+geojibby Posted November 9, 2010 Share Posted November 9, 2010 (edited) Hi friends - I'm trying to find Geological/Geodetic Survey of Canada benchmark information to check the "accuracy" of some GPS receivers. I went to the nrcan website, signed up for my free account, and nothing is straightforward or easy (as with most government websites). How can I search for a benchmark number??????? Any help appreciated. Edited November 9, 2010 by geojibby Quote Link to comment
+PDOP's Posted November 9, 2010 Share Posted November 9, 2010 (edited) Once you signed in look for the CSRS Database Request section and select the Go button. The next screen gives you a number of options for searching including Station Unique Number Search. Note that only federal benchmarks are listed in this database and you may have to look elsewhere for provincial benchmarks. If you can describe the benchmark others here might be able to help you more. Edited November 9, 2010 by PDOP's Quote Link to comment
+mwellman Posted November 10, 2010 Share Posted November 10, 2010 Hi geojibby, Geocaching .com does not have a category for Canadian Benchmarks unfortunately. The Calgary Geocachers have a list of many of Alberta Brass Caps/Benchmarks/surveymarkers. www.calgarycachers.ca mwellman Quote Link to comment
+RCA777 Posted November 10, 2010 Share Posted November 10, 2010 ...you could always go to the cache page of a cache near you... and click on "All nearest WAYMARKS"... and then perhaps one of the nearby Waymarks will be a Benchmark with it's designation and location. e.g. You recently found "Moray Monster" Clicking on "Nearest Waymarks" displays a LOT of Canadian benchmarks. 500m from that cache is Benchmark "74M611 - Winnipeg MB". To research a Canadian benchmark, go to the NRCan site and navigate to : Natural Resources Canada > Earth Sciences Sector > Priorities > Canadian Spatial Reference System You can use the free user account to then do "Online Database" and then do a "CSRS Database Request" . You are looking for the "Station Unique Number Search" ID. Quote Link to comment
+RCA777 Posted November 10, 2010 Share Posted November 10, 2010 And for that benchmark... STN NO NAME EAG Latitude Longitude HDA O I M YRA ELEVATION VDA O Q M DATUM YRA SMC COND NTS 74M611 74-M-611 100 49 52 30 97 15 58 S S 237.446 100 1 P 1 CGVD28 1974 1 1 062H14 Quote Link to comment
+geojibby Posted November 11, 2010 Author Share Posted November 11, 2010 (edited) Thanks for the help on this one. I tried the Waymarking tip for caches that are local to my area and I did not yield any results. I have found 2 benchmarks/brass caps near my area and they both had "2450" stamped on them, as well as "geodetic survey of canada" - I uploaded this pic as part of a geocache log. Edit: I didn't get anywhere using CSRS database. Very puzzled about that. OK, I was able to do search based on location and that provided me with a bunch of results. My goal is to test the "accuracy" of some GPSrs so, which of the results is the best to find for averaging coordinates? Are all these stations and what not surveyed with the same accuracy? Edited November 11, 2010 by geojibby Quote Link to comment
+RCA777 Posted November 11, 2010 Share Posted November 11, 2010 ...OK... so if I go by your first cache placed (assuming that's "Close to home") and I look at Geodetic markers in your immediate area... I get this (and a whole bunch more) 24502 DUNBAR 100 49 2 24.8 102 40 9.4 Y 610.2 100 U X 2 CGVD28 1976 1 1 062E02 24503 SPY 100 49 1 26.5265 102 17 30.5489 100 Y A R 2001 585.9 100 Y X 6 CGVD28 1982 1 1 062E01 24505 MARTIN 100 49 2 19.4 102 4 51.2 Y 1 1 062E01 24506 GOERTZ 100 49 3 54.5 101 50 1.4 Y 1 1 062F04 The image you uploaded is of a triangulation station not a typical "marker". Its position has been determined by measuring distances and angles from other stations. I don't see record of them (unless they are the ones listed above -- but I don't believe they are). If you go onto the same webpage and do a "Radius Search" around your home co-ords you should hit a "Benchmark" that is listed and has record co-ords to play with. I'm looking more.... can you post (or message me) rough co-ords to play with if my "first cache you placed" guess is way off I'm enjoying this... the NRCAN site is better than I recall! Quote Link to comment
+geojibby Posted November 11, 2010 Author Share Posted November 11, 2010 Ok, I redid the radial search and I got one station within 10km of home. The station number is: 11S56C and generated this long report: SITE IDENTIFICATION Unique Number : 11S56C Name : 56C Established by : Geodetic Survey Division Province : SK Prov. Identifier : None NTS Map No : 062E01 STATION COORDINATES Method : Scaled Latitude : N49° 14' 06" Longitude : W102° 12' 54" Agency : Geodetic Survey Division - NRCan UTM : Zone = 13 Scale Factor = 1.0001 N = 5457313 m E = 702730 m VERTICAL DATA Vertical Datum : CGVD28 Elevation : 556.993 m Order : First Order Method : Differential Adjustment Line : VA13 Published Year : 1911 STATION MARKER INFORMATION AND LOCATION Marker Type : Permanent Agency Marker Inspected in : 1911 Status : Good Inspection Comments : None OXBOW C.P.R., CONCRETE ARCH CULVERT , 188.2 KM FROM KEMNAY, 3.2 KM NORTHWEST OF STATION, BETWEEN THIRD AND FOURTH POLES EAST OF MILE POST 117, TABLET IN WEST END OF NORTH FACE, 21 CM BELOW TOP. HISTORICAL COORDINATES NOTE: Coordinates listed below are no longer maintained by GSD and should be verified with your provincial agency before use. None PROJECTS IDENTIFIERS: 49102 VA13 So I just punch in these coordinates, go there and there will be something there matching this description? ...OK... so if I go by your first cache placed (assuming that's "Close to home") and I look at Geodetic markers in your immediate area... I get this (and a whole bunch more) 24502 DUNBAR 100 49 2 24.8 102 40 9.4 Y 610.2 100 U X 2 CGVD28 1976 1 1 062E02 24503 SPY 100 49 1 26.5265 102 17 30.5489 100 Y A R 2001 585.9 100 Y X 6 CGVD28 1982 1 1 062E01 24505 MARTIN 100 49 2 19.4 102 4 51.2 Y 1 1 062E01 24506 GOERTZ 100 49 3 54.5 101 50 1.4 Y 1 1 062F04 The image you uploaded is of a triangulation station not a typical "marker". Its position has been determined by measuring distances and angles from other stations. I don't see record of them (unless they are the ones listed above -- but I don't believe they are). If you go onto the same webpage and do a "Radius Search" around your home co-ords you should hit a "Benchmark" that is listed and has record co-ords to play with. I'm looking more.... can you post (or message me) rough co-ords to play with if my "first cache you placed" guess is way off I'm enjoying this... the NRCAN site is better than I recall! Quote Link to comment
+PDOP's Posted November 11, 2010 Share Posted November 11, 2010 You probably want to choose another one: Method : Scaled A lot of these are scaled off a map and so will be 10's of metres off. If you're wondering why a benchmark would be so inaccurate, many of these are used for gravity measurements only and have very accurate elelvations. Inspected in : 1911 HISTORICAL COORDINATES NOTE: Coordinates listed below are no longer maintained by GSD and should be verified with your provincial agency before use. If true that's quite old. Anybody here know if Saskatchewan has an online database open to the public? Quote Link to comment
+tec_64 Posted November 12, 2010 Share Posted November 12, 2010 Try and find ones that are "First Order" for the horizontal. As well, there are 1st order GPS references as well. For an example, see this one: http://www.Waymarking.com/waymarks/WMMN1_G...3014_Sudbury_ON Wayne tec_64 Sudbury, ON. Quote Link to comment
+stagunner Posted November 12, 2010 Share Posted November 12, 2010 (edited) You should get a free account at NRCAN see http://www.geod.nrcan.gc.ca/online_data_e.php this will then let you search for more databases,, the Canadian High precision Network has several control stations of very high order in several locations in each province These are set up to allow GPS users access to precise survey point locations to calibrate their receivers,, As mentioned above the survey control point may be listed as a First Order point but it's coordinates may not be updated in the data base,, do the research or if you want I can find a point close to you if you want,, send info to me,, Edited November 12, 2010 by stagunner Quote Link to comment
+tec_64 Posted November 12, 2010 Share Posted November 12, 2010 Ok, try this for a provincial database: http://www.isc.ca/Pages/default.aspx Select Survey Plans from the tabs. You'll need to sign up for an "account". I didn't go past that. Wayne tec_64 Sudbury, ON. Quote Link to comment
+geojibby Posted November 15, 2010 Author Share Posted November 15, 2010 What's the difference in scaled or differential? Quote Link to comment
+PDOP's Posted November 16, 2010 Share Posted November 16, 2010 What's the difference in scaled or differential? Scaled means measured off a paper map. A lot of these are for the Canadian Gravity Standardization Net (CGSN) Differential is an accurate type of GPS surveying. See How to do a GPS survey to centimetre accuracy. Quote Link to comment
+geojibby Posted November 17, 2010 Author Share Posted November 17, 2010 So is differential preferred for benchmarking (that is, averaging a waypoint with a GPSr)? What's the difference in scaled or differential? Scaled means measured off a paper map. A lot of these are for the Canadian Gravity Standardization Net (CGSN) Differential is an accurate type of GPS surveying. See How to do a GPS survey to centimetre accuracy. Quote Link to comment
+PDOP's Posted November 17, 2010 Share Posted November 17, 2010 So is differential preferred for benchmarking (that is, averaging a waypoint with a GPSr)? Definitely. Quote Link to comment
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