Monday, October 3, 2011

Z≠h

Today I want to talk about Z≠h.
I'm really sorry because I can not talk about % types of Geoid.
Next time I will talk about that thing.

Z = is measured from the center of the earth until the point on the earth surface.

h = is the distance above ellipsoid to the point on the earth surface.

Two difference things that sometimes make people confuse.

Some people believe that Z is equal to h but facts that they were absolutely wrong.

There are no such thing or probability that Z is equal to h because the are measured not at same starting point.

So, clearly state that “ Z IS NOT EQUAL TO h”.

Sunday, October 2, 2011

GEOID

Salam 1Malaysia..

Today I want to talk about
geoid..

Do you know about Geoid? Have Heard about Geoid before?

If you want to know, geoid is very important to determine Heighi and in other word it’s called as Ortometric Height (H).

There alots of definitions about geoid.

Some say that Geoid is undulating surface that always have changes. Do you that our land sufaces are moving? Although it moving in centimetres for a year it still moved.. It’s not static..

Geoid is also an equipotential gravity suface. It means that all the points on the earth share or have same gravity surface. Besides, Geoid can be define as the forceof gravity is perpendicular everywhere.

To understand about geoid are sometimes it become complicated.


As you can see in the picture above our earth surface called as topography and we have another two layer that are Geoid and Ellipsoid.

The Geoid can be above the ellipsoid or lower than ellipsoid. As I mention begfore the the Geoid is an undulating surface.

That’s all for today..

Next time I will talk about 5 types of geoid we need to know...

Salam...