feedback forms were returned. The GPS receivers were used to locate/verify 

the locations of 25 segments. Eight times the enumerator found the GPS receiver useful in 

locating the segment. The remaining 17 times the receivers were used for verification purposes. 

This limited use of GPS receivers was due to four reasons. First, the field enumerators had 

enumerated 241 of these segments last year. Each year only 20 percent of the segments are 

replaced with new segments and since the field enumerators are typically assigned segments by 

their geographical location, they will likely return to many of the same segments for several 

years. Second, the enumerators typically work around the area they reside and thus acquire 

knowledge of the surrounding agricultural operations and the local area itself. Third, the field 

enumerators were instructed to use their GPS receivers only if they were unable to locate the 

sampled segments through conventional means. Finally, the enumerators were simply able to 

use their county-highway maps and aerial photos to locate the segments. Although these 

reasons for not using the GPS receivers weren’t unexpected, the project did show that the GPS 

receivers helped the enumerators locate some segments which likely saved time and may have 

lessened the chance of collecting data for wrong areas. 

The next page shows the Cost/Benefit of using GPS receivers for the June Area Survey in 

Washington. 
ii 

Cost-Benefit Summary: 

Costs Benefits 

●

●

●

$50 Batteries and miscellaneous 

 supplies. 

1 hr. Statistician time in preparing 

 and training enumerators. 

$160 Total enumerator training 

 expenses. 

●

●

●

Helped enumerators locate 8 segments 

(3 percent). 

Used for verifying the location of 17 

segments (6 percent). 

Re-use the GPS receivers over multiple 

years and for other projects such as for 

ARMS II. 
iii 

RECOMMENDATION 

1. Recommend field offices already having Global Positioning System (GPS) receivers use 

them for the June Area Survey since, with minimal expense, there is potential to improve 

data quality and save enumeration time. However, do not recommend purchasing GPS 

receivers for additional field offices since the savings were not measurable. 

1 

Using Handheld Global Positioning System Receivers for the June 

Area Survey 

Michael W. Gerling1/

Abstract 

The National Agricultural Statistics Service (NASS) surveys United States’ and

Puerto Rico’s agriculture for the purpose of making estimates on crops, livestock, 

production practices, farm economics, etc. 

One of these surveys is the annual June Area Survey. The survey requires field 

enumerators to physically go to sampled land areas (segments) designated on 

aerial photos and collect information on agricultural activity within the land area. 

Sometimes these land areas are difficult to find due to similarity in geography and 

missing road signs. 

In 2005, NASS researched whether handheld Global Positioning System (GPS)

receivers would be helpful in locating the sampled segments. All aerial photos 

contained the latitude and longitude coordinates of the centroid of the segments

for the enumerators to compare with their readings on the GPS receivers. Field 

enumerators could then tell if they were in the general location of a segment or 

miles away. 

KEY WORDS: Agricultural Survey, Data Collection, GPS, Segment 

1. INTRODUCTION 

The National Agricultural 

Statistics Service’s (NASS) primary 

purpose is to provide timely, 

accurate and useful statistics on

United States and Puerto Rico

agriculture. NASS conducts 

hundreds of surveys for the purpose 

of making estimates on crops, 

livestock, production practices, farm 

economics, etc. 

The June Area Survey (JAS) 

is conducted annually and collects 

___________________ 

1/ Michael W. Gerling is a Mathematical Statistician with the National Agricultural Statistics 

 Service - Research & Development Division, located at Room 305, 3251 Old Lee Highway, 

 Fairfax, VA 22030. A special thanks to the Washington Field Office, Washington’s Field 

 Enumerators, Dave Losh and Dan Beckler for their dedication and commitment in making 

 this research project a success.
2 

agricultural information for sampled land 

areas, referred to as segments. Field 

enumerators were provided with handheld 

Global Positioning System (GPS) receivers 

to see if these devices would help in locating 

segments for the 2005 June Area Survey. 

2. JUNE AREA SURVEY 

The June Area Survey provides 

information about U.S. crops, livestock, 

grain storage capacity, and type and size of 

farms. The June Area Survey’s sample is 

comprised of designated land areas 

(segments) which field enumerators visit to 

collect data on all agricultural activity 

occurring within the segments. Each 

segment is outlined on an aerial photo which 

is provided to the appropriate field 

enumerator. A typical segment is about one 

square mile, which is equivalent to 640 

acres. 

3. ARMS II TO JAS 

In 2005, NASS’ Washington Field 

Office (WA FO) and NASS’ Research and 

Development Division (RDD) successfully 

showed that handheld Global Positioning 

System receivers could be used for the 

Agricultural Resource Management Survey 

Phase II (ARMS II). See Gerling, 2005. 

The WA FO and RDD next investigated 

using GPS receivers for the June Area 

Survey. This research project’s goal was to 

see if GPS receivers could assist field 

enumerators in locating the June Area 

Survey segments. 

4. WHAT IS A GPS HANDHELD 

RECEIVER? 

The Global Positioning System is 

comprised of at least twenty-four satellites 

orbiting the earth. These satellites transmit 

signals to GPS receivers on the ground. The 

majority of GPS receivers are about the size 

of a standard television remote control. 

A GPS receiver only receives signals 

from the satellites. It does not transmit. To 

function properly, a GPS receiver requires 

an unobstructed view of the sky. 

First, the GPS receiver acquires 

signals from these various satellites. Next, 

the GPS receiver determines the location of 

the satellites from the information included 

in the satellites’ transmissions. The receiver 

then determines the distance it is from each 

satellite. Finally, the receiver is able to 

determine where it is actually located on the 

Earth within a certain degree of accuracy. 

The receiver will display its location 

in latitude and longitude coordinates. 

Latitude measures the distance north or 

south from the Equator while longitude 

measures the distance east and west from the 

Prime Meridian. 

A common use of GPS receivers is 

for hiking. Hikers utilize these receivers to 

trace their trail or to mark a unique location 

that they would like to return to at a later 

date. 

The particular GPS receiver used 

was the Garmin GPS-72. See Figure 1. 

These GPS receivers were the same 

receivers purchased and used for the ARMS 

II research project conducted in the fall of 

2004. At that time Garmin was selected 

because the company was a respected 

manufacturer of GPS receivers for 15 years. 

The GPS-72 model was also among the 

lowest-price GPS receivers ($150) offering 

Wide Area Augmentation System (WAAS). 

WAAS provides the potential to obtain a 

level of accuracy of ten feet. Typically, the 

GPS-72 receiver will provide a level of 

accuracy between 10 and 50 feet. 
3 

Figure 1: Garmin GPS-72 

5. THE RESEARCH PROJECT 

Thirty-four of Washington’s 39 field 

enumerators working the June Area Survey 

were supplied with a Garmin GPS-72 

receiver. Not all field enumerators were 

supplied with a receiver since one field

supervisor had miscommunicated the 

number of enumerators working the survey.

These field enumerators, however, were able 

to share the allocated GPS-72 receivers.

Washington’s 2005 JAS sample size 

was 267 segments. The centroid (center 

point) was provided on the back of each 

segment’s aerial photo. 

The field enumerators were

instructed to use their GPS receivers if they

were unable to locate the sampled segments 

using their county-highway maps and aerial 

photos. 

The GPS receiver would display the 

enumerator’s location in latitude and 

longitude coordinates. The field 

enumerators would then compare their GPS 

coordinates with those on the aerial photos. 

Finally, using their provided handouts on 

distances, the enumerators would determine 

if they were in the general vicinity or several 

miles from the segment. The handout 

contained a conversion chart showing what

the difference in degrees, minutes, and 

seconds between two points equates to in 

feet and miles. The GPS receivers could not 

display where the boundary lines of the

segments were, but rather would only assist 

the enumerators in reaching the general 

vicinity of each segment. 

They were also instructed to 

complete an enumerator feedback form for 

each sample asking if the GPS receiver was

needed and if so, helpful or not. See

Appendix A for a copy of the EnumeratorFeedback Form. 

 

6. ENUMERATOR TRAINING 

Each year a June Area Survey 

Workshop is conducted to review details of 

the survey and data collection procedures. 

Educating all 39 field enumerators on how 

to use the GPS receiver was incorporated

into the workshop. 

The GPS receiver training took 

approximately 20 minutes. Fourteen of the 

39 field enumerators were new to using a 

GPS receiver. The other 25 field 

enumerators had used GPS receivers for 

ARMS II. An instructional handout was 

provided, explaining the use of the GPS 
4 

receivers and how to convert the difference 

between the GPS receiver’s coordinates with 

that of the aerial photo’s coordinates in 

order to determine how far he/she is from 

the center point of the segment. See 

Appendix B for a copy of the instructional 

handout. 

7. FINDINGS 

Despite being a requirement, only 

198 enumerator feedback forms out of a 

possible 267 forms, were returned. The 

following numbers are based on these 198 

feedback forms, unless otherwise noted. 

Eleven (28%) of the 39 enumerators 

used the GPS receivers to find or verify the 

location of 25 segments. This equates to 

nine percent of the 267 segments. This 

limited GPS receiver usage was primarily 

due to four reasons. First, the field 

enumerators were instructed to use their 

GPS receivers only if they were unable to 

locate the sampled segments through 

conventional means. Second, the field 

enumerators had enumerated 241 of the 267 

segments last year. Each year 

approximately 20 percent of the segments 

are replaced with new segments and since 

the field enumerators are typically assigned 

segments by their geographical location, 

enumerators likely return to many of the 

same segments each year. Third, the 

enumerators typically work around the area 

they reside and thus acquire knowledge of 

the surrounding agricultural operations and 

the local area itself. Finally, the 

enumerators were simply able to use their 

county-highway maps and aerial photos to 

locate the segments.

 For eight of these 25 segments, the 

enumerators stated that the GPS receivers 

helped them locate the segment. For the 

other 17, the GPS receivers were used to 

verify that the enumerator was in the general 

vicinity of the segment. However, one 

enumerator accounted for eight of these 

verifications. 

 There were 41 new segments rotated 

in Washington’s JAS. As stated earlier, 

approximately 20 percent of the segments 

are replaced by new segments each year. 

The receivers were used in finding seven 

(17%) of these 41 new segments. Table 1 

displays some of these findings. 

Table 1: GPS Receiver Usage 

Segments Description Count Percent 

Number of 

Enumerators3/

GPS receivers used to locate segment. 81/ 3 6 

GPS receivers used to verify segment location. 17 6 6 

GPS receivers not used to locate/verify segment. 2422/ 91 284/

Total 267 100 395/

 1/ Seven of the eight segments were new segments. 

 2/ Assumes those segments without returned feedback forms didn’t require a GPS receiver. 

 3/ Enumerators may be counted more than once. 

 4/ Number of enumerators not using GPS receivers at all. 

 5/ Total number of enumerators (not double counted). 
5 

 All of the enumerators stated that for the 

next JAS, they would like to be provided 

with one of the coordinates of a segment’s 

side, particularly the side that overlays a 

road. The enumerators felt that finding the 

road that coincided with a side of the 

segment would help in locating the segment. 

 The enumerators also wanted 

instructions on how to enter and locate 

waypoints. A waypoint is a stored point 

(latitude and longitude) in the GPS receiver. 

The receiver will display the direction and 

distance to this stored point. This would 

provide enumerators with the ability to enter 

the coordinates of a segment’s centroid and 

then have the receiver calculate the distance 

and direction to the centroid. The WA FO 

and RDD staff decided to instruct the field 

enumerators only on the basic functionality 

of the GPS receivers first and perhaps next 

year introduce more advanced topics like 

waypoints. 

 Finally, if GPS receivers were to be 

adopted for the June Area Survey, perhaps 

requiring the enumerators to use their GPS 

receivers for at least verification of their 

location to that of the segments’ might be 

worthwhile. 

8. COST - BENEFIT ANALYSIS 

A cost/benefit analysis was 

conducted to determine if using GPS 

receivers for the June Area Survey is 

practical and cost efficient. 

 The WA FO already had 34 GPS 

receivers from an earlier research project 

involving ARMS II. Miscellaneous supplies 

(batteries, paper, printing costs, etc) totaled 

$50. Enumerator training cost $160. Also, 

one hour of a statistician’s time was needed 

to prepare and conduct the training at the 

JAS Enumerator Workshop. 

 Hence, the total additional “out of 

pocket” cost of using GPS receivers was 

$210 and one hour of a statistician’s time. 

Table 2, located on the following page, 

displays the total costs of using GPS 

receivers for the JAS. 
6 

Table 2: Research Project Expenses 

Item Details Total Costs 

34 GPS Receivers1/ Re-used receivers from ARMS Phase II Study. 0 

Miscellaneous Supplies Batteries, paper, etc. $50 

Enumerator Time & Mileage No additional time or mileage recorded. 0 

Enumerator Training 

(salary & benefits) 2/

39 enumerators, each receiving 20 minutes of 

GPS training. $160 

WA FO Staff One hour for preparation and training of 

enumerators. N/A 3/

Research Project’s Total Cost $210 

1/ If GPS receivers needed to be purchased, the cost for this item ($150 per unit) would have totaled $5,100. 

2/ All enumerator costs were based on each enumerator’s actual time and salaries. The average salary of the 

 enumerators was $10.14 per hour. The average salary and benefits of the enumerators (using NASS’ formula 

 of (salary*1.0763)*1.11) calculates to $12.11 per hour. 

3/ Staff salaries and associated benefits expenses were absorbed by the field office. 

 

 The benefits of using GPS receivers 

for the June Area Survey are difficult to 

equate to an actual dollar value. The eight 

instances that the enumerators stated they 

used the receivers to locate segments are a 

definite benefit. However, the improvement 

in data quality or reduction in enumeration 

time in trying to locate the segment was not 

able to be measured. Also, the seventeen 

times the receivers were used to verify that 

the enumerators were in the general vicinity 

of their segments basically made the 

enumerators feel more confident. This 

benefit also could not be tied to a dollar 

value. 

 The GPS receivers can also be used 

for other surveys (ARMS II and Wheat 

Objective Yield). 

 Hence for the WA FO, which 

already had GPS receivers, this was an 

economical opportunity to possibly improve 

data quality and save on enumeration time. 

For states that do not have GPS receivers, it 

would have to be decided whether the $150 

cost per receiver is practical. 

9. CONCLUSION 

 Using handheld GPS receivers for 

the June Area Survey is practical for field 

offices already having GPS receivers since 

the additional cost is minimal. As the 

enumerators’ GPS skill level increases, they 
7 

will be able to enter and locate waypoints 

which should make the receivers more 

useful for the June Area Survey. 

 The WA FO and RDD will continue 

to explore new ways to utilize the GPS 

receivers to improve data quality and/or 

improve the efficiency of data collection. 

10. REFERENCES 

Gerling, Michael. 2005. “Using Global 

 Positioning Receivers for Phase II of the 

 Agricultural Resource Management 

 Survey.” RDD-05-04, United States 

 Department of Agriculture, National 

 Agricultural Statistics Service. 
8 

APPENDIX A – Enumerator Feedback Form 

June Area Survey - Global Positioning System Research 

Project 

Enumerator - Feedback Form

Enumerator ID 

Segment Number 

1. Was the GPS receiver used in locating the segment or in

verifying that you had found the segment? 

~ Yes 

Was the receiver helpful? Save any time? 

Please elaborate: 

~ No 

Please elaborate: 

 

OVERALL COMMENTS on the GPS Receiver 
9 

APPENDIX B – Instructional Handout 

Overview and Field Enumerator Instructions on Using 

Garmin Global Positioning System Receivers 

for the June Area Survey 

 United States Department of Agriculture 

 National Agricultural Statistics Service
10 

Table of Contents 

Introduction .......................................................................................................... 1 

The Research Project .......................................................................................... 2 

What is GPS? ....................................................................................................... 3 

Overview of the Garmin GPS (Model No. 72) ....................................................... 4 

Interface Keys .................................................................................................... 5 

GPS Receiver Instructions ..................................................................................... 6 

Appendix A - Initializing the GPS Receiver .......................................................... 10 

Appendix B - Format Adjustment of the Location Box ........................................... 11 

Appendix C - Installing the Batteries........................................................................ 14 
11 

Introduction

The Research and Development Division and the Washington Field Office (WA FO) are conducting a 

research project on using handheld Global Positioning System (GPS) receivers for the June Area Survey. 

Currently, field enumerators use a combination of county-highway maps and aerial photos to reach the 

designated land areas (segments) outlined on the aerial photos for enumeration. 

In some cases, there are no road signs and the geography of the land is so similar that determining, where 

a particular segment is, can be very difficult for the enumerator, and sometimes an enumerator may collect 

information for the wrong land area. This costs NASS in field enumeration time and data quality. 

Hence, the research project=s primary goal is to see if GPS receivers can assist enumerators in locating 

the segment. 

1 
12 

The Research Project

Thirty three Washington FO field enumerators have been be provided with a handheld GPS receiver. This 

should provide most enumerators working the June Area Survey with a receiver. 

For all 267 segments, the centroid or (center point of the segment) will be provided. The field enumerators 

will use their GPS receivers to verify that they have reached the land area to be enumerated. 

The receiver will not help the enumerator determine where the boundaries of the segment are but rather 

will provide the enumerator with another way to verify that they are in the general vicinity of the segment. 

Naturally, if the receiver=s coordinates matches those of the segment=s centroid then the enumerator is 

inside the segment. 

The enumerators will also be supplied with a form to record their use of the GPS receivers and if the GPS 

receiver was helpful or not. 

2 
13 

What is GPS?

GPS stands for Global Positioning System. This system is comprised of at least 24 satellites that orbit the 

earth. These satellites transmit signals to global positioning system equipment on the ground, like the 

GPS receiver that each of you have been provided. 

The GPS receiver acquires signals from these satellites. Thus, the receiver requires an unobstructed 

view of the sky. The GPS receiver is able to determine the location of the satellites since this information 

is included in the satellites= transmissions. Next, the receiver determines the distance it is from each 

satellite. Finally, (without getting too technical), the receiver is able to determine where it is actually 

located on the Earth within a certain amount of accuracy. 

The receiver will display its location in latitude and longitude coordinates. Latitude measures the distance 

North or South from the Equator while longitude measures the distance East and West from the Prime 

Meridian. 

A common use of these devices is for hiking. Hikers utilize these receivers to trace their trail or to mark a 

unique location that they would like to return to. 

Hence, a GPS receiver is not a remote control for the television but rather a sophisticated electronic 

device that can tell the user where he/she is (within 50 feet), speed of movement, which way North is, and 

even the distance to a particular point of interest. However, for this research project, the receivers are to 

be used as another tool to help the determine the location of the segment. The next few pages will 

discuss the GPS receiver and what you will need to do to successfully use the device. Welcome to the 

World of Global Positioning. 

3 
14 

Overview 

of the 

Garmin GPS (Model No. 72) 

 Internal Antenna 

Below is a general overview of the receiver that you have been provided. 

 

4 
15 

Interface Keys

POWER Used to turn the unit on and off. To turn the unit off, press the POWER key and hold 

 it. The POWER key is also used to display the adjustment window for the back light 

 and contrast. To activate the back light/contrast adjustment window, press and 

 release the POWER key. 

PAGE Cycles through the five main display pages in sequence. 

MENU Used to display the page option menus. If pressed twice, the Main Menu will be 

 displayed. 

 

ENTER Used to confirm a selection. 

QUIT To cycle through the five main pages in reverse sequence. The QUIT key will also 

 end an operation in progress and display the previous page. 

ROCKER Located in the center of the keypad, is used to control the Up/Down and Left/Right 

 movement of the cursor on the display pages and during data entry. 

GOTO, IN, and OUT keys will not be needed for this study. If additional information is needed 

on these keys please see the provided Owner’s Manual. 

5 
16 

GPS Receiver Instructions 

Use these instructions to verify that you have found the selected segment. 

Step 1: Press the POWER key to turn on the GPS receiver. 

Step 2: A Warning screen will appear. Press the PAGE key and wait for the unit to acquire the 

satellites (up to five minutes). For best results, the receiver=s internal antenna (Page 4)

should be facing up at the sky.

Step 3: The GPS Information page showing the location coordinates should appear. The 

screen should look similar to the one shown below. 

 N 37E 45' 27.3" 

 W110E 41' 31.4"

Note: If the GPS Information page does not appear, press the PAGE key to cycle through the five main

pages of the device. 

6 
17 

Step 4: Verify that the Location box is showing degrees, minutes and seconds. An easy 

way to check this is to look at the latitude coordinate and make sure that it has a " after 

the last number. 

The Location box displays the latitude (N for North) and the longitude (W for 

West) of where the receiver actually is. 

In Step 3, the GPS Information Page displayed the following location: 

 N 37E 45' 27.3" 

 W110E 41' 31.4"

N 37E 45' 27.3" is read as: 

 37 degrees, 45 minutes and 27.3 seconds North. 

W 110E 41' 31.4" is read as: 

 110 degrees, 41 minutes and 31.4 seconds West. 

If the Location box does not display the coordinates in this format, please go to 

Appendix B to re-format your GPS receiver. 

Step 5: Look on the back of the aerial photo for the label containing the coordinates of the 

segment=s centroid. 

Example is shown below: 

Segment 101 

LATITUDE LONGITUDE 

N

 42 . 17 . 25 W 110 . 39 . 12 

 dd mm ss ddd mm ss

7 
18 

Step 6: The goal is to have the latitude and longitude coordinates of your GPS receiver get close 

enough to those of the segment so that you can use the aerial photo and countyhighway map to determine where the segment is. Walk around with the GPS receiver 

and see how the seconds change first, next minutes, and finally the degrees. Walking 

North and South affects latitude, while walking West and East affects longitude. 

Compare the latitude and longitude coordinates provided on the GPS receiver with those 

of segment=s centroid. 

The coordinates will more than likely be different so you will first need to determine how 

far away you are by looking at degrees, minutes and then seconds. 

 

The following distance conversions will help you determine how many feet or miles away 

you are from the segment=s centroid. 

Latitude 

1 degree = 69 miles 

1 minute = 1 mile = 5,280 feet 

1 second = 100 feet 

Longitude 

1 degree = 47 miles 

1 minute = 3/4 mile or 4150 feet 

1 second = 70 feet 

Hence, one degree of latitude is about 69 miles while one second is about 100 feet. 

Depending on the distance, you must determine whether to walk or drive in the direction 

that brings you to the segment. An example is provided on page 10. 

Step 7: Locate the segment and proceed with your normal enumeration procedures.

Step 8: Complete the AJune Area Survey - GPS Receiver Usage: Feedback Form@. 

Important: Please carry an extra set of AA batteries with you. When the batteries are running low, a 

low battery warning will appear that will not disappear unless new batteries are installed. 

See Appendix C for instructions on how to install a new set of batteries.

8 
19 

Example of Using the GPS Receiver for the June Area Survey 

An enumerator wants to verify that he/she is in the general vicinity of the segment and therefore 

powers on his/her GPS receiver. The receiver displays the following coordinates: 

 GPS Receiver 

 N 42E 17' 26.1" 

 W 110E 39' 41.4"

Next, the enumerator looks at the coordinates displayed on the back of the segment=s aerial 

photo. 

 Aerial Photo Label for Segment 140 

LATITUDE LONGITUDE 

N 42 . 25 . 24 W 110 . 39 . 12 

dd mm ss ddd mm ss

The enumerator first focuses on latitude and notices that the first set of numbers is identical at 42 

. However, the second set (minutes) is different. Comparing the minutes of the GPS receiver to 

those for the segment=s centroid, the enumerator calculates 17 minus 25 = 8 minutes. Hence, the 

enumerator is approximately 8 miles south of the segment=s center. 

Next, the enumerator looks at longitude, the first two sets of numbers are identical. However, the 

third set is different. 41 - 12 = 29 seconds. (Ignore the tenths of a second displayed on the GPS 

receiver.) This means that the enumerator is about 2,000 feet (1/3 of a mile) west from the center 

of the segment. 

Therefore, the enumerator is southwest of the segment=s centroid and should drive about 7 miles 

north and using the map, photo, and GPS receiver determine if he/she has reached the segment. 

Remember: The goal is NOT to reach the segment=s centroid but to use the GPS receiver 

as another tool to assist in finding the segment.

9 
20 

Appendix A 

Initializing the GPS Receiver

The Washington SSO should have initialized your receiver. However, if it is unable to locate the 

satellites, please do the following steps.

Step 1: Take the unit outside where it will have an unobstructed view of the sky and turn it on by 

pressing the POWER key.

Step 2: Press the PAGE key to bypass the Warning Screen. 

Step 3: If the receiver is unable to acquire enough satellites an options page will appear.

Step 4: Using the ROCKER key, select >New location= then press then ENTER key. 

Step 5: Next, select >Automatic= and press the ENTER key. 

This will allow the unit to continue initializing. This selection will force the unit to search

for all satellites. It may take a little longer for the unit to become operational using this

method. 

A screen that looks similar to the one displayed below should appear. If not, please repeat the above

process and if this doesn=t work, call the office for additional instructions. 

10 
21 

Appendix B 

Format Adjustment of the Location Box

The office should have pre-set the format of the Location box for your GPS device. However, if you

notice that the format is no longer in degrees, minutes, seconds, then you need will to re-set the location 

field from hdddE mm.mmm= to hdddEmm=ss.s@. Having the device display in the latitude and longitude

coordinates correctly is critical to having a successful research project. The following steps will guide 

you on how to re-set the Location box=s format. 

Step 1: Press the POWER key to turn the unit on and then press the PAGE key. You should be

at the screen shown below.

Step 2: Press the MENU key. The following screen should appear. 

11 
22 

Step 3: Press the MENU key again and the Main Menu should appear. 

Step 4: Using the ROCKER key, rocker down to the Setup option and press the ENTER key. 

The screen shown below should now appear. 

Step 5: Using the ROCKER key, rocker over to the right to the Location tab. 
23 

Step 6: Using the ROCKER key, rocker down once to the Location format and press the ENTER

key. 

Step 7: Using the ROCKER key select hdddEmm=ss.s@ and press the ENTER key. 

Step 8: Press the MENU key three times to return you to your original screen. You should see 

your new location format. 

13 
24 

Appendix C 

Installing the Batteries

Step 1: Remove the Battery Cover by turning the D-ring 1/4 turn counter clockwise and pulling

the cover loose. 

Step 2: Check the battery polarity with the molded diagram in the battery compartment and install 

the two AA batteries inserting the end toward the spring first. 

Step 3: Re-install the Battery Cover by reversing Step 1. 

14 
25