Latest Contributions by BojanŠavrič

Hi @KevinBoes!  Yes, some ArcGIS systems do not allow horizontal and vertical coordinates to be in different units because the scale of tridimensional data is then inconstant. It is one of those “best-practice” rules. Tridimensional data should have the same units in all three directions. In general, when converting only heights and keeping horizontal positions in the same coordinate system, positions do not change. There are some rare cases when data needs to be converted to different positions in order to convert heights. In those, there could be minor differences depending on which transformation path is applied for the conversion. In your case, having data in the NAD 1983 StatePlane Nebraska FIPS 2600 (US Feet) (WKID: 26852) and converting NAVD88 height (m) (WKID: 5703) to NAVD88 height (ftUS) (WKID: 6360), it requires only unit conversion. Transformation NAVD88 Height (m) To USFT (WKID: 110026) would only change the units and your positions should stay the same as they are. So yes, there should be minimal effect or no effect at all with your conversion. Since you are writing a python script to populated height values, you could convert units yourself. If you do, just be careful you apply the correct conversion factor. 😅 If your heights are measured in NAVD88, you should use it. The alternative you talk about in your comment is the ellipsoidal-based vertical coordinate system called NAD 1983 (WKID: 115702). For all work that relies on gravitation and “correct water flow,” you should avoid using ellipsoidal-based systems since they are geometric, and they do not follow the gravitational forces. Best practice is to use some gravity-based system that is compatible with your horizontal positions. In your case, this is NAVD88 system. I hope this helps. ... View more

@JummaKhan: These projected coordinate appear to be in Web Mercator (3857):   ... View more

Hi @Esther_Morrow! Your difference in location is caused by using degrees-minutes-seconds format as they would be decimal degrees.  0 deg 18' S is not -0.18 deg, but -0.3 deg; and 130 deg 40' E is not 130.40 deg, but 130.66666667 deg.  If I use correct decimal degrees in ArcGIS Pro, the point appears on the same location as on Google Earth.  I hope this helps!   ... View more

Thank you, @Bernd_Loigge, for your question! The image of the GCS on the slide 13 is correct and intentional. Let me explain it… A geographic coordinate system is defined on an ellipsoidal surface. The center of the ellipsoid is still where the polar axis intersects the equatorial plane. Latitude of the point P is measured between the equatorial plane and the normal on the ellipsoidal surface at the point P. In general, normals on an ellipsoidal surface do not go through the center of an ellipsoid. They intersect the polar axis below or above the center depending on whenever the latitude is positive or negative. Exceptions are points on the Equator and at the pole. Their normals go through the center. The distance between the point P and where the normal intersects the polar axis (Q) is called the transverse radius of curvature. If Earth’s model would be a sphere instead an ellipsoid, then all normals would go through the center of the sphere. I hope this helps, Bojan ... View more