Latest Contributions by ChuckTurlington

Hello, I am using ArcMap 10.3. I selected the Projections and Transformations under Data Management Tools to change a NAD83 state plane coordinate to the WGS84 coordinate system.  I filled-in the Output coordinate system and then the under the Z Coordinate System tab selected WGS 1984.  Under the Environments tab I selected Z Values "same as input".  I thought ArcMap would have created the new data to a vertical metric unit but the new data still has the US feet value. I noticed a past post states that only ArcMap 10.4 has the vertical projection capability.  If this is the case, what is the "Z Coordinate System" tab for and is it possible to get my vertical elevation values projected from us feet to meters ? ... View more

Hello, I am in the attempting to understand the details behind the ellipsoid and geoid concepts as they relate to datums.  I understand some of the basic concepts of the ellipsoid and geoid, and my research suggests that the ellipsoid is defined with an anchored point based on the International Terrestrial Reference Frame (ITRF).  I have to assume this refers to an origin anchor point (earth center) but have to ask if this understanding is correct and is it one anchor point or several that are used? ... View more

Hello, I have been reviewing the basics of coordinate systems and trying to understand the role behind the Ellipsoid and Geoid.  I understand that the height difference between the ellipsoid / geoid, and the height between earths topography / geoid are related (h=H+N).  However, in my research I understand that a total station can be set to give elevation values on the Ellipsoid or the Geoid.  So I have to ask:  if the ellipsoid is an ideal shape of the earth with a simplified mathematical model, and I can work on the Ellipsoid grid to get my coordinates / elevations, why introduce the geoid at all? ... View more

Hello, I am using ArcMap 10.3. I have a question about the Ellipsoids surface and what it is intended to represent.  I see reference to the ellipsoid as approximating the earths surface but I also see the Ellipsoid concept as approximating the geoid surface.  So I have to ask: is the Ellipsoid intended to approximate the topography of the earths surface or the geoid surface ? ... View more

Hello,   I am using ArcMap 10.2.2 (though not pertinent here).   I am trying to understand the basics of a coordinate system Datum and Transformation, but have a question, as follows:  I information on computing a coordinate datum transformation using the "GPS Vector Components method," to perform a Transformation.  However, my information does not contain any visual graphics explaining the components involved, such as delta x,y,z, h, ecef origin, etc.   So I have to ask: Does ESRI have in their archives, white papers on this subject that give clear steps, relationships and graphic explanation of the components so I know that I understand completely and not missing a detail? ... View more

Hello, I am using ArcMap 10.2.1. I have displayed some contours from a DEM and right clicked on the contour layer to select Export Data.  The USGS NED metadata states the data coordinate is NAD83, vertical datum is NAVD88 and the Altitude distance units are Meters.  The ArcMap data frame coordinates are set to NAD83, South Carolina, International Feet.  In the export dialog I select "Use the same coordinate system as: the data frame," and select the output location and shape file format.  However, when I import the contours into CAD the horizontal location of the contours appears correct but the elevation of the contours appears to be in meters.  What is the best way to export the contours so they have the correct coordinate and units? ... View more

Hello,   I am using Esri ArcMap 10.2.1.   I need to qualify an aerial image in my notes on a figure.  I recognize the aerial stamp (credits) at the bottom of the figure but it does not contain a date the aerial was last updated.  Is it possible to find the date of the aerials that get downloaded from the Add Basemap button in ArcMap? ... View more

Hello, I am new to ArcMap 10.2.1 as a beginner status. I want to import an excel csv file into AcrMAP containing point; northing, easting ,elevation and description data.  What is the best workflow for accomplishing this type of import? ... View more