NGS Coordinate Conversion and Transformation Tool (NCAT)

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Last Updated: Dec 05 2023

Convert/Transform from:

Horizontal

Horizontal+height

XYZ (Cartesian geocentric)

Select the type of horizontal coordinate:

Geodetic lat-long

SPC (State Plane)

UTM

USNG

Enter lat-lon in decimal degrees

Lat

Lon

or degrees-minutes-seconds

Lat

Lon

or drag map marker to a location of interest

Note the following for this alpha NCAT implementation:
Enables preliminary (alpha) State Plane Coordinate System of 2022 (SPCS2022). ITRF2020 is a proxy for the 2022 Terrestrial Reference Frames. Transformations to other frames are not available at this time. Auto Pick will return an SPCS2022 zone in most areas of the NSRS but may not give the desired zone because of zone layers. In those cases, select the desired zone from the pull-down list. NAD83 latitude and longitude can be used as input, but the output coordinates will differ horizontally from actual SPCS2022 by up to a few meters, depending on location (likewise for UTM and USNG). If NAD 83 ellipsoidal heights are used, the linear distortion and combined factor will differ from SPCS2022 values by a small amount, within ±0.3 parts per million (ppm). To reduce these differences, NAD83 epoch 2010.0 coordinates can first be transformed to ITRF2020 epoch 2020.0 using the Horizontal Time-Dependent Positioning (HTDP) tool

Input reference frame
(historically called 'horizontal datum')

Output reference frame
(historically called 'horizontal datum')

Don't see a reference frame in the list?Click here to learn more.

SPC zone

Click blue bar(s) to expand/collapse

Converted Coordinate

Reference Frame:

Lat-Lon-Height	SPC	UTM/USNG	XYZ

You may change the default UTM zone. The change is processed interactively once a lat-long is converted; DO NOT click the Submit button.

Customize Export

Mapping of NAD83 realizations to HARN and FBN

If you don't see your desired datum in the above list, it might be because the datum or datum realization is part of the NAD 83(HARN) or NAD 83(FBN) groups within CONUS. Please check the list below, and if your desired datum is on the HARN or FBN list, please use NAD 83(HARN) or NAD 83(FBN). If you do not see your datum on the list below, it is not supported by NCAT:

State	HARN	FBN
Alabama	NAD 83(1992)
Arizona	NAD 83(1992)
Arkansas	NAD 83(1997)
California	NAD 83(1992)	NAD 83(1998)
Colorado	NAD 83(1992)
Connecticut	NAD 83(1992)	NAD 83(1996)
Delaware	NAD 83(1991)
District of Columbia	NAD 83(1991)
Florida	NAD 83(1990)	NAD 83(1999)
Georgia	NAD 83(1994)

Convert/Transform from:

Horizontal

Horizontal+height

XYZ

Select the type of horizontal coordinate:

Geodetic lat-long

SPC

UTM

USNG

Input reference frame
(historically called 'horizontal datum')

Output reference frame
(historically called 'horizontal datum')

SPC zone

UTM zone

For faster processing, uncheck the coordinates you don't need in the output;"N/A" is filled in for an unchecked coordinate

SPC

UTM

USNG

XYZ

Upload Format: A comma-delimited text file with the following data elements; only '.txt', '.text', or '.csv' extensions are accepted

Column 1. ID

Column 2. Latitude

Column 3. Longitude

A sequence number or any ID

Dec. Deg or DMS

Dec. Deg(negative W) or DMS

Sample File

1,40.0,-80.0

2,N391326.71220,W0983231.74540

Upload data to be converted
Results are ready for download after a "Done" message appears

Choose

Status

Download NCAT: - Runs on any computer; - Needs java runtime. If you don't have one,you may download it here; - Download contains an application jar, a driver for the Command Line Interface (CLI), javadoc, and a readme file for CLI; - CLI is primarily intended for offline use. No internet connectivity is needed; - Alternatively, you may access the source code on github and customize it for your needs.

Nadcon5 grids. Learn more: - Needed for reference frame transformation; - Big endian .b binary format. What's a .b format?

Vertcon3 grids. Learn more: - Needed for geopotential datum transformation; - Little endian .b binary format. What's a .b format?

Tutorial

Part 1 of 2

Part 2 of 2

FAQs

What is the maximum file size that can be submitted to multipoint conversion?

NCAT allows up to 500K in file size
WGS84 is not an option in the conversion tool. If I have records from all over the world then which NAD 83 do I use in place of WGS84?

For now, you may use HTDP to transform WGS84 to NAD 83 first and use the transformed NAD 83 coordinates in NCAT. Future versions of NCAT may support WGS84. You may access HTDP from here
Is there a batch mode for the Web service or plans to implement one?

No, there is no batch mode for web service.
Are the results from NCAT and VDatum the same?

NCAT and VDatum share the same codebase and the results should be consistent between them. If you notice any discrepancies, please let us know.
I expect the NCAT output to have a combined scale factor, but it is missing. Is there something special that I have to do to get it to work?

An ellipsoid height is needed for combined scale factor computation. Please be sure to choose the horizontal+height option and enter a height.
How can I convert an elevation measurement for my home based on mean sea level datum from 1929 to reflect a more recent datum?

Please access NCAT from here
Once the page comes up, please select horizontal+height from the top row. Select orthometric from the third row. Enter your latitude, longitude and orthometric height. Towards the bottom of the screen you see an option to choose an input geopotential or vertical datum. Pick NGVD 29 from the dropdown and click submit. You should see transformed height under "Transformed Coordinate".
Will NCAT convert today's data to the modernized NSRS (NATRF2022, NAPGD2022, etc.), once fully implemented?

Yes, it will. Please keep an eye out for news or product update announcements on our website.
Is there a simple tutorial (or YouTube demo) on how to use the NGS Coordinate Conversion and Transformation Tool (NCAT)?

You can find tutorial videos at and click on the Tutorial & FAQ's tab.
Could I get the coordinate conversion tool to give me lat/lon in degrees-minutes-seconds instead of decimals of a degree?

The tool does generate results in both decimal degrees and degrees-minutes-seconds
Where can I access the source code for NCAT? The engine that powers NCAT, known as ncat-lib, is publicly available on github
Which browser is recommended for NCAT?

While NCAT works on all browsers, legacy versions of IE have known issues. NGS recommends Chrome for the best user experience.
Does NCAT convert between ellipsoid and orthometric heights?

The current version of NCAT does not support conversions between ellipsoid and orthometric height, but future versions will. For the interim, to compute an NAVD 88 orthometric height from an NAD 83 (2011) ellipsoid height please use the Geoid tool
Is the web-based NCAT tool a replacement for Corpscon 6?

No. CORPSCON is an official U.S. Army Corps of Engineers product, not an NGS product. Though CORPSCON offered integrated NGS products long before NCAT it has always been under the control of USACE. Although NGS is not aware of any issues with CORPSCON integrating NGS products and services, the only official tools NGS endorses for use in the NSRS are those directly under NGS control, such as NCAT.
It appears that the NAD 27 to NAD 83(1986) transformation changed when comparing NADCON 4 (or NADCON 2.1 which I believe was used in Corpscon 6) vs. NCAT’s results. Is there documentation as to why these two superseded systems would experience a change in transformation results?

NADCON 5.0 release 20160901 supersedes all previous versions of NADCON. Minor differences are possible between NADCON 5.0 release 20160901 and legacy versions. NOAA Technical Report NOS NGS 63 (PDF, 17 MB) provides detailed information on NADCON 5.0 release 20160901 (including why these differences exist), and the digital archive includes plots and data.
Is NCAT a replacement tool for Corpscon version 6?

NGS, the authoritative source for conversions/transformations grids, provides through its NCAT program the latest transformation grids for horizontal and vertical transformations. Industry or other agency conversion/transformation tools such as Corpscon version 6 (which is maintained by the U.S. Army Corps of Engineers) and others may or may not incorporate the latest grids. As such use of NCAT is strongly encouraged.

NGS Coordinate Conversion and Transformation Tool (NCAT) allows users to easily convert between different coordinate systems and/or transform between different reference frames and/or datums, in a single step. For coordinate conversion, NCAT allows conversion between lat/long/height, SPC, UTM, XYZ, and USNG systems. NCAT currently uses NADCON* to perform three-dimensional (latitude, longitude, ellipsoid height) coordinate transformations and VERTCON* to perform orthometric height transformations. Transformations are provided for a wide range of frames/datums and regions in the National Spatial Reference System. NADCON and VERTCON provide local error estimates for each transformation, and do not support transformations which are outside the boundaries of the supported areas (generally, CONUS, Alaska, Hawaii, Puerto Rico and the US Virgin Islands, American Samoa, and Guam and Northern Mariana Islands).

Please note that, although either orthometric or ellipsoidal heights can be used as inputs to NCAT, at this time NCAT does not convert between orthometric and ellipsoidal heights. Only orthometric-to-orthometric and ellipsoidal-to-ellipsoidal height transformations are currently possible in NCAT.

NCAT incorporates the capabilities of the following NGS computer programs, which originally were stand-alone products:

* See ChangeLog for information on the currently implemented releases of NADCON and VERTCON.

Version 2.1 View ChangeLog

Direct your questions and comments here

Website Owner: National Geodetic Survey / Last modified by ngs.ncat Dec 05 2023

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