Coordinate System Jargon: geoid, datum, projection
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- เผยแพร่เมื่อ 28 ก.ค. 2024
- The road to choosing custom projections is not paved with sundrops and lilies. It is time to start learning the nuts and bolts of coordinate systems.
Minute Markers:
0:27 Geodesy, the geoid.
1:10 Ellipsoid, geographic coordinate system.
2:09 Can't effectively measure with ellipsoid.
3:21 Planar coordinate system.
3:49 Geodetic datums.
5:41 Projections.
6:47 REMEMBER this, degrees vs. linear units.
7:10 Three types of projections.
7:32 Recap.
All images included are in the public domain, though the geoid image was originally created here I believe (correct me if I'm wrong):
www.esa.int/spaceinimages/Imag... - แนวปฏิบัติและการใช้ชีวิต
Very good video. Clear and clean explanations. Great usage of mouse to point to images along with useful commentaries. Thank-you so much!!
This video helped me wrap my head around these ideas a little better. Thanks a bunch! I'm thinking I'll be coming back to your channel often!
Wow - you explained these complicated concepts so well. Thank you!! (regards from India)
Overall, a nice intro. Clean graphics and an accessible presentation.
That said, I offer that a geoid model is not a snooth mathematical model (like an ellipsoid is), but one derived from measures of gravity. Also, the 'NA' in NAD83 does not indicate North America, but the North American tectonic plate. You might not need to cover NAD83(1992) vs. NAD83(2011) in an intro course, but it's worth planting the seed that ongoing plate movements do prompt periodic updates to our spatial reference systems.
+Scott Drzyzga Thanks so much for these thoughts! Keep them coming. I'm continually updating material. Thanks for taking the time to respond. Cheers, Ben
+Scott Drzyzga -- thanks again for this comment, I went through a closer inspection. I especially appreciate the clarification about NAD 83. I will have to update that in future videos.
As for the geoid, I think you'll find that I do describe it as a geophysical approximation based on the gravitational field. At -1:14- I mention the ellipsoid as being the "smooth mathematical model" for creating a geographic grid.
I would welcome any comments you have about terminology and presentation on any other videos I have, I'm working on creating more that describe the process of selecting proper projections.
Thanks so much for taking the time to respond! Comments and critiques are always helpful.
Cheers,
Ben
Well explained, pleasant way of talking. Thanks for the video!
Thank you! This explanation really helps me to understand the different models of the Earth
Thank you for summarizing 4years of survey engineering college ha. Good work friend.
Thank you, sir, for this video. It is fruitful to me.
Good job. Easy to understand
Thanks Ben! Yeah, I think I haven't heard it pronounced that much (mostly read) since college. Someday I'll get around to changing that. Cheers.
great explanation
Amazing video!
amazing greaaat work !!
Very helpful. Thank you
Great video, examples, explanations. Thanks!
Beautiful.
Excellent video! Keep on the good work!
Thanks! Glad it helped, and thanks for subscribing!
Can you help me understand the difference between Earth Gravitational Model 1996 and INDGEOID and how regional GM models are derived?
Excellent
Solid video!
Why we need to fit ellipsoid to geoid?
Do you mean ellipsiod is necessary for any projection?
Good stuff. Keep making videos, but perhaps get a better mic. You can get them cheap at a pawn shop, along with a cheap interface for like less then 100 bucks bro!
"don't get too bent out of shape just yet" hardy har har
This is genius.
Great
I was lost until I found you.
ge-odd-uh-see, not geo-deh-see ;P great video though!
Ben Patton Exactly, I was in the Geodetic Survey Squadron.
Gyar.. that dang schwa sound and putting the wrong stress on the wrong syll-ah-ble. Thanks though Ben! I'll update that in the future. Must have heard it pronounced wrong or only ever read it.