Recreational Geocaching: The South East Queensland Experience

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Refereed Paper Submission to 2001 - A Spatial Odyssey Australian Surveying Congress - Brisbane September 2001. Recreational Geocaching: The Southeast Queensland Experience ROBERT WEBB School of Design & Built Environment Queensland University of Technology

Keywords: GPS, Point Positioning, Geocache, Recreational Surveying ABSTRACT Recreational Geocaching is a new 21st century recreation and adventure game that came about as a result of the improving accuracy of electronic Global Positioning System (GPS) devices. With improved positional accuracy, of the order of five to ten metres, hand-held GPS's now allow unskilled users the ability to find geographic locations with precision and repeatability. With this new ability, people can now place geocaches in interesting places so that others can enjoy the challenge of finding them. In the rapidly developing sport of Recreational Geocaching, the Internet is used as a medium for the distribution of geocache locations. Web-sites have now been set up to support this new activity. The Internet allows communication between the geocacher and those searching for the geocache. Posted on the Internet along with the geographic coordinates, are clues, pictures, and other information about the geocache. This paper describes the recent history of recreational geocaching, some basic rules of the adventure game, some inclusions and exclusions of a cache, and adventure variations. An additional description of the survey methods used to confirm positional location and repeatability is included along with some surveying experiences around the SouthEast Queensland region.

INTRODUCTION Since the removal of Selective Availability (SA) from the Global Positioning System (GPS), recreational and professional users of GPS now have improved positional accuracy in the order of five to ten metres horizontally. Hand-held GPS units now allow unskilled users the ability to find geographic locations with precision and repeatability. With this new ability, people can now become involved in recreational pursuits such as the degree confluence project and/or recreational geocaching. These sports are in their infancy in Australia but are growing in popularity. In the rapidly developing sport of Recreational Geocaching, the Internet is used as a medium for the distribution of geocache locations. Web-sites have now been set up to support this new activity. The

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Internet allows communication between the geocacher and those searching for the geocache. Posted on the Internet along with the geographic coordinates, are clues, pictures, and other information about the geocache. QUT Surveying students have been involved in both the placement and visitation of physical points through the recreational geocaching.com sport, and the location and visitation of virtual points based on the degree confluence project. Our future surveying professionals have much to offer to these spatial information based sports based on GPS technology and Internet communications.

HISTORY OF THE GEOCACHING SPORT The word Geocaching (pronounced geo-cashing) syllabised is GEO for geography, and CACHING for the process of hiding a cache or treasure. A cache in computer terms is information usually stored in memory to make it faster to retrieve, but the term is also used in hiking/camping as a hiding place for concealing and preserving provisions. The GPS Stash Hunt or Global Positioning Stash hunts are early names of the standard game Geocaching. When the GPS signal degradation called Selective Availability (SA) was removed by the US Clinton Administration May 1st, 2000, it opened up the possibility of games like this one. On May 3rd, a container of goodies was hidden by a gentleman outside of Portland, Oregon - in celebration of the removing of SA. By May 6th the cache was visited twice, and logged in the logbook once. Mike Teague was the first to find the container, and built the first web-site to document these containers and their locations that were posted to the sci.geo.satellite-nav newsgroup. Paul Edwards planted Australia's first geocache on May 18, 2000 at Lane Cove near Sydney. In July of 2000, Jeremy Irish found Mike Teague's web site and found his first cache outside of Seattle, Washington. Recognising the potential of the game, Jeremy approached Mike Teague with a new site design, used the name Geocaching, and developed a new web-site adding virtual logs, maps, and a way to make it easier to maintain caches as the sport grows. The site was alive for a while, but the official torch was passed to Jeremy on September 6 on the same year. Since the launch of the web site, the Geocaching sport has grown to 3695 active caches in 59 countries (as at 15 July 2001) (Irish 2001a). There are now many variations of the game, including virtual caches, offset caches, puzzle caches, multi-stage caches. New ideas and new games crop up every other month. From its inception, Geocaching.com has been developed and maintained by Jeremy Irish, with the assistance of geocachers around the world. The official web site for Geocaching is www.geocaching.com. Geocaching is an entertaining adventure game for GPS users. Participating in a cache hunt is a good way to take advantage of the features and capability of a hand-held GPS unit. The basic idea of this sport appears to have individuals and organisations set up caches all over the world and share the locations of these caches on the Internet. GPS users can then use the location coordinates to find the caches. SOME BASIC RULES OF GEOCACHING Geocaching is a relatively new phenomenon and a world wide sport in its infancy. Therefore, the rules are very simple at this stage and variations on the basic theme is encouraged: 1. Enjoy the challenge of finding the cache 2. Take something from the cache

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3. Leave something in the cache 4. Write about it in the logbook 5. Note your comments on the web-site. Variations on the main theme are encouraged and the above rules are very flexible. According to Irish 2001a, some examples of game variations include Offset Caches - They're not found by simply going to some coordinates and finding a cache there. With the offset cache the published coordinates are that of an existing historical monument, plaque, or even a benchmark that you would like to have your cache hunter visit. From this site the cache hunter must look around and find offset numbers stamped/written in or on some part of the marker site, or continue based on instructions posted to geocaching.com Multi-caches - The first cache gives coordinates (or partial coordinates) to the next location, or multiple caches have hints to the final cache. Virtual caches - A cache is actually an existing landmark, such as a tombstone or statue. You have to answer a question from the landmark and let the "cache" owner know as proof that you were there. The duration of existence of individual caches depends on the owners' maintenance ability or it's impact on the environment and the surrounding areas. Caches could be permanent, or temporary. It's up to the cache owner to periodically inspect the cache and the area to ensure that impact is minimal, if not non-existent. Another useful Internet resource is that compiled by Hall (2001) called Buxley's Geocaching Waypoint Internet page. The following maps provide a snapshot of the spatial distribution of geocaches on a World scale and at the Australian region.

Figure 1 World Map of Spatial Distribution of Geocache

QUT SURVEYING GEOCACHING EXPERIENCES QUT Surveying students have been involved in both the placement and visitation of physical points through the recreational geocaching.com sport in the SouthEast Queensland region. QUT students

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based their difficulty and terrain rating for a cache on information derived from a NSW group called !Ideology Geocaching. There are two differing ratings systems for each cache: difficulty and terrain. For the difficulty aspect, we prefer Markwell's Difficulty Guidelines v1.1, which are: Rating 1. A ten-year-old could probably figure it out without too much difficulty Rating 2. An average adult would be able to find this in about 30 minutes of hunting Rating 3. An experienced Geocacher will find this challenging, and it will take up a good portion of an afternoon. Rating 4. An extreme challenge for the experienced Geocacher. May require in-depth preparation or cartography/navigational skills. Rating 5. Mensa or equivalent For the terrain aspect, the preferred rating utilises the Scout Scale: Rating 1. Handicapped accessible Rating 2. Suitable for small children; generally on trail Rating 3. Off trail; requires some risk of getting scratched, wet, or winded

Rating 4. Off trail; likelihood of getting scratched, wet and winded. Probably requires special equipment (boat, 4WD, etc.). Rating 5. Requires specialised equipment and knowledge/experience (rock climbing, SCUBA, etc.).

Figure 2 Map of Australian Goecache Locations

The geodesy students of the undergraduate Bachelor of Surveying program at QUT have been participating in establishing some nine Geocaches in the SouthEast Queensland region. The spatial positional information provided are not about squeezing centimetre level accuracy out of the

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locations, but more about providing a reliable position that is close enough to allow a visual connection to be made to a cache container. This task has proven valuable as a learning tool in using basic hand-held GPS, waypoint datums, introduction to navigational information and Internet communications for this high technology recreational sport.

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Students working in groups of two undertook the following applied learning approach: Step One: To visit and read the material on Geocaching Dot Com. This includes the origin of the sport, examining the frequently asked questions pages, searching for nearby existing caches (if any), and sampling the style of comments and feedback reporting for a few sample geocaches. Step Two: To research a cache location with consideration given to location, location, location!!! Issues of concern include will it be easy to get to but far enough away from general public traffic routes that non-players of the sport will not stumble over or plunder the contents. The challenge of getting to the cache was broadly defined, and those students not adhering to the official guidelines have resulted in the cache being destroyed after a short time (refer line 1 of table 1). The issue of non-placement on private lands or in environmental sensitive areas is emphasised and at times resulted in the most time consuming research component. Step Three: To prepare the cache itself ready for placement. A cache can come in many forms but the compulsory item should be the logbook. The logbook contains information from the founder of the cache and notes from the cache visitors. The logbook can contain much valuable, rewarding and entertaining information. A sample letter can be downloaded from the geocaching.com web-site for inclusion. Issues arise relating to the container itself, is it to be buried, hang from a cliff-face or tree, or be susceptible to water (salt) or fire damage? What else to include in the contents, costs, novelty value etc. Ideas have included read-write CD-ROMs, comic books, cheap toys, disposable camera, gold-bars, GPS batteries etc. Since this sport evolved in America, some nasty incidents have occurred (not yet in Australia) with a minority of caches. Therefore the contents should not contain food, drugs, alcohol or explosives. Step Four: Placement of the Geocache and using a hand-held GPS to obtain a reliable averaged position in good geometric conditions. Many hand-held GPS units can use an averaging function for waypoint collection, otherwise an 8-point approaching directional averaging technique should be used with the in-built antenna. An external GPS antenna is highly recommended as it provides greater operational stability and flexibility over an internal antenna. Assuming the GPS receiver has the capability to accurately compute the location to +/- one least significant digit, the resolution of the 3 common formats (with respect to 1 degree) is as follows: HDD.DDDDD gives 1 part in 100000 HDD MM.MMM gives 1 part in 60000 (only 60 minutes per degree) HDD MM SS.S gives 1 part in 36000 H=hemisphere; D=degrees; M=minutes; S=seconds. The first format including decimal degrees provides the greatest resolution. Step Five: Reporting the Cache using the on-line form or e-mail service of the details for reporting onto the official web-site. Consideration needs to be given to a unique name for your cache, the rating associated with difficulty and terrain, and contact information. The submitted details take a few days before publishing onto the site. Step Six: Maintain the Cache. Once you place the cache, it is your responsibility to maintain the cache and the area around it. You'll need to return as often as you can to ensure it is not impacting the area, and check that it is in good condition. Are other visitors disrupting the landscape in any way? If you have concerns about the location you may need to move or remove it from the area. Comments from visitors can be accessed from the main cache pages, with some automation via email attention to new visits and/or comments.

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Table 1 Table of QUT Surveying Geocaches established til June 30 2001

Cache NAME

WGS-84 Position Latitude

WGS-84 Position Longitude

Descriptive Location

Difficulty

Terrain

Placement Time (all 2001)

Success Visits @ June 2001

Drewgong, moogsie and spider Homer Laroon

27o31.187S

153o1.357E

Dutton Park

1

1

Mid May

27o28.080S 26o42.87S

152o57.605E 152o52.46E

2 2

3 1.5

Early May Mid April

Mozziebait

27o8.16S

153o2.32E

3.5

4

Mid April

0

Geo-cache M+T+S

27o45.93S

153o24.83E

3

4

Mid April

1

Brown Lake

27o29.537S

153o25.732E

2

2

Mid April

0

Dandy

27o29.46S

152o47.344E

3.5

3.5

Late March

1

HydroCamp Glasshouse

28o1.278S

152o32.652E

3.5

3

Mid March

1

26o53.886S

152o56.088E

Mt Cootha Borumba Dam On an island mouth Caboolture River On an island near Jumpin passage On North Stradbroke Island Lake Manchester Moogerah Dam One of the Glasshouse mountains

3 (destroyed early June) 1 3

2

3

Early March

3

A secondary learning aim is to verify the status and location of these geocaches, and where appropriate, use differential GPS techniques to refine the precision of caches. A tower antenna mount (9metres) may be used in some circumstances as future geodesy students visit and refine the cache specifications.

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THE DEGREE CONFLUENCE PROJECT

Figure 3 Main Logo of Degree Confluence Project

The goal of the Degree Confluence project is to visit each of the latitude and longitude integer degree intersections on the world, and to take pictures at each location. A narrative along with the pictures describing the adventures it took to get there are then posted on the projects web-site. This project was started by Alex Jarrett, (USA) in February 1996 based on the idea of visiting a location represented by a round number such as 27o00'00"S 153o00'00"E and creating an organised sampling of the world. The curiosity questions posed by Jarrett included "What would be at this location? Would other people have recognised this as a unique spot? Another reason was that y friend managed to convince me to buy a GPS and I had to come up with something to do with it. I also hoped to encourage people to get outside, tromp around in places they normally would never go, and take pictures of it. I visited several confluences of my own and posted them to my personal web-site. Before long others found the site and visited confluences of their own, and it just snowballed from there." (Jarrett 2001b Section 1.2.) The official datum for the project is WGS84. The accuracy of the confluence must be to within 100metres. With the removal of selective availability, the challenge of obtaining a position better than 100 metres with a code based hand-held receiver is greatly improved. Jarrett further explains that "It has been calculated that there are 64,442 latitude and longitude degree intersections in the world (counting each pole as one intersection). Of these, 47,650 meet the goals of the project after removing many confluences near the poles. Of this group, about 12,000 are actually on the land and should meet the requirements for primary confluences."

CONFLUENCE POLES PROBLEM According to Jarrett (2001b), "the distance between latitude lines is always 68.9miles (110.9 km) apart, regardless of position. The distance between longitude lines varies depending on the latitude. At the equator (0 degrees latitude), longitude lines are 69.2 miles (111.4 km) apart. At 89 degrees latitude, one degree from the north or south pole, the lines are 1.2 miles apart. This skews the sample sharply to the poles, as the table below shows.

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Recreational Geocaching: The South East Queensland Experience

Longitude Distances 0° 69.2 mi. (111.4 km) 10° 68.2 mi. (109.8 km) 20° 65.1 mi. (104.8 km) 30° 60.0 mi. (96.6 km) 40° 53.1 mi. (85.5 km) 50° 44.5 mi. (71.6 km) 60° 34.6 mi. (55.7 km) 70° 23.6 mi. (38.0 km) 80° 12.0 mi. (19.3 km)

15° 25°

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5° 69.0 mi. (111.1 km) 66.9 mi. (107.7 km) 62.8 mi. (101.1 km) 35° 56.6 mi. (91.1 km) 45° 48.8 mi. (78.6 km) 55° 39.6 mi. (63.8 km) 65° 29.3 mi. (47.2 km) 75° 17.8 mi. (28.7 km) 85° 6.1 mi. (9.8 km)

My proposal for a solution to the problem is to skip confluences when the distance between them falls below 2/3 of the distance at the equator (46.1miles/74.2 km). This begins at 49 degrees latitude (which happens to be a large section of United States/Canadian border). At 49 degrees, the distance between longitude lines is 45.4 miles (73.1 km). Every third confluence will be skipped (when the longitude modulo 3 equals 2) until the average distance falls below 2/3 of the distance at the equator. This happens at 64 degrees, after which every other confluence will be skipped (longitude modulo 2 equals 1), and so on. At 89 degrees, only ten of the possible 360 confluences will be visited, and at 90 degrees, only one will be visited. This also reduces the total number of confluences that need to be visited significantly. The omitted confluences are still valid confluences, and will be posted if visited, but are not part of the primary goals of the project. A confluence is primary if: ♦ It meets the criteria outlined in the poles problem section. Because longitude lines are closer together as the latitude increases, we've decided to drop some confluences at 49° latitude and greater. ♦ It's on land, or if in a body of water, within sight of land, so that, on a clear day, discernible land features can be recognised. All other confluences are defined as secondary. They will be accepted if visited but are not part of the primary goals of the project." (Jarrett 2001b) The web-site explains that in some cases, attempts within 200 metres may be accepted as successful if extraordinary circumstances prevent access to a closer point. This has happened as 33N/97W, near Lewisville, Texas, USA, where a Raytheon military electronics factory prevented closer access because of the risk of arrest. The GPS position used should be derived from an averaging method. The final digital photograph of the location must exceed 600 by 400 pixels in resolution, with a 16bit or greater colour depth. The web-site information suggests including 2 to 5 pictures from or of the confluence spot with no people in the pictures, and optionally, 1 to 4 pictures with the confluence visitors or the journey to the confluence. It is also highly desirable to take a picture of the GPS reading the confluence location. The diagram below represents the location of successful confluence visits (at June 2001). Australia has 704 possible degree confluences, with some 74 having been visited thus far. Queensland has 145 degree confluences, with some 14 having successful visits.

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Figure 4 Spatial Distribution of Successful Australian Confluences

QUT PROJECT EXPLORES SOUTHEAST QLD CONFLUENCES Figure 4 Spatial Distribution of Successful Australian Confluences

Focusing on the SouthEast Queensland region on the map above, the current status of the primary degree integer confluences has been successfully completed by others. A medium term QUT surveying project is to mirror the objectives of the degree confluence project to visit the 30minute confluences (stage one), and then to populate the recreational GPS efforts using the 15minute confluences (after stage one). The operational plan is to visit two confluences in the similar locations on the following datums: ♦ WGS84 datum (approximating GDA94) ♦ AGD84. Once an approximate location for these two positions has been identified, owners permission(s) in writing sought and suitable reconnaissance undertaken, a temporary ground mark will be placed in a suitable nearby location. From this groundmark, a regional GPS solution will be undertaken using RINEX data collected using Trimble 4000 and 4800 dual-frequency survey-quality GPS receivers and the AUSLIG on-line GPS processing techniques with connection to the Australian Fiducial Network (AFN). This will then allow connection and possible placement of suitable monumentation of the confluence location. A final horizontal position better than 1 metre is anticipated, pending physical obstruction(s). It is guesstimated that only 50% of available locations in the study area will be able to meet the criteria for this project, pending issues of permission's, physical obstructions etc.

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Figure 5 Part of the visualisation tools being developed for this project

The diagram above is part of the confluence visualisation tools being developed at QUT: Design and Built Environment as an aid to grid locations and access. The backdrop map images use the AUSLIG product GEODATA Raster 250K. The SouthEast Queensland region is defined by extents as between longitudes 151o30'00"E and 153o30'00"E, and between latitudes 25o00'00"S and 28o30'00"S. The efforts of students is recognised and acknowledged in undertaking reconnaissance for the grid intersections in this region. The driving time to 30minute confluences is generally less than three hours from central Brisbane. The provision of survey-quality Trimble GPS equipment used in this Figure is 5 Part of the visualisation tools developedprogram for this project project acknowledged through thebeing educational provided by Trimble Navigation Australia and Herga Ultimate Positioning Group. CONCLUSIONS The rapidly evolving technologies of global positioning systems and the Internet is opening up new and exciting spatial odyssey adventures. The surveying profession is well placed in terms of providing leadership for spatial information data gathering and dissemination of these new applications. The old real estate saying of location, location, location! should perhaps now be replaced by the new spatial technologist saying of position, position, position!!! REFERENCES AUSLIG, 2000, GEODATA Raster 250K (CD2), based on the 1:250,000 scale topographic mapping sheets for Sh5603Brisbane and Sg5614Ipswich. These map images are used solely for educational and research purposes. Hall, E., 2001,"Buxley's Geocaching Waypoint Internet Page", available on-line Internet http://www.brillig.com/geocaching/ (accessed July 2001) Ideology Geocaching, 2001, "!Ideology Geocaching Internet Page", available on-line Internet http://ideology.com.au/geocaching/ (accessed July 2001) Jarrett A., 2001a, "The Degree Confluence Project: Index", available on-line Internet http://www.confluence.org/index.php (accessed July 2001) variable pp. Jarrett A., 2001b, "Degree Confluence Project: FAQ", available on-line Internet http://www.confluence.org/faq.html (accessed July 2001) 5pp. Markwell A., 2001, "Markwell's Geocaching Difficulty Guidelines v1.1", Cache Difficulty Ratings -

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The GroundSpeak Forums, available on-line Internet http://forums.groundspeak.com/ubb/Forum2/HTML/000331.html (accessed July 2001) Irish J., 2001a, "Geocaching - The Official GPS Cache Hunt Site", available on-line Internet http://www.geocaching.com/ (accessed July 2001) Irish J., 2001b, "Geocaching - Frequently Asked Questions", available on-line Internet http://www.geocaching.com/faq.asp (accessed July 2001) 1.Presenter's name, Address, Fax, Phone and E-mail Address

Robert Webb School of Design and Built Environment Queensland University of Technology GPO Box 2434, Brisbane Qld 4001 Fax: 07 3864 1809, Phone: 07 3864 2434, E-mail: [email protected] 2.Co-authors' Names (if applicable) NOT APPLICABLE 3.Title of Presentation (20 word limit)

Recreational Geocaching: The SouthEast Queensland Experience. 4.Type of Presentation (Paper, Oral Presentation, Poster, Workshop) PAPER 5.Topic

Topic/Theme is Surveying and Recreation (GPS)

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