Model Builder

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04-21-2013 06:48 PM
SrinivasSanthanam
New Contributor
Hi,
I am a very new user to GIS,and currently I am having a problem running Model Builder,

I am trying to build a model which iterates over unique values of a field  and takes each of these values to calculate another field.
I am not able to get different values, but infact I am getting the same value for each row of that field.
My aim is to select a value for the field rooftop_twohundred and then convert that value into percentage by creating a new field       Percent. this has to be repeated for all the points (there are 14718 of those).
I tried to build a model but the field percent shows the same values. I am not able to proceed furthur beyond this point, and I am very new to GIS. Can anyone please help me out. i have attached the screenshot of the at tribute table and the jpeg image of the model.Can someone help me out, I would be grateful for that

[ATTACH=CONFIG]23693[/ATTACH]

[ATTACH=CONFIG]23694[/ATTACH]
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4 Replies
by Anonymous User
Not applicable
Original User: melanie_summers

Hi Srinivas,

Are all of the values multiplied by the same number to get the percent? If so, you don't need an iterator, the field calculator should be enough. If not, how is the percent being determined?

Best,
Melanie S.
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SrinivasSanthanam
New Contributor
hey, thanks. yes i figured that out, it is working.
I have another query.Percent field is obtained by dividing the rooftops_twohundred by the sum of the rooftops_twohundred (I used it as an expression to calculate field tool). I know it is a fixed number (9040), but since I may change the attributes and the sum will change. so i  do not want to change the sum value again and again in the expression. is there anyway where I can use the sum as an expression in the calculate field tool rather than changing it manually everytime the sum changes?
I do not know the basics of python script or VB. so I am not able to find an expression to calculate the percentage.
thanks for your help
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by Anonymous User
Not applicable
Original User: melanie_summers

Hi Srinivas,

You could possibly do this with Summary Statistics but I would want to play with your data to get it to work properly.

Best,
Melanie S.
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SrinivasSanthanam
New Contributor
Hi
Its a very large file and I doubt whether I will be able to upload it here.is there any other way of sending it to you
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