Working with incorrect coordinates

[EninnaLuli1]

I recently worked on a project where I had to map out 70 location sites in a city.

The latitude and longitude were given to me by the client.

When I first mapped out the locations, I assumed the coordinates were correct since they all fell within the city.

However, I decided to check the latitude and longitude of each location and compare it with street view in Google Maps. I noticed that most of the longitude and latitude were incorrect. They fell within the city but in incorrect locations within the city (I also had corresponding description of each location and pictures and they did not match with what I was seeing in Google Maps)

Now, I had no problem checking each site in Google Maps since there were only 70 locations.
But I was wondering... What if I had hundreds of hundreds of  locations to work with? How would I be able to check if coordinates are correct (obviously if the coordinates show me a different part of the world it would be obvious, but what if it is like my situation above where they look like they are in the right place and SEEM correct?). Is it my responsibility as a GIS person to figure this out if the client gives me incorrect data?

[FC_Basson]

It might help if each point has an address related to it.  Then you could at least try to validate with the Reverse Geocoding tool: Reverse Geocode—Help | ArcGIS for Desktop

[JoeBorgione]

Would the 'hundreds' have addresses as well? If so you could geocode them and compare the results to the xy coords provided.

[MicahBabinski]

In general, if you want to automate the process of typing an address into Google Maps and retrieving the coordinates (or the reverse), the Google Maps Geocoding API is the way to go. With a little coding you can retrieve, compare, and correct the coordinates in bulk. There is a bit of a learning curve to figure out how to make calls to the API and manage the results. Python is quite handy for this, especially if you want to roll the functionality into an ArcGIS geoprocessing tool. There are a lot of resources out there to help you get started.  When I last used it about a year ago you could make 2,500 calls to the API every 24 hours for free.

As for your other question:

Is it my responsibility as a GIS person to figure this out if the client gives me incorrect data?

...that's a tricky one! In my opinion, if your agreement was based on using data collected by a client, and this arrangement was factored into your fee, then you should not be held responsible for the impact of the client delivering erroneous data. I am guessing that would need to be laid out clearly in your contract, but I am not a lawyer, so don't take my word for it.