Latest Contributions by MelitaKennedy

‎03-15-2019

Answered in a duplicate post: https://community.esri.com/thread/230160-where-can-i-find-this-coordinate-reference-system-wgs84-30n-cm-3w-in-arcgis

‎03-12-2019

It's all based on the GCS. Any of the NAD83 realizations are more likely to be using NAVD88, but it's not 100%. Depending on where the data is, the differences between the NAD83 realizations (starting with HARN) won't make much difference when using geoid12b. That is, ellipsoidal heights will differ depending on which realization is being used, but when using that location to interpolate the offset between ellipsoidal and geoid surfaces, should not make that much difference.

‎03-12-2019

Geoid models (converting between ellipsoidal heights and orthometric heights) are usually tied to a particular GCS, like geoid12b should be used with NAD83 (2011), but as Jim says, the gravity-related vertical coordinate systems/datums like NAVD88 and NGVD29 aren't strongly tied to a particular GCS.

‎03-04-2019

In ArcGIS Desktop 10.4.1, you can use the Project Tool to perform some vertical transformations like NGVD29 to NAVD88. You can't do anything on-the-fly in ArcMap itself, nor can you apply a vertical transformation to a raster. Melita

‎02-26-2019

The US National Geodetic Survey (NGS) is implimenting a plan to replace NAD 83 and NAVD 88 through a modernization effort. NGS’s main page on the subject: https://www.ngs.noaa.gov/datums/newdatums/index.shtml NGS has been very proactive in publishing information on the planned changes, and has had several summits to directly communicate with stakeholders and invite feedback. This year’s is on May 6-7 in Silver Spring, Maryland. https://www.ngs.noaa.gov/geospatial-summit/index.shtml Last year there was a special industry partner summit. We’ve had someone at all of these geospatial summits, and have met many of the NGS personnel who are involved in the effort. We are also attending or watching the NGS webinars related to this subject to make sure that we’re on top of the situation. NGS has stated that they will release beta versions of data, transformations, etc. ahead of the 2022 date. So far there hasn’t been anything that Esri can test. We plan to incorporate any new coordinate system definitions (geodetic, projected, and vertical) as they’re released officially. If NGS releases beta versions, we plan to check that we do not see any issues and that they can be used in the software. We have occasionally pre-empted an official release of transformation grid files or coordinate systems because supposedly the names and other information have been finalized and put the objects into a current software release. Then the names are changed and we end up having to change/delete/add the existing definitions. Because there are a lot of customers using US data, we want to be very careful adding these new coordinate systems and transformations for the 2022 modernization.

‎02-26-2019

Yes, that's correct.

‎02-25-2019

So all transformations are bidirectional / reversible. They have to be to support raster reprojection/transformation (we project extent and some points to create the output raster, then fill it by projecting sections back to the original to get the cell values). I need to work on documents for the US and Canada for the horizontal side--NAD83 and its realizations/re-adjustments. Melita

‎02-22-2019

NCAT is likely using NADCON 5 files which means it's stepping through these GCS: NAD 1983 (1986) to HARN (1994) HARN to FBN (2nd HARN, 1999) FBN to NSRS2007 NSRS2007 to 2011 All four would be file-based transformations. Esri currently supports 2 steps only so we can't use the same path. Instead, we're using a 2000 era conversion between NAD83 (it's closer to HARN/CORS96) to "WGS 84" the a 2nd transformation to convert from "WGS 84" to NAD83 (2011). So they're not equivalent paths and won't give similar answers. We plan to add the NADCON 5 files, hopefully this year. You will probably get closer answers by using 1st part NAD_1983_To_HARN_Nevada NAD_1983_HARN_To_NSRS2007_GEOCON_CONUS 2nd part NAD_1983_NSRS2007_To_2011_GEOCON11_CONUS This misses the conversion between HARN and FBN, unfortunately. Melita

‎02-20-2019

Gary, For your original question, a projected coordinate system is always based upon a geographic coordinate system (GCS). The GCS defines size and shape of the earth model being used, then the PCS describes how to convert it to a 2D surface/plane. Melita

‎02-20-2019

Yes, you're right. It was NAD 1983 Illinois West (US Feet). I checked one location for it yesterday, and didn't check a 2nd one. Melita

‎02-19-2019

It's the original WKID Esri gave to this object when we added it. EPSG has since added it, so we did a "code change" to 6457. Either number will work if you give the number directly rather than use a WKT string. 3436 is EPSG's number for NAD 1983 Illinois West (US Feet). I can't find 102672! Melita

‎02-08-2019

It looks like it's not finding an end-of-line character so you get one event with a lot of attributes. What happens if you do a save as of the .csv into a .txt file (make sure line wrapping is turned off to see if it shows the wrong formatting) and try importing that? Or pull the csv into Excel, again checking the formatting and importing or re-saving it out as .csv? Melita

‎02-08-2019

Hi Trevor, I'm a product engineer who focuses on coordinate reference systems (CRS). The csf file appears to be in a binary format and I don't have access to Geomedia or Oracle. We don't have a coordinate system called UTM "Extended" zone 13N. Since you're working with a file geodatabase, you can use the Define Projection Tool to assign a CRS to the data, or at least to the map/scene. Can you screenshot the coordinate system information from Geomedia so I can point you towards a similar/equivalent definition or how you would go about creating a custom CRS? I suspect that it's EPSG:2957, NAD83(CSRS) / UTM zone 13N or EPSG:26913, AD83 / UTM zone 13N. Thanks, Melita

‎02-07-2019

I replayed to the other thread. No, didn't make it. It's now on the list for 2.4/10.7.1.

‎02-07-2019

I am sorry, but it did not. Last year had a few, "Wow, I did not see THAT coming moments," which derailed some of my plans. It's on the list for 2.4/10.7.1. Keep your fingers crossed! Melita

My Ideas

Latest Contributions by MelitaKennedy

Re: Where can I find this coordinate reference system (wgs84 30N CM 3W) in ArcGIS?

Re: H & V DATUM TABLE

Re: H & V DATUM TABLE

Re: Vertical Datum Changes

US datum modernization coming in 2022

Re: Projection Workflow

Re: Projection Workflow

Re: NCAT vs ArcMap coordinate conversions

Re: Project tool not working

Re: Reading a PRJ file

Re: Reading a PRJ file

Re: CSV Display XY Issues

Re: ArcGIS Pro 2.3.0 asigning Spatail Reference to my Spatial data

Re: CGVD28 to CGVD2013 Transformation File Format

Re: Is it possible to apply a vertical datum transformation to a las dataset (*.lasd)?

Re: EPSG release and ArcGIS Projection Engine

Re: EPSG release and ArcGIS Projection Engine

Re: The vertical transformations WGS_1984_To_EGM96

Re: The vertical transformations WGS_1984_To_EGM96

Re: NAD83 to NAD83 2011 transformation methods

Coordinate Reference Systems

Alaska GIS Users