I have tried making grid files from Google earth and tried the KML file to convert and upgrade the altitude values with TCX converter but Altitude cant be converted? is it really important to get the altitude values or i can use my species abundance data into Z column (transferring values as excel without conversion) to make my own elevation/contour?

I have tried putting my abundance values in Altitude column and it seems not the same as normal google view. I am using Surfer 13 for map making.