Merging Polygons together

Is it true that to merge 2 polygons together they need to be touching in some way???  If this is so, it is a major weakness for my application.  Farmers have irrigation sets that are hooked together in separate fields yards from each other.  Why can't we hook then together in Global Mapper.  If a farmer can do it, why can't GM???  In 20 year old MapInfo this can easily be done but apparently not in latest and greatest GM.  I hooked then together in MapInfo and imported them back to GM -- but, when I did the polygons were separated.   When looking at fertility and thermal data and then overlaying this data with irrigation sets to identify issues, it would be nice to see an entire irrigation set and not just pieces of a set. 

Answers

  • geomanniegeomannie Global Mapper User Posts: 208Trusted User
    I am not sure what you mean. If the question is, can you combine separate polygon shapefiles into one editable entity, while still being displayed as as distinct features?, then the answer is yes. Select the polygons and use the "crop, combine" tool. If the question is, can I create a polygon that encloses my shapefiles?, then the answer is also yes. Select the polygons and then use the advanced feature creation tool, create coverage areas.
  • Neither method does what I want to do.  Please read what I wrote to MacKenzie at GM to get a better idea of the problem. 
    Lets assume you have 2 lawns - one in the front and one in the back and both these lawns are fed by one pump that irrigates 18 to 20 acres at a shot.  Because the pump is so big, you need to do both lawns at the same time and also several of your neighbors lawns together too at the same time all with front and back lawns.  Now let's take our farmer who farms 800 acres and is doing 20 acres at a time and the fields he's irrigating are sometimes together and sometimes maybe up to a mile away -- all from this same well.  We get a mapping project and decide to use Global Mapper to sort this whole thing out and keep in mind we have 1 well and 1 water meter.  Do you see how our inability to put disjointed (not together) polygons (lawns or fields) together could present problems???  This is what I was getting at with my first request from you several emails ago.  MapInfo can do this and I'm pretty sure ArcGIS and do it as well.  Many thanks for reviewing this problem together with me. 
  • bmg_bobbmg_bob Global Mapper Programmer Posts: 2,135
    Hello,

    It sounds like you might be looking for the function to group area features together. In the Digitizer, select the areas you want to group, right-click, and select Advanced Feature Creation Options -> GROUP - Create Multi-Part Polygon from Selected Area Features.

    Please give that a try and see if it is what you are looking for.

    Cheers,
    Bob
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