what is the convention for choosing location coordinates

If you find map errors you should report them to http://www8.garmin.com/cartography/mapSource/errorForm.html. For custom pois on this site just click on the users contact and report them to the author.

As for the standard for setting coordinates for the custom pois.A lot of users like to use the alert feature on their unit.For that to work you need to set the alert close to the road you are traveling on.The coordinates should be no more then 50 ft off the road based on most posts on this site.That is why the rest stops have the coordinates set to the entrance.Of course if the location you are plotting is off the road a ways this would not be practical.Using Google maps you can move the markers around to obtain better coordinates.Sure other views on this and would be a good topic to post on.

I don't know if there is any standard for the location coordinates. Take the state parks, there are some POI files that use the center of the park as the coordinate, others use an entrance to the park, while even others will use the park visitor center as the location coordinate.

I was hoping there were some 'official' guidelines to avoid having everyone decide for themselves how to choose a location for different types of things. I was especially wondering for stores and such located in open shopping mall or strip mall areas.
Without guidelines, you have no clue what the creator was thinking.

There was a discussion here a while back about POI standards, but the discussion was limited to what information should be in the POI file rather than the geocoding.

As far as picking a location to code, it is pretty much up to the file creator and will vary depending on the type of file being created. Often coding the front door is not the best solution as other have noted. With the unit attempting to route using the fastest or shortest route, you may end up being routed into areas such as loading docks or mall service areas. Setting the location as an entrance from a major street would be a clue the destination is someplace in the mall area, now find a parking place or do a little searching on your own. If it gets you close enough you can see the location, so much the better, but if it guides you to a mall entrance, that's OK too.

When the POI entry is created, a note can be put in the description saying "Valley Mega-Mall" or other directions that help with the geocoded location.

If I know that a store is in the mall, I will try and add a comment on the second line of the address to say Great Plains Mall - 2nd floor or something. The other possibility is to have a auto coordinate and a ped coordinate. That way you could drive to the parking lot and then foot it over to the front door of the store. It does get hairy in those mega malls....

Daniel

I use flash earth and get the coordinates for the parking lot entrance.