I have a question relating to a comment in a closed discussion (Does a value in srtm dem file refer to the center or corner of a cell?).
The comment was following:
"When talking about any DEM, it's resolution is important. SRTM has a resolution of 90 m for non US areas. Theoretically speaking, you can't really say anything about the height variation within that pixel. So just as PostGIS rasters (or rather All Rasters), it is the value for the entire area of 90m*90m, and not for just some specific point within that square. However, many interpolating algorithms, assume the height is for the center of the pixel, and will interpolate the heights for points in between the pixel centers."
Does this mean that it is not possible to estimate correctly the height/slope of the landscape from 90m DEM? E.g. if I have calculated slope based on 90m DEM. What is meant by interpolating algorithms, should one interpolate 90m SRTM to get correct height?