Becky & I have been working on our variable rate prescription calculations in Map Calc. One problem we run into is in map sets that do not have data for the full area within the boundry lines for every year of data. For example, say a farm has fields 1, 2, and 3. The first year all fields are planted to corn. The next year only field 1 is planted to corn. The third year fields 1 and 2 are planted to corn. How can we seperate out field 1 to do a three year corn average and field 2 to do a two year corn average and field 3 with a one year corn average. Then end up with a map that shows the above described results (the field averages) for the combined three fields on a single map.

Any suggestions?

We can treat each field individually and have 3 seperate prescription maps but the operators tend to be grumpy about all the files to go through when changing fields often. Also when doing this the "other" fields that have no data for that year get zero's averaged in and averages calculated which are wrong. If the operator goes into this "wrong data" field without changing over to the proper file with the correct data, he will be applying something that is wrong. It would be nice once the desired results are obtained for the individual fields the three could be combined to have a single prescription map. This may seem a little trivial but we do enough fields in a year if every one is split up the list of files becomes no small matter (on the order of well over a hundred files to choose from).

I don't know that I described the problem very well but I think any Map Calc users will know what I am talking about .

Map Calc is a wonderful program but it sure could use some updating of features. A "rubber band" selection tool to cut and copy stuff to different screens would be sooooooo helpful.

John