Help with choropleth mapping...

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11-19-2010 06:30 AM
charlotterobin
New Contributor
...I am new to this so please bear with me! I am trying to make a map of how many passports are checked per county in the UK. I have a table with my grid references (eastings/northings) county and number of checks, which I have added as x,y data onto my map of the UK. I know I need to join my table and basemap to make a choropleth map, however I seem to be having a few problems when I do this. Some of the counties that have definitely checked passports are showing up as "0". When I use the identify tool and click on the point for that data, it appears that somehow the data has got mixed up i.e. Lancashire has checked 500 passports but when I click on the point that is in Lancashire it actually thinks it is London and has no passports!

Is this something to do with the projection? I have double checked and the projection is the British National Grid so not really sure what is going wrong? If anyone could offer some advice that would be great!

Ps I have done plenty of other maps without this problem, for some reason it just doesn't like this dataset!

Thanks :)
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3 Replies
DanPatterson_Retired
MVP Esteemed Contributor
Have you tried the join on unprojected data?
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charlotterobin
New Contributor
I have just tried and no it still has the same problem :(
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DanPatterson_Retired
MVP Esteemed Contributor
Perhaps the -ve was left out of the Lancashire data putting it to the east of 0 Long.  spatial join should be by coordinates, so I would check file separately in its own dataframe to ensure that the unprojected coordinates line up where they should
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