X Y Data in Attribute Table Questions

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03-20-2019 11:54 AM
LGalyen
New Contributor III

I have 40k points the attribute table has multiple x and y fields all have different numerics.  None of them seem to match any coordinate system.

Can someone explain the format of these columns

Projected Coordinate System:    NAD_1983_StatePlane_Arizona_Central_FIPS_0202_Feet_Intl

Projection:          Transverse_Mercator

False_Easting:   700000.00000000

False_Northing: 0.00000000

Central_Meridian:           -111.91666667

Scale_Factor:     0.99990000

Latitude_Of_Origin:        31.00000000

Linear Unit:         Foot

thanks

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6 Replies
Egge-Jan_Pollé
MVP Regular Contributor

Probably the quickest way to get an answer to your question would be to contact the provider of the attribute table. They will (or at least should) be able to explain the content of the different fields.

Egge-Jan

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DanPatterson_Retired
MVP Emeritus

You truncated off the latitude and longitude coordinates, but your Xcoord and Y coord fields appear to be be lat and long

ie

75400100 Is your longitude which for some reason should be

-75.400100 for the western hemisphere (positive for the eastern hemisphere)

similarly for the Ycoordinate.

You could just add two new fields and do the appropriate conversion in the field calculator, then you will actually have coordinates that you can map as a Geographic coordinate system perhaps a GCS WGS84 if the datum is assumed as such

LGalyen
New Contributor III

That is what I thought but the first event field was populated with -44.100 etc then some didn't have -'s the next set had no +/- then last set were truncated....  but appreciate the help thank you

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MelitaKennedy
Esri Notable Contributor

Try mapping the points using the XADJ and YADJ fields and the given coordinate system: NAD_1983_StatePlane_Arizona_Central_FIPS_0202_Feet_Intl. The false easting (x value at center of zone) of the coordinate system is 700000. The XADJ field has values around 700k. I think the XCOORD and YCOORD fields have values in 100th of a foot. This is sometimes used in surveying or engineering.

I wouldn't trust the EVENT_X or EVENT_Y fields. The EVENT_Y field values are nonsensical. 

Melita

DanPatterson_Retired
MVP Emeritus

1/100th of a foot? now I have heard of everything

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LGalyen
New Contributor III

Melita  thanks, nonsensical is a perfect word to describe those numbers!!!    I spent several hours of mental work trying to understand them.   

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