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Questions tagged [geodetic]

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Transform from Bessel to WGS84

Is there direct transform possible from Bessel ellipsoid to WGS84? This coordinate pair corresponds to same point on Earth but importing them for example in QGIS results in 100m shift. Bessel (EPSG:...
Oto's user avatar
  • 1
0 votes
1 answer
35 views

Can GeoTools parse GML geodetic shapes?

I am trying to parse different GML definitions, according to the geodetic shapes defined in RFC-5491. Points and polygons are parsed OK with GeoTools parser: Configuration configuration = new ...
llmarti's user avatar
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0 answers
47 views

Detecting intersection of two WGS84 lines

How do you detect intersection of two WGS84 lines given the information below known. RedLine: latStart0, lonStart0, latEnd0, lonEnd0 BlueLine: latStart1, lonStart1, latEnd1, lonEnd1
Kitiara's user avatar
  • 101
1 vote
0 answers
174 views

Find a new geo coord moving a given distance and angle from a previous point

I'm not interested in plotting or converting to Cartesian, just following a traverse from one lat/lon to a new one. Given two ends of a runway in decimal latitude & longitude Calculate the angle ...
Brian L Cartwright's user avatar
4 votes
2 answers
1k views

Convert geodetic to topocentric coordinates in pyproj

I'm trying to convert between topocentric coordinates and geographic coordinates with pyproj. First, I made a topocentric CRS using the proj4 string from the example here. Then, I made a geodetic CRS ...
tango-taylor's user avatar
1 vote
0 answers
274 views

Ordinary kriging in QGIS with geodetic coordinates

I am using QGIS 3.16.9 Hannover. I want to create a surface (with kriging) from a list of points whose SRC is WGS84, so I am working with geodetic coordinates. They are in decimal degrees covering a ...
Maria Eugenia Gomez's user avatar
1 vote
1 answer
276 views

Molodensky Transform with PROJ

I'm trying to transform some geodetic coordinates from the Ellipsoid (Hayford) to WGS84. I downloaded QGIS and I'm trying to use PROJ, with the OSGeo4W shell. I'm trying first to run the example ...
Karl's user avatar
  • 111
1 vote
0 answers
40 views

Geodetically correct point spacing accounting for change in elevation

I am trying to create a grid of points at a specific spacing (30ft) for setting up a new orchard on fairly steep terrain. I have tried using "create fishnet" in ArcGIS pro. This is giving ...
SSweet's user avatar
  • 19
5 votes
2 answers
447 views

Plotting line on QGIS

I have QGIS loaded on a couple of (Linux) computers, but by and large have used it as little more than an improved "Google Earth" with attempts at getting live data updates etc.; I've not ...
Mark Morgan Lloyd's user avatar
2 votes
2 answers
2k views

Creating a circle in actual meters

How can I create a circle (or "buffer") around a point anywhere on the globe in modern Open Layers with a radius specified in actual meters? "Actual" meters meaning that a geodetic ...
bugmenot123's user avatar
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1 answer
180 views

How does Google Earth calculate the inverse geodesic problem, in particular the forward azimuth?

Comparing the result of Vincenti’s formulae as implemented in https://geographiclib.sourceforge.io/cgi-bin/GeodSolve with the output of Google Earth Pro I find a striking difference in results for ...
Ralph Beckmann's user avatar
2 votes
1 answer
875 views

Converting to geodetic latitude, longitude

I’m writing a program to determine a vector between two points on earth by taking the difference of the ECEF vectors for each point. I’m using this algorithm: https://www.mathworks.com/help/aeroblks/...
PerplexedDimension's user avatar
3 votes
3 answers
4k views

What is the height reference point when using Longitude, Latitude , Height coordinates?

I'm using a library to convert LLH(WGS84) to ECEF coordinates. Does height (for corresponding longitude and latitude) denote height above/below the designated earth radius (I'm using 6378137.0m) or ...
Geordie's user avatar
  • 173
5 votes
1 answer
761 views

With respect to what "normal" is geodetic latitude defined for the WGS84 elliptical model of the Earth?

There are some features of geodetic latitude specifically with respect the WGS84 that I do not quite understand. In short: With respect to what "normal" is geodetic latitude defined for the WGS84 ...
Robby McKilliam's user avatar
-1 votes
1 answer
52 views

Why there is a different relative to Geodetic Azimuth from Arc Map from the original datums and transformations?

We where conducting a displacement for some BM (Old vs New values), we made calculations on different platforms for the North, East, Elevations. We used the NGS NCAT, Inverse 3D, TBC and manual ...
Leo's user avatar
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0 votes
0 answers
385 views

Converting geocentric coordinates to geodetic coordinates?

I would like to start by saying that I am very new to this. I have 160 different points which all have similar layout as below: at point | X= 153346.357 | Y=354912.111 | Z=0 | Doing some research I ...
user10764803's user avatar
2 votes
0 answers
51 views

How do you decide a new datum?

How do you decide datum size (axies a & b) and datum position relative to WGS84 (dx,dy,dz,rx,ry,rz) for a country if you were to create a new datum best fit for the country? Example, is datum ...
Kyaw Naing Win's user avatar
1 vote
1 answer
607 views

Can we say ECEF datum like in Geodetic datum?

Commonly we use geodetic datum to describe the geoid, a distorted ellipsoid model of the Earth, but is it correct to say Earth-Centered Earth-Fixed (ECEF) datum? Because we are applying ECEF to a ...
Minimalist's user avatar
7 votes
1 answer
477 views

Implementing Helmert transforms between reference frames / coordinate systems?

I'm trying to implement a 14-parameter Helmert transform to convert between terrestrial reference frames, and having difficulties with it. I have successfully followed the example in ITRF to GDA94 ...
ChrisV's user avatar
  • 93
0 votes
1 answer
1k views

ECEF to relative displacement in meters

I have GPS NMEA (National Marine Electronics Association) data that I collected being stationary and I can see the displacement of 4 meters just by looking at GPX data uploaded to google maps. I am ...
Mour_Ka's user avatar
  • 103
11 votes
3 answers
698 views

Latitude above and below the surface of the Earth

I know that Geodetic Latitude is measured with respect to the normal at a point on the surface of the reference ellipsoid. But what about points above and below the surface? Do they follow a ...
posfan12's user avatar
  • 245
0 votes
0 answers
88 views

Latitude of landmarks

I am new to mapping. Is there an online resource that lists both the geocentric and geodetic latitudes of various world landmarks?
posfan12's user avatar
  • 245
0 votes
1 answer
1k views

Oracle equivalent to postgis EPSG 4326 "geometry" type

We have polygons stored in Oracle SRID 8307 (geodetic datatype), but need to perform various operations on this layer in a 2d cartesian/non-geodetic system based on the geographic coordinates. I.e. ...
Lars's user avatar
  • 3
1 vote
1 answer
426 views

Converting Korea 2000 coordinate system to WGS84?

I have coordinates in Korea 2000 EPSG:5181 projected coordinate system. Is there a way to make a formulation in excel to convert these coordinates to lat long (WGS84)?
Aqi's user avatar
  • 21
2 votes
1 answer
1k views

Can't get RTKLIB to use an external geoid

I want to write the results of processing a Rinex file using geodetic heights, and an external geoid from Spain's geographic institute IGN. I have downloaded the geoid files from their FTP in text ...
Anthony's user avatar
  • 21
3 votes
3 answers
1k views

Transformations OSTN02 to OSTN15

I have a collection of points in a .CSV which are currently in OSGB36 and have been through the OSTN02 transformation. I would like to put them through the OSTN15 transformation in bulk, using the ...
JG_RS_GIS's user avatar
  • 113
3 votes
0 answers
463 views

How to determine the lat long of a point in the atmosphere which is 250 km altitude?

Regarding determination of coordinates of Ionospheric Pierce Point (IPP) S is the position of a geostationary satellite. E is the elevation angle. The radio signal ...
omkar gurav's user avatar
1 vote
1 answer
321 views

What is the "Long-Wavelength Error" reported for SRTM data?

Assessments of SRTM topographic products (like Rodríguez et al 2005 and 2006) report that height errors showed coherent long-wavelength signatures and describe long-Wavelength error characteristics. ...
Jecogeo's user avatar
  • 291
0 votes
0 answers
180 views

Inconsistent coordinates of centroid were found using the given value of radius of curvature in the prime vertical and in the meridian

I am currently writing a function on geodetic datum transformation in Hong Kong by referring to the Explanatory Notes on Geodetic Datums in Hong Kong by the Survey & Mapping Office of the Lands ...
pe-perry's user avatar
  • 163
0 votes
0 answers
154 views

Constructing geodetic lines

I am trying to construct a geodetic line between destinations. I have followed two guides without luck. This are the steps I've done: I created a polyline shapefile and named it "Distance" I went to ...
Kangaroo's user avatar
  • 145
1 vote
1 answer
384 views

Getting geodetic area from rgeos::gArea? [closed]

I need to get an area of different polygons at continental scale (like third of Africa etc.). Usual functions like rgeos::gArea work only in the projection units. Is there any function which works ...
Tomas's user avatar
  • 1,252