[gxnet]: Questions about grid derivatives.

[Aaron Balasch]

Hi everyone,   I'm just too curious. This morning, I was playing around with vertical derivatives. This is where the curious part came in; I wanted to know exactly what the vertical derivative was doing, like a lot of other things in the math world, there are more than one way of doing things. The vertical derivative is pretty straight forward but I still wanted to see for myself. I was kind of dissapointed that it the drevative process is hidden within a wrapper; GridVD_IMU(). Does anyone out there know the actual 3x3 convolution filter that is used. Also, to my surprise, I found that it appears that a 3rd degree trend is taken away from the grid. Is ths a common practice in magnetics or gravity processing?   I also remember experimenting with gridshad awhile ago which from what I would expect is similar, but not quite the same, as a horizontal gradient. From what I understand, the declination of the sun in gridshad is equivalent to the direction of the horizontal gradient, but what I can't figure out is where the inclination in to the horizontal gradient and how the result of the gridshad operation gives results between -1 and 1.   Can anyone offer any answers to these questions?   Thanks.       Aaron Balasch Sky Hunter Technologies Inc. Suite 101, 1725 10th Avenue S.W. Calgary, Alberta T3C 0K1 Phone: (403)228-2175 Fax: (403)244-7955 email: [EMAIL PROTECTED]