I want to create a fishnet based on the extent of individual polygons from a list of polygons. I plan on processing each resulting fishnets further.

I am maintaining a worldwide data set on Quarter Degree Grid Cells split into country level grids. I have previously used a python script to generate the grid cell sets. My workflow has been as described in an article on my blog. The point which breaks my workflow is first generating a world level fishnet, certainly when I am operating on a 1/8th degree cell level and below. I want to create the necessary fishnets on a country level instead. To support that workflow I need to know the following:

Does FME provide functionality to create fishnet polygons with a defined lon/lat starting point? And if so does that method accept scripted inputs so that this can be done based on a vector data source with n countries/regions defined?


You may want to look at: 2DGridAccumulator transformer it replaces the input features with a grid of two-dimensional point or polygon features having the spacing specified covering (at least) the bounding box area of all the features which enter the transformer.

  • The transformer does not seem to allow the user to set a starting corner for the calculation. So it seems like it ends up being rather arbitrary. 2dGridCreator allows coordinates for starting corner So what I will have to do is harvest east/north value and round off to my preferred starting point. Populate some variables and then proceed to make the fishnet. But is it even possible to add (iteration based) input variables from a data store? – ragnvald Mar 11 '14 at 4:28
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    Hi, im not absolutely sure about your workflow, but to my understanding you want to bring external variables to be used as input parameters in 2dGridCreator. If so than you could use a joiner to get data from data store or a even format writer eg. a csv file and feed 2dGridCreator parameters with values from the attributes of you external data store. Another path sometimes useful for mulltiple iteration is the usage of WorkspaceRunner. – Jorge Vidinha Mar 11 '14 at 12:38
  • Jorge, I added comments on workflow according to your questions. – ragnvald Mar 14 '14 at 21:29

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