Maps: Does the distance between two points in absolute height calculate?

Question

Is the spatial Postgres plugin or any spatial package in this way affecting the height when calculating the distance between two points?

I know the spatial packet factor in the approximate curvature of the earth, but if one place is on the top of the mountain and the other place is close to the sea, it seems that the calculated difference between these two points will be very different if the height difference was not taken into account.

Also keep in mind that if I have 2 points at the same height of the ocean, but there is a mountain between the two points, this should take into account the package of distances.

Answer 1

These factors are not taken into account at all. What for? The software only knows about these two functions (two points to which you get the distance, the sphere / spheroid and the anchor / projection coefficient).

To do this, you probably need to use the developed linestring, in which you will associate your point with n vertices, each of which will be a sign of Z.

Imagine this (free WKT): LINESTRING ((0,1,2), (0,2,3), (0,3,4), (0,10,15), (0,11, - 1)) .

Having asked the software to calculate the distance between each vertex and summarizing it, we consider the variations of the terrain. But without something like this, it is impossible to compare the bumps in the area.

All GIS software cannot by themselves determine what these disturbances are in the area, and therefore not take them into account.

linestrings () , ArcGIS ( ), ( ) , , NASA ( SRTM). , X Y Z, . , , , , . , Z .

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Answer 2

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GPS, , , , , GPS-, ( GPS , ).

Answer 3

PostgreSQL . .

, 3D, .. Z, .

PostgreSQL , .

SELECT ST_DISTANCE (ST_POINT (0,0,10), ST_POINT (0,0,0));

, Z, > 0; , Z, .

SQL SERVER 2008, , , . SQL SERVER .

: PostGIS

Z ST_MakePoint. 4 (X Y Z M). St_POINT (X Y)

http://postgis.refractions.net/documentation/manual-1.4/ST_Distance.html ST_DISTANCE = 2D-

ST_DISTANCE_SPHERE ( - ) http://postgis.refractions.net/documentation/manual-1.4/ST_Distance_Sphere.html

ST_DISTANCE_SPHEROID ( ) http://postgis.refractions.net/documentation/manual-1.4/ST_Distance_Spheroid.html

ST_POINT http://postgis.refractions.net/documentation/manual-1.4/ST_Point.html