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

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3
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1answer
41 views

What's the best way to handle a 'Site Datum' in QGIS?

So I have a client with a site datum, which is to say they have an arbitrary coordinate reference system with coordinates between -1000 and 1000 in X and Y. I have a list of ~20 coordinates that maps ...
0
votes
2answers
14 views

Problem transforming data from GCS Krasovsky to GCS WGS84

I am having trouble transforming data from GCS_Krasovsky_1940 to GCS_WGS_1984 in ArcGIS 10.4.1. I'm using the Project tool, but the geographic transformation parameter is left empty and I would expect ...
2
votes
1answer
52 views

Defining Datum in QGIS?

I got two shapefile of the same coordinate reference system (CGRS93_LTM), one in QGIS and the other in ArcMap. However they got different prj. files QGIS file: PROJCS["Transverse_Mercator", GEOGCS["...
3
votes
1answer
28 views

Problem with MGI CRS on the Balkan

I have problem with CRS Bosnia and Herzegovina? MGI 1901 / Balkans zone 6 EPSG:3908 MGI 31276 / Balkans zone 6 EPSG:31276 Which of these two is OK? When I open google sattelite image with ...
0
votes
0answers
20 views

How to create a new datum transformation within the ArcGIS REST API?

I'm trying to get a new (EPSG) datum transformation parameter added to the ArcGIS REST API so that I can then get a WKID code for use in ArcGIS Online applications. Does anyone know how to get a new ...
0
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0answers
39 views

Algorithm for converting from projected coordinate system to geographic one using Helmert transformation

I have a data in projected coordinates system and I need to convert them to WGS84. I know the parameters of position vector transformation and I know the projection details of my projected coordinate ...
8
votes
1answer
163 views

What is my coordinate system preserving?

I'm trying to get a better grasp of coordinate systems, datums, projections etc. I understand that certain systems preserve different things; distance, shape, angles, area. I'm wondering how you can ...
1
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0answers
34 views

6 degree of freedom helmert transformation

I'm looking to do datum conversions for points with six degrees of freedom, that is, they are described by a heading, pitch, and roll in addition to their position information. I know how to convert ...
0
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0answers
47 views

gdaltransform returns ERROR 1: failed to load datum shift file

I'm trying to do a NAVD88 to WGS84 (G1674) conversion using gdal. I've installed gdal (on centos7) using sudo yum install gdal proj-epsg proj-nad and am trying to perform the conversion via: ...
3
votes
1answer
43 views

VDatum helmert transform parameters

I'm trying to use NOAA's VDatum to verify the NAVD88 -> WGS84 datum conversion in a c++ datum conversion library that I've written. The answers didn't agree, so I attempted to check a simple ITRF2008 ...
1
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0answers
25 views

QGIS x ArcGIS - Geoprocessing Vectors in Geographic Coordinate Systems [closed]

Is there a possibility of in future versions of QGIS, the software be able to geoprocess vectors (clip, buffer, intersection, etc.) in Geographic Coordinate System, and not only in UTM? In ArcGIS, ...
1
vote
2answers
82 views

Datum shift issue between OSGB1936 and WGS84

I have to work between OSGB1936 and WGS84 and BOTH of these data sets started out life as OSBG1936 BounaryLine data. I thought I was just at the end of a full revision of my master mapping until I ...
1
vote
2answers
154 views

Is WGS 84 datum, coordinate reference system, or both?

The background to this question is in Understanding difference between Coordinate System and Projection? There @mdsumner commented: WGS84 is not a cs, it's a datum. On a couple of places online ...
3
votes
1answer
57 views

Why does QGIS do an unintended datum shift to WGS84 in the map canvas

I'm a new QGIS user running 2.12 Lyon. I've encountered an issue with map canvas units and an unexpected and transparent datum transformation to WGS84. I need help figuring out if I've missed ...
4
votes
1answer
89 views

Datum and transformation error using ST_Transform in PostGIS, going from NAD83 to NAD27

I created a function in PostgreSQL to transform input coordinates using UTM Zone 12/13, with Datums NAD83 or NAD27, to the WYLAM projection. I had to manually create the entry for the proj4text ...
4
votes
1answer
96 views

WRF Spherical Earth to WGS 84

Weather Research Forcasting Model assumes a spherical earth model with a radius of 6370km. I'm looking to display the data onto the WGS-84 Ellipsoid model as that is the model my system uses for its ...
3
votes
2answers
83 views

How to re-project a shapefile to be compatible with another shapefile or raster?

I have a polygon shapefile and a raster. The shapefile and raster have different coordinate systems. Coordinate System for the shapefile: NAD_1983_UTM_Zone_19N WKID: 26919 Authority: EPSG ...
6
votes
3answers
144 views

Vertical datum query for coastal modeling

This may be very specific. I have a USGS derived DEM with a vertical datum of EGM96 from NASA satellite data. My Bathymetry uses a lowest astronomical tide datum. Has anybody come across this or ...
3
votes
1answer
176 views

Difference between datum and ellipsoid for geodetic coordinates?

Looking at the Wikipedia page for the North American Datum, it seems to imply that the datum is completely defined by the ellipsoid, which defines the major/semi-major axes, flattening, etc. For ...
11
votes
1answer
692 views

why does the North American Datum not actually include north america in it's boundary?

http://spatialreference.org/ref/epsg/4269/ That link shows the area that the North American Datum 1983 covers and one thing I note is that it doesn't cover North America. It covers all of Asia and ...
0
votes
0answers
27 views

Valid Range of Geoidal Separation in GNS and GGA sentences

I haven't seen any information about valid ranges of geoidal separation in GGA and GNS sentences. I am using Nema Studio Simulator to simulate GPS receiver. In there Geoidal Separation can be set to ...
2
votes
1answer
297 views

Relation between Geoidal separation and antenna altitude in GGA sentence?

I have searched about definitions and relations about geoidal separation and antenna altitude reported in GGA sentence. The more I read the more I am confused.So in a simple manner can anyone explain ...
3
votes
0answers
52 views

Do locations “move” when shifting datum?

I hope that this is the right Stack Exchange for this question. I may be oversimplifying this, but I'm looking for verification in my understanding of the following: If I have a spatial dataset in 2 ...
1
vote
0answers
65 views

Strategies and methods that Datums and Coordinate Systems use to account for movement of the earth's surface

Are there datums and coordinate systems that address the issue of shifting coordinates through time? If so, what are some of the strategies and methods that the datums and coordinate systems use to ...
4
votes
2answers
129 views

Are Australian Height Datum and GDA94 applicable to Christmas, Lord Howe, and Norfolk islands?

I've been asked to recommend a mapping coordinate reference frame for use for Australian mapping, which I've said AHD for the vertical component and GDA94 for the the horizontal component. However, I'...
3
votes
1answer
49 views

What does it mean for two datums to be navigationally equivalent?

I read from NOAA that NAD83 and WGS84 are "navigationally equivalent" NOAA uses the North American Datum of 1983 (NAD 83) for all of its charts. This datum is navigationally equivalent to the ...
0
votes
1answer
37 views

How to set datum in GPS connection setup window in ArcFM Viewer for ArcGIS Engine Application

I have a custom application based on ArcFM Viewer for ArcGIS Engine. I want to use an external GPS receiver with that application and the setup window does not let me choose a different geographic ...
10
votes
3answers
1k views

What is the meaning of “Elevation above the surface of the ellipsoid”?

I'm using implementation of Vincenty's algorithms, and I have their class called "position" that requires lat, lon, and elevation defined by: "Elevation above the surface of the ellipsoid". What is ...
1
vote
1answer
960 views

What is/are the coordinate systems used in South Africa?

What are the principal datums and projections used in South Africa including the names of geodetic datums and their projections?
0
votes
1answer
205 views

Difference between WGS_1984_UTM_33N and GCS_WGS_84

What is the difference between: a map that has a projected coordinate system of WGS_1984_UTM_33N, a geographic coordinate system of GCS_WGS_1984, and a datum of D_WGS_1984 a map that has no ...
1
vote
1answer
95 views

Geosoft Oasis Montaj Local Datum Transform - What is the purpose of this parameter?

When defining a coordinate system in Oasis Montaj one of the parameters is "Local Datum Transform". Is this the coordinate transformation definition to convert the defined coordinate system of a data ...
1
vote
0answers
43 views

Geographic coordinate system and datum [duplicate]

I am bit confused about datums used to define a localised coordinate system for a specific area. Definitions say that, datum defines how a certain well-established point (i.e., reference point) on ...
0
votes
1answer
89 views

ArcGIS 10.2.2 Does “Batch Project” work for different input datum?

I have two vector data sets - one is in NAD27 and the other is in WGS84. Normally I reproject one at a time. But can I just use 'batch project' to reproject both of them to NAD83 at once? I was not ...
4
votes
1answer
572 views

Canadian Geodetic Vertical Datum of 2013 (CGVD2013)

"Natural Resources Canada (NRCan) has released the Canadian Geodetic Vertical Datum of 2013 (CGVD2013), which is now the new reference standard for heights across Canada. This new height reference ...
3
votes
2answers
300 views

methods for converting coordinate datum and format in python?

Related to an earlier Q&A of Missing grid shift files for cs2cs.exe? ... what are the various methods to convert coordinate datum and format in python? (Windows Vista, python 3.4) For example, ...
1
vote
1answer
313 views

Transform coordinates in MapInfo with GSB data

Does anybody know if MapInfo (or MapBasic) is capable to do coordinate transformation using the NTv2 (National Transformation version 2) method? Currently Switzerland changes their national ...
3
votes
1answer
244 views

Reprojecting between NAD27 and WGS 84 part III

I am trying to perform a reprojection for data with datum Nad27 to WGS84 datum. According to AndreJ in some previous questions in Stackexchange (CRS reprojection for instance) QGIS uses internally by ...
1
vote
1answer
333 views

Project from Datum Nad27 to WGS84

This should be simple: have a shapefile in UTM z16 DatumNad27 and want to transform it to Datum WGS84 latlon I am using Qgis 2.6 Sorry I am going to clarify, with the steps taken: 1- XY data of a ...
2
votes
2answers
2k views

ArcGIS Desktop:Transformations: Geographic vs Projected?

Arc10. I have two data sets (both CSV files w/ lat and long columns) and I am working on standardizing them to the same projection. File1: NAD27; File2: NAD27, WGS84, and NAD83. I would like all of ...
2
votes
1answer
232 views

Coordinate display in Terrasync

I'm using Terrasync on a Trimble GeoXH 6000 - set for WGS 84 and UTM. It acquires satellites fine, but instead of displaying my current location in UTMS, the skyplot screen shows "12RVU" and then a ...
2
votes
2answers
5k views

Transforming coordinates between wgs84 and UTM ED50 31N, what am I missing?

My problem is I must tranform a point cloud from wgs84 (geographic) to UTM (projected) ED50 for zone 31North. Easy, isn't it? Well, first surprise is I have several free webs who offer me this ...
0
votes
1answer
58 views

Converting datum?

I need to measure the distance (with the ruler) of points from two different layers. However, one layer is NAD83 and the other is NAD27. I also have a standard ESRI basemap downloaded. The issue I ...
2
votes
3answers
95 views

Change projection didn't change position in a vector shape in qgis

I got a shape of points and when i save it with another datum and open it again, it stays in the same position. I was hoping for a slight change in position when save from epsg:5361 to epsg:32719.
7
votes
2answers
352 views

Geo-referencing an old map

I'm trying to georeference this part of an old map of Indochina. . The full extent gives more information: . To do so, I used QGIS and tried to infere the datum, I tried "Unknown datum based on ...
2
votes
1answer
93 views

Figuring out what coordinates supposedly using 'NAD31 projection' refer to

I'm working with a GeoJSON file that contains sets of coordinates associated with street corners in the city of Montreal, Canada. The spec sheet of the API delivering those GeoJSON specifies that the ...
0
votes
1answer
630 views

ArcGIS Conversion Error While Converting ED50 Datum to WGS84 Datum

With ArcGIS for Desktop, I tried a datum conversion of Transverse Mercator ED50 Datum to Transverse Mercator WGS84 Datum. Normally, the difference between two projections is approximately 180 meters ...
1
vote
1answer
248 views

Find AB_CSRS.gsb for NAD_1983_TO_WGS_1984_8 Transformation

I am trying to change my WGS84 data to NAD83 for Alberta data. My research tells me that I need to use the NAD_1983_TO_WGS_1984_8 Datum Transformation which is in the AB_CSRS.gsb. I can not find this ...
0
votes
1answer
29 views

NAD conversion in Mexixo

I am looking for the file "Mexico.gsb" which used with ArcGIS when datum shifting from NAD27 to NAD83 in Mexico.
3
votes
1answer
260 views

Why not measure elevation from the center of the earth?

In trying to understand Geoid vs Ellipsoid height, I ran across this page. One of the claims is: Zero elevation as defined by Spain is not the same zero elevation defined by Canada Basically,...
2
votes
1answer
255 views

Origin of the OSGB36 datum origin

Interpreting 'GIS' in the geographical information science sense, I have a historical question about the 1936 OSGB datum following the 1936-62 retriangulation of Great Britain - hopefully not too off-...