DaveD

I have no idea how those got to the GC database but they're not in the NGS database.

Where are you seeing recoveries from 1930 & 1937?? JB1913 HISTORY - Date Condition Report By JB1913 HISTORY - 1971 MONUMENTED NGS JB1913 HISTORY - 1971 GOOD NGS JB1913 HISTORY - 20010501 GOOD NGS

1960 - JB1836 1970 - JB1913 1980 - JC1679 1990 - HC1137 2000 - AJ3110

Today the town of Plato, Missouri was officially named as the 2010 Center of Population by the U.S. Census Bureau. Earlier this week a small team representing Census, the National Geodetic Survey and the Missouri Department of Natural Resources performed the preliminary reconnaissance to set a commemorative marker. The mark is identitical in design to the 2000 Center of Population marker set in Edgar Springs, MO except that it is 12" in diameter and made of stainless steel. The marker will be embedded in a pillar of Missouri Red Granite and set in Plato in conjunction with a dedication ceremony being planned for late April or early May. The mark will then be positioned and added to the NGS database as part of a regional GPS network by MODNR. Stay tuned for the announcement of when the dedication will be held.

The 2000 Center of Population effort was a project of the National Geodetic Survey in cooperation with the American Congress on Surveying and Mapping and the various state professional surveyors associations. Other than computing the centroid values Census had nothing to do with that program. There are no plans for a similar 2010 project. The Census Bureau in partnership with the National Geodetic Survey will set the 2010 National Center of Population mark. The large (12") commemorative disk has already been made and is only waiting for Census to complete the final geographic computations and the organization of a reconnaissance and mark setting effort. Census and NGS are planning a dedication ceremony but no official date has been set at this time.

The National Geodetic Survey and our predecessor agency the U.S. Coast & Geodetic Survey has observed several million individual observations including: triangulation and traverse direction (angle) measurements, high accuracy distances from rods, tapes and electronic (microwave, laser and infrared) measurement system, height differences from leveling, gravity observations and global positioning system vectors. When an data element such as the horizontal position or the orthometric height are designated as "ADJUSTED" that means that the value was determined through a very rigorous analysis of the observations, application of appropriate standard errors and adjustment of these data as part of either a national, regional or local least squares adjustment of the observations. All such observations are maintained by NGS in our database as part of the National Spatial Reference System and are available to the public on demand (we seldom get such requests). The term "ADJUSTED" along with the corresponding order of accuracy provides the user with a level of confidence in the quality of the data element to meet the needs of their surveying/cartographic/GIS applications. We constantly tell users to challenge these data. Many control points are in places effected by a high degree of plate tectonic motion while many, if not most, of the geodetic positions and heights are the result of observtions taken more than 40 years ago and have not been validated by contemporary measurements. Unless a mark has been phyically moved a considerable distance it's not likely that you will detect a significant difference with the resource/recreation grade GPS receivers. The modernization of GPS and development of other constellations such as the Russian GLONASS, European Union GALILEO and Chinese COMPASS will greatly enchance the capability of hand-held devices. Some believe that future receivers may easily achive 10 cm with no augementation (e.g. WAAS, NDGPS).

For kayakbird - I hesitate to change the geographic designation for stations such as you mentioned as we have a general policy to not publish data for passive marks in Canada. If we change the country/county/province designation then they will immediately become unpublishable. I would let sleeping dogs lie.

ArtMan - I would prefer that corrections be sent to me by e-mail -- dave.doyle@noaa.gov. Please provide the PID and what county you think it belongs in, I will do the rest of the reseach. I have reviewed and confirmed the changes posted by tosborn and southpawaz and I have submitted a database change request to the NGS Records Management branch.

Thanks tosborn. I will review these and take the appropriate action.

It must be a quite day for the NGS Records Management team - KV1351 (R 25) has been corrected. Thanks Harry Dolphin for taking the time and effort to help us make the National Spatial Reference System as perfect as possible.

I have validated that KV1351 (R 25) is in Hunterdon instead of Somerset county. I have sent a change notice to the NGS Records Managment Branch. Hopefully they will get to this in short order.

Mike, Give me whatever you have.Sometimes the error can be very obvious and I will easily accept the correction. Sometimes they can be very close and will require more scrutiny. If it's too close to call we'll usually error on the side of what we have published.

I don't know who at NGS would have told you we don't care but that's not true. Whenever a correction for the state or county has been posted to me I review it and if it's legit I have our database team make the correction ASAP. We have made numerous such corrections from this board over the years. Since one of the NGS database retrival options is by county we want to try and make sure that our information is as correct as possible.

A Picture Point (PP), also known as a Photo Control Point or a Photo Identifible Point, is an object that can easily be identfied on an aerial photo (e.g. right angle road intersection, fence corner, corner of a sidewalk etc.) Sometimes that actual geodetic control point will have panels placed around it so that it can be seen on the imagery and act as a PP. PPs are used as references and checks for photogrammetrists to ensure that mosaics of stero images for mapping programs fit together.

The work of Thomas Freeman should be in the archives of the Bureau of Land Management. He worked rather extensively to lay out the Public Land Survey System (PLSS) in Alabama in his role as "Surveyor of the Lands South of Tennessee." The BLM may have information on the marks he set as part of that effort. I regret that it's not likely that many, if any, have been included in the National Spatial Reference System maintained by NGS. You might also try contacting the Alabama Society of Professional Land Surveyors (www.aspls.org)

I think many of feel the same way. Excerpted from the foreward I wrote for the book "Lasting Impresseions" published by Berntsen .http://www.berntsen.com/GoShopping/Surveying/Collectibles/Books/tabid/1778/ctl/ViewProduct/mid/612/itemID/881/Default.aspx "Lasting Impressions is devoted to every surveyor who has climbed that “tough hill,” or cut brush for hours through a snake, mosquito, and chigger invested swamp, to find that called for mark. And for their determination and detective work, have been rewarded by finding that tree stump, brass plug, chiseled square, drill hole, stone or concrete monument, that no one else has seen since the original surveyors left their calling card many years ago. Increasingly, efforts by individuals from the popular past time of geocaching are also playing a significant role in the attempt to preserve and protect these essential components of our national infrastructure. The public may never understand or appreciate the euphoric feeling the cadre of geospatial detectives enjoys. We scrape away decades of dirt and goo to expose the object of our investigations and feel a connection with the pioneers of our national surveying, mapping, and charting history that literally marked the progress of our country. "

Drawing arrows, boxes or circles on pictures for marks that are not easy to see is fine - make sure it's in a contrasting color - yellow usually works well. These kinds of references are also good to use on marks in buildings, bridges or other structures that have been painted over and may be hard to see.

I have been harvesting photos and coordinates from this site for several years to update the NGS database. Since we don't have a dedicated staff to do this I work on it as time allows between various projects. In general the process is subjective. I evaluate the photos to make sure they're clear and provide both good horizon and up close up views - I don't generally take photos with people in them or other obstrutive objects such as those where they've included their GPS receiver in the image. When someone indicates that they've recovered a station I look at the history. If someone has posted a HH position I will usually accept that as an HH2 value. If it differs by more than 10" seconds in any component I have several methods to validate that the HH value is correct. If there has been more than one recovery and perhaps several posters have given their HH values then I will mean them and call the value HH1. Again this is a subjective process, but I think it's worked fairly well. I have captured more photos and updated positions for something like 10,000 stations over the past three years. I think this is a great way to take advantage of the fun that geocachers are having to help us improve the quality of stations in the National Spatial Reference System and enhance the ability of other users to find the marks either for their professional needs (surveying, engineering, GIS etc.) or just the fun of mark recovery.

Don't get too deep into the weeds on this. In the specific case of the station questioned by TillaMurphs, my records indicate that we had a position in the NGS archieves from the U.S. Geological Survey where they had run a geodetic traverse over the station. I took their NAD 27 coordinates and transformed them to NAD 83 and that's what we show on the datasheet. In the order of preference I use NGS observations to Reference Marks from the box score, then any USGS data that may be available and finally hand-held positions that I harvest from this site. In the case of data from this site, if there have been more than one recovery where the bench mark hunter provided coordinates then I will average the values from the various submissions as this provides a bit of redundancy. Remember the intention of HH1 and HH2 is only to improve the values from scaled so that the mark is easier to find for the next person. The difference between NAD 83 and WGS 84 is about 1 m in the horizontal so this falls well within the tolerance for either value and the time required to make any difference is not really worth the effort. If someone wants to submit a survey-grade position for publication to NGS they can use OPUS-DB (database). Thanks to all who put a coordinate in their post. I am often frustrated by some who indicate that the scaled bench mark position is off by several hundred feet and then never provide the coordinates they got.

The designation HH should not be taken literally to mean that someone went to the mark in question with a hand-held GPS receiver, but rather that some form of observation has been made to allow NGS to update a previously scaled value with something that should have more integrity. This could come from several sources: 1. Over the pass several years I have captured almost 10,000 hand-held positions from this site for bench marks with scaled values and had them updated in the NGS database - even though no recovery may have been submitted by the person who recovered the mark. 2. Reference Marks (RMs) for triangulation stations that are also vertical control points and previously had scaled positions usually have sufficient information to determine their coordinates from the data in the "box score" of the datasheet. As time as permitted, I have computed these values and updated the coordinates in the database. This does not require that the mark have been visited. 3. Finally, the U.S. Geological Survey (USGS) during the years that they were actively engaged in field surveys to support their national mapping efforts conducted horizontal surveys on thousands of points. In addition to their own marks they often performed observations to USC&GS/NGS bench marks. Again as time as permitted, I have reviewed the USGS data holdings in the NGS archives and captured their values and updated the NGS database. Since the HH (1 & 2) are defined to assist in the recovery of these marks and not for survey control I have felt that making these data available can be of value to the surveyors and others who rely on the data in the National Spatial Reference System.

The first of the next generation GPS Block 2F-1 was launcher last Thursday (May 27). Among other things this is the first operational SV to provide the 3rd dedicated civil frequency L5. While it will take several years to repopulate the constellation to a point where this enhancement will be noticeable, the not-so-distance future of space-based positioning is looking very exciting.

NGS does not intend to do away with passive marks. What is described in the 10 year plan is our ability to deliver access to the reference system through active stations (CORS) and to provide models such as improved geoid model -- GRAV-D, and tools such as OPUS and OPUS-DB (database) that will allow surveyors to set passive marks when and where they want them, easily connect them to the National Spatial Reference System and be able to archive and share their data. We believe strategy laid out in the plan will allow us to meet these goals.

Without gravity observations there would be no way that NGS (USC&GS) could provide accurate heights (bench marks) for the country. These observations are vital to the proper reduction of leveling observations. They are also an important part of the horizontal component of the reference frame as they help in the determination of what's call the Deflection of the Vertical. This allows for the accurate determination of the relations between the Earth's gravity field and the determination of coordinates on a mathematical reference surface -- the ellipsoid. NGS is currently involved in a historical undertaking to observe gravity from space platforms (GRACE, GOCE), airborne, absolute, marine and relative measurements to form the foundation for a new national vertical datum based purely on gravity data- bench marks from NGS will become a thing of the past. This effort is describe in detail on the NGS web site (http://www.ngs.noaa.gov) and search for GRAV-D (Gravity for the Redefinition of the American Vertical Datum)

foxtrot_xray - that's for letting me know about DL5509, I've forwarded that info along. It appears that there may have been some kind of a strange loading bug when this particular project was loaded into the DB. The scaled values show up on the NGS datasheet retrival page, but not on the datasheet itself. Hopefully we can clear this up real soon. Thanks again.

This is a strange one. I've seen lots of odd things in the database, but this is a new one. I've reported it to the NGS database team and they will correct it shortly. There is a scaled position that shows up when you do a DB retrival -- N275156/W0813529