# Questions tagged [geodetic]

The tag has no usage guidance.

31 questions
Filter by
Sorted by
Tagged with
42 views

### 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:...
• 1
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 ...
• 11
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
• 101
1 vote
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 ...
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 ...
1 vote
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 ...
1 vote
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 ...
• 111
1 vote
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 ...
• 19
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 ...
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 ...
• 10.9k
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 ...
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/...
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 ...
• 173
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 ...
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 ...
• 1
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 ...
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 ...
1 vote
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 ...
• 125
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 ...
• 93
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 ...
• 103
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 ...
• 245
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?
• 245
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. ...
• 3
1 vote
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)?
• 21
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 ...
• 21
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 ...
• 113
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 ...
1 vote
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. ...
• 291
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 ...
• 163
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 ...
• 145
1 vote