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enter image description hereI'm using ArcMap. I've read the messages related to this topic but they don't take me far enough.

Most of the advice is related to species distribution, but I need to create a species richness map. I need to be able to say, for example, that in grid cell P there are 5 species (a to e), and in grid cell Q there are 22 species, even though in P there may be 200 records for species a, 100 each for species b , c and d, and 10 for species e. I'm simply wanting presence/absence of species, then a count of presences in any one grid cell.

So:

  • I have created a fishnet 1 deg x 1 deg for Australia.
  • I have 5 shapefiles for the separate species, but I also have a single shapefile with all the species in it (AS IN THE IMAGE ATTACHED). Each individual record has lats & longs.

I have tried to merge the shapefiles and the fishnet by doing a spatial join with ONE_TO_MANY, but the resulting attrib table is not listing or counting concurrent species.

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    Hi there, could you edit your question to include the software package you are using? Could you perhaps also post a few screenshots of the attribute tables for the species? It would be beneficial to see how your shapefiles are setup. May 7, 2018 at 6:21
  • Thanks KA, I have now updated the question as you suggested. May 8, 2018 at 3:15

1 Answer 1

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  1. Create an ID column for the fishnet if you dont have one (Add field, Field Calculator or Edit).
  2. Spatial Join with the merged species points as target features and fishnet as join features with options JOIN_ONE_TO_ONE and Keep all target features.
  3. Delete Identical with spp and fishnet id fields checked
  4. Summary Statistics with COUNT on spp field as statistics field and fishnet id as case field
  5. Join the resulting table back to fishnet and export to a new feature class to make the join permanent

enter image description here

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  • Hi Bera, thanks for your information, but I've tried a dozen times and cant get it to work. It seems OK up to the last stage ... Is there some small thing I may be doing wrong? May 11, 2018 at 5:12
  • Ok. Step 4 or 5?
    – BERA
    May 11, 2018 at 5:38
  • Step 5. I've tried exporting back to original fishnet, but also to the one created in Step 2. May 11, 2018 at 6:07
  • You need to join the output summary statistics table from 4 to the original fishnet feature class. Then right click the fishnet feature class and export to a new fc. desktop.arcgis.com/en/arcmap/10.3/manage-data/tables/…
    – BERA
    May 11, 2018 at 6:10
  • Bera! I've done it! The missing step was in the initial Spatial Join - need to choose ONE_TO_MANY, and then everything flows from there! Thanks so much for your help because it gave me the sequence of steps that I then had to tweak. Brilliant! May 15, 2018 at 5:18

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