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create isochrones from origin point grid

  • July 3, 2018
  • 5 replies
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craftydutchie
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I've been trying to create isochrones from a grid of points (shp, 1000m apart) that have the total journey times already associated with them (number format). I tried a 3D forcer and contourgenerator, but I just can't get it to work. I've popped a screenshot below. I'd be most grateful for some tips.

Thanks!

Renee

Best answer by craftydutchie

Ah! I think I've worked it out. The 3D forcer sets the travel time for each points as the elevation / Z value and this is then used by the contour generator. Thanks both for your responses.

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5 replies

gio
Contributor
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  • Contributor
  • 2252 replies
  • July 3, 2018

don't know what the data looks like, but if you don't get contours output, I'd gamble the group by might be at fault.

I assume the group-by isolates different "events" for which you are trying to create the isochrones?


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  • 719 replies
  • July 3, 2018

Hi @reneewsp,

There are two articles available in the Knowledge Center that may be of some help here: https://knowledge.safe.com/articles/30048/creating-time-and-distance-isolines-using-the-netw.html or https://knowledge.safe.com/questions/3397/drivetime-isochrone-from-multiple-points-of-origin.html

Other than that it looks to me that it is not the ContourGenerator but the 3DForcer you should take a look at first. From your snapshot I can see that the CG doesn't even seem to be processing any incoming features as there is nothing coming out of the rejected port either. So instead of looking at your CG I would perhaps add an inspector to your 3DForcer and check that the data being outputted here is correct and meets the requirements of the CG transformer.


craftydutchie
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  • Author
  • 8 replies
  • July 4, 2018

don't know what the data looks like, but if you don't get contours output, I'd gamble the group by might be at fault.

I assume the group-by isolates different "events" for which you are trying to create the isochrones?

Hi Gio, thanks for your response. The "Tot_Fastest" is the shortest travel time from that point to the destination.

 

 


craftydutchie
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  • Author
  • 8 replies
  • July 4, 2018

Hi @reneewsp,

There are two articles available in the Knowledge Center that may be of some help here: https://knowledge.safe.com/articles/30048/creating-time-and-distance-isolines-using-the-netw.html or https://knowledge.safe.com/questions/3397/drivetime-isochrone-from-multiple-points-of-origin.html

Other than that it looks to me that it is not the ContourGenerator but the 3DForcer you should take a look at first. From your snapshot I can see that the CG doesn't even seem to be processing any incoming features as there is nothing coming out of the rejected port either. So instead of looking at your CG I would perhaps add an inspector to your 3DForcer and check that the data being outputted here is correct and meets the requirements of the CG transformer.

Hi Holly, thanks for your response. The 3DForcer outputs all of the points but no field is added - I've added a screenshot below. I initially set the elevation at 0 so I changed it to one in case this did anything, but the outcome appears the same.

 

 


craftydutchie
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  • Author
  • 8 replies
  • Best Answer
  • July 4, 2018

Ah! I think I've worked it out. The 3D forcer sets the travel time for each points as the elevation / Z value and this is then used by the contour generator. Thanks both for your responses.