Questions tagged [datum]

The information connecting numerical coordinates to actual locations on the earth.

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2answers
85 views

Convert Vertical Datum of GDAL file

I have 2 DTM datasets, the first has a vertical datum of WGS84, while the second has an orthometric vertical datum (maybe EGM96). gdalinfo seems to only provide the horizontal datum info: Size is ...
2
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1answer
39 views

Identifying vertical datum of raster

I have a DEM that purports to use the Canadian Geodetic Vertical Datumn 1928 (CGVD28) where heights are normal-orthometric. However, when I run gdalinfo dem.tif from the command line the output for ...
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0answers
33 views

How is Trimble Pathfinder Office transforming positions?

I am struggling to understand how Trimble’s Pathfinder Office transforms and exports GNSS data and I’m hoping someone here can explain. I've seen posts like this and this, and documents like this, but ...
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1answer
29 views

Raster does not match the target extent and shape of another raster ArcGIS

I have future climate data in .nc format. I transferred them into multiband rasters so I can separate them using another tool and make some calculations. I faced one issue in one variable where it had ...
2
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1answer
47 views

Finding the correct aspect ratio from image

I'm trying to put an image over my map. I know the correct bounding box of it, but when I load it, I see it doesn't fit correctly in the map. Just for curiosity, I cut a piece of map of same region ...
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0answers
33 views

Ellipsoidal to Orthometric Height Conversion

I have two DSM, one generated using lidar data in NAVD88 and the other I produced using stereo images in WGS84 G1150. I am trying to covert G1150 to NAVD88. I have tried a few conversion tools, ...
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0answers
25 views

How to perform a helmert transformation (localization, site calibration, etc)?

I may be going at this problem the complete incorrect way, I just need some guidance is all. I need to perform a helmert transformation on lat/long to convert to a users local grid system that they ...
2
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1answer
65 views

Custom datum transformation in bash or Python

I need to transform a shapefile from Deir ez Zor / Levant Stereographic (EPSG:22780) to UTM 36N using 7-parameters Helmet transformation on Ubuntu bash script or Python script. In ArcGIS, I can ...
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1answer
27 views

vDatum returns error at Linux command line - fails to accept parameters with GUI

I am trying convert a GeoTiff using VDatum at the Linux command line. My data reference the Washington State Plane South CRS with z values referencing EGM96. I would like to convert these z values to ...
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0answers
32 views

Identifying undefined vertical datum

I was given two DEM files covering the same area of Northern California (lets call them File_A and File_B). They're derived from LiDAR that was flown separately in the last 10 years. My goal ...
2
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1answer
109 views

PostGIS ST_Transform seems to treat the vertical datum but not the equivalent pyproj Transformer, even so they both rely on Proj

I've narrowed down a problem I met when processing some points having altitude values to the following: It seems that PostGIS and pyproj do not treat the vertical datum in the same way but both are ...
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0answers
38 views

Datum transformation with velocity corrections

I have a coordinates with velocity values of some points in ITRF2014 at 2010.0 epoch and I want to convert these coordinates to ITRF96 1998.0 epoch. I apply the velocity corrections to my coordinates ...
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0answers
47 views

Special relationship between EPSG:4326 and EPSG:4369

This is a follow-up question to a previous one (Projection between EPSG:4326 and EPSG:4269 using pyproj does nothing). When using pyproj (python 3.8.8 and pyproj 3.0.1 on windows) to project a point ...
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0answers
174 views

Projection between EPSG:4326 and EPSG:4269 using pyproj does nothing [duplicate]

According to this quite thorough answer : Is re-projection needed from SRID 4326 (WGS 84) to SRID 4269 (NAD 83)? the crs EPSG:4326 and EPSG:4269 are slightly different, due to a difference in one of ...
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0answers
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Datum transformation not working properly [closed]

I want to create a map with 20 coordinates (UTM), that I have loaded as a CSV-file into QGIS 3.12. The area is located in UTM zone 32 U (northwest of Munich). As a background I want to use an 80 cm ...
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0answers
25 views

Encoding user-defined datum and projection in GeoTIFF for a non-Earth image?

I'm writing code to export maps (photos, elevation models, other measurement data) of fictional celestial bodies from a videogame into GeoTIFF with correct georeferencing, so that they could be ...
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1answer
335 views

Transformation datum from WGS84 to BTM (Bangladesh Transverse Mercator)

I'm changing raster layers in ArcMap from WGS84 to BTM (Bangladesh Transverse Mercator). I first set my data frame to be in BTM [BTM Projection: Transverse_Mercator False_Easting: 500000.0 ...
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0answers
53 views

Visualizing resource dependencies and relationships underlying EPSG CRS

I'll go straight to the point; I remember long ago that I was quite shocked the first time I discovered that EPSG:4326 was kind of an "umbrella" definition on top of many others, which often ...
0
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1answer
53 views

NAD27 data distributed in NAD83 by Canadian government

Natural Resources Canada (NRCAN) produced 1:50000 topo maps for all of Canada according to the Natural Topographic System grid configuration. The maps are now considered a legacy product, but GeoTIFFs ...
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1answer
83 views

EPSG for TanDEM-X Ellipsoid

I have TanDEM-x data and according to the documentation: "The elevation values represent the ellipsoidal heights relative to the WGS84 ellipsoid in the WGS84-G1150 datum." I would like to ...
5
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1answer
297 views

Understanding EPSG in WKT

I notice several EPSG codes in one WKT. At the first glance it almost is non-intuitive to see so many EPSG codes linked to a single EPSG. Can someone explain each line of the following WKTs for EPSG:...
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2answers
38 views

Drawing two points in two datums with same coordinate value

Today I was trying to use ArcMap to find out what is the distance between two locations with same coordinate values in NAD27 and NAD83, but the points I drew appeared to be at the exact same location. ...
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2answers
44 views

Failure to project shapefile to Mass State Plane NAD83 (meters) SRS with ArcMap

I am working with a shapefile that I have not been able to project to the Mass State Plane NAD83 meters (i.e., EPSG:26986) SRS using ArcMap's "Project" tool. The "Project" tool ...
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0answers
75 views

Why do I continue to get a datum conflict message even though layers match?

I have a document with multiple raster layers and a set of buffer zones for which I am trying to use the zonal statistics tool to summarize some of the raster information within the buffers. Most of ...
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0answers
97 views

Using NTV2 transformations in MapInfo

I am investigating the use of MapInfo to apply transformations between GDA94 and GDA2020. I am using MapInfo Pro 2019.1 so the NTv2.xml file has 10 entries relevant to Australia. They come in pair ...
0
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1answer
77 views

Setting a custom projection in ArcGIS, from data provided by the Government of Mauritius?

I am trying to save a custom projection in ArcGIS. It is a local projection used by the Land Unit from the Government of Mauritius. Below are the information provided by the government: My question ...
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1answer
423 views

get "Cannot find coordinate operations" in GDAL 3; works in GDAL 2

I get the following error when trying to use GDAL 3.1.2 for computing the LLA from my custom gnomonic projections. Am I setting it up wrong? Missing some information/files? Would it be a misconfigured ...
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0answers
87 views

How to convert elevation data from Google Elevation API to NAVD 88?

I want to convert the elevation data obtained from Google elevation API to NAVD 88. I understand that Google uses WGS84 with EGM96 Geoid. Do you know what I should do to convert the elevation data? ...
3
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1answer
71 views

Datum transformation in QGIS Server 3.10

I have a QGIS project that uses data stored in Web Mercator (epsg:3857) spatial reference system. The project itself has epsg:5514. To have a better precision I use one of datum transformations that ...
7
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1answer
196 views

What is MHHW Mean Highest High Water, in terms of datums/coordinate systems?

I'm modeling sea level rise, which entails adding the projected sea level rise for a specific decade to the current MHHW height (I think. I am new to this.) My question is very general--what is MHHW ...
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0answers
296 views

Conversion of EGM96 to NAVD88

I am new to ArcGIS and geoids/ellipsoids, and I want to convert a dataset in EGM96 (the USGS SRTM DEMs) to NAVD88. I have the SRTM dataset from NASA downloaded and open in ArcGIS as .hgt files. I ...
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0answers
179 views

Datum Transformation from WGS84 UTM Zone 35N to ED50UTM Zone 35N with a grid shift file (.gsb file)

I would like to transform WGS84 UTM Zone 35N coordinates to ED50UTM Zone 35N coordinates with a grid shift file (.gsb file I have) in python using pyproj. I tried below code but it gives failed to ...
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0answers
83 views

Geographic Transformations in QGIS 3.12

I have a problem with the way that QGIS handles transformation parameters between coordinate systems based on the Datum NAD27 and those based on the Datum WGS84. In version 3.12.1 I have found that ...
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0answers
79 views

Aligning different vector features and vector features with rasters

I am fairly new to GIS and I encountered this problem concerning projections. Maps don't align despite having the same projections (according to the Properties - XY Coordinates). I already tried with ...
-1
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1answer
26 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 ...
2
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1answer
235 views

Difference between datum transformations in QGIS 3.4 and ArcMap 10.7

Could someone briefly explain the difference between how datum transformations are handled by QGIS versus ArcMap? For example, I am under the impression that in QGIS you can simply select a ...
3
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1answer
447 views

Path to add NTv2 transformation to QGIS

Every time I start a new QGIS project, I have to add the BETA2007.gsb NTv2 Transformation. I would like to modify my QGIS settings in a way, that the NTv2 is automatically added to the project. When ...
2
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1answer
183 views

What is the meaning of "SI-D-48-Gauss_Kruger" projection used in an ESRI WKT string?

Recently I encountered the following WKT CRS definition from an ArcMap project: PROJCS["SI-D-48-Gauss_Kruger",GEOGCS["GCS_Bessel_1841",DATUM["D_Bessel_1841",SPHEROID["Bessel_1841",6377397.155,299....
2
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1answer
232 views

Reproject in QGIS doesn't work the way like in ArcGIS [closed]

Sometimes I get polygon data that digitizes buildings, but they are slightly displaced like in the following example However, when I use the ArcGIS Tool "Project" to project the layer from a ...
2
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1answer
297 views

Which ArcGIS 10.7 transformation to convert WGS84 data to Washington State Plane North?

A bulk of my GIS datasets reference Washington State Plane North FIPS 4601 (US Feet). Often I get data in WGS84 that I need to transform to FIPS 4601. Ten years or so I worked though many of the ...
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0answers
48 views

Identifying of Vertical Datum from Metadata

I have been working with the DEM of South Carolina and I am not able to see from the metadata what is the vertical of the DEM. How do I identify the vertical datum from the attached screenshot of ...
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0answers
188 views

How to convert ITRF to ITRF

ITRF 96 1998.0 epoch X Y Z Vx(m/y) Vy(m/y) Vz(m/y) 4059623.25 2764405.93 4056720.43 -0.0079 -0.0007 0.0132 Transformation parameters from ITRF1996 to ...
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0answers
103 views

Problems importing raster to GRASS from QGIS (error: Datum ETRS89)

When I try to import raster from QGIS to GRASS with r.in.gdal.qgis an error of projection appears. Raster is in EPSG::25831 - ETRS897UTM zone 31N and mapset is supposed to be defined with the same. ...
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0answers
84 views

Shapefile appears correct on QGIS, but wrong on Google Earth

I've created a shapefile on QGIS, drawing over a raster that I've just georeferenced. The raster is a map with UTM lines drawn every 50 meters, so it was easy to georeference. Moving the mouse over it ...
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2answers
479 views

Adequate proj4string for ETRS89

I am currently working with spatial data in R using sp When I used WGS84-referenced coordinates, I used to specify it by setting the proj4string to: +proj=utm +zone=18 +datum=WGS84 +units=m +no_defs +...
2
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0answers
52 views

How to run OSGeo4W shell for molodensky transform?

I'm a beginner with Proj, so I just downloaded proj, and I'm using the OSGeo4W Shell and when I try to run the example proj=molodensky a=6378160 rf=298.25 da=-23 df=-8.120449e-8 dx=-134 dy=-48 dz=...
0
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2answers
139 views

What are the standard values of the GPSMAPDATUM attribute in the exif standard?

I'm working on an application to read the exif georeferenced metadata of some photos. I would like to know all the possible values of the attribute GPSMapDAtum. Do you know where to find a list with ...
1
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2answers
242 views

Transform datum CSV->CSV using ogr2ogr

First I have a set of points in UTM 48S / WGS84 (EPSG 32748) as test.csv: X,Y,Z 9231824.04,787648.04,711.1442 Second I defined a test.vrt for ogr2ogr to read the data as follows <...
3
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1answer
59 views

Why are there differences in output position between the ArcGIS versus NCAT transformation [NAD83 to NAD83 HARN]?

My question is specifically referencing the file-based grid transformation methods that are now available in ArcGIS. I thought this grid-file method was exactly the same method that NGS's NCAT used ...
2
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0answers
43 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 ...

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