Question regarding Dissolve and its "Create multipart features" parameter

[JillClogston]

Hi community!

I need to backpedal to my dissolve question from earlier (for reference):

I have a table of whale sightings data with dates, group IDs of the whales seen, coordinates, and many other fields. I need to do some analyses on different whale groups looking only at the days present in a geographic region rather than each sighting of a group - some whale groups will split during the day and will be counted as two different sightings, but we only want to count those as one (hopefully that makes sense!).

I tried to use the dissolve tool which ran fine, but the resulting attribute table contains only 3 or 4 of the fields from the original attribute table which has 31 fields. I would like to retain all fields. I've tried the Pairwise dissolve as well with the same result.  How can I accomplish my goal without losing fields?

When running the dissolve tool, I need help visualizing what selecting the multipart features parameter is doing. My original table has 2132 sightings. If I check the multipart features parameter when running the Dissolve tool, the new table returns 2049 sightings. If I uncheck multipart features, the new table results in 2126 sightings. The dissolve fields that I am using are the sightings date and the whales' group ID.

Why two different results?

Thanks in advance!
Jill

[HusamJubeh]

Hi

If you want to keep all the fields, the dissolve tool keeps only the used fields and deletes the rest of the fields. To retrieve the rest of the fields, you can create a spatial join and match the fields through the field used in the dissolve, but here you must check the results. They may be correct for you or have an error rate.

Because the joining operation in the spatial join tool here is one to more

[JillClogston]

Thank you Husam. 

I'm trying to understand what the difference is between checking the "Create multipart features" parameter vs not checking it when dissolving as when I did it both ways, it returned two different whale sightings counts. 

[LucasChaparroVasconsellos]

Create multipart joins elements with the same field your dissolving that are spatially separated. That's the behavior when dissolving shapes