PostGIS - ST_InvDistWeight4ma

PostGIS을 통해 IDW 기법을 배울려고 준비중이지만 너무 어렵다 ㅠㅠ

PostGIS

http://postgis.net/docs/RT_ST_InvDistWeight4ma.html

IDW 설명

https://gisgeography.com/inverse-distance-weighting-idw-interpolation

역거리 가중치 방식을 사용하여 픽셀의 보간 값을 계산하는데... 

예제가 없으니 어떤 방식으로 사용이 가능한지 이제부터 찾아봐야겠다 ㅠㅠ

Synopsis

double precision ST_InvDistWeight4ma(double precision[][][] value, integer[][] pos, text[] VARIADIC userargs);

Description

Calculate an interpolated value for a pixel using the Inverse Distance Weighted method.

There are two optional parameters that can be passed through userargs. The first parameter is the power factor (variable k in the equation below) between 0 and 1 used in the Inverse Distance Weighted equation. If not specified, default value is 1. The second parameter is the weight percentage applied only when the value of the pixel of interest is included with the interpolated value from the neighborhood. If not specified and the pixel of interest has a value, that value is returned.

The basic inverse distance weight equation is:

k = power factor, a real number between 0 and 1