Validity test for a shapefile

#1

Hi,
Is there a simple and reliable way (or code) to test if a shapefile is valid?

Thanks!

#2

Hello @lang

There is a validation call for the Shapes in a Shapefile. Unless you are looking for something higher level.

Regards,
Jerry.

#3

Jerry,
Thanks a lot for the quick response! This is helpful, yet do we have anything higher level?

#4

Jerry,
Methods with built-in shapefile validation includes Shapefile.SaveAs, does it mean if a shapefile is saved successfully by using SaveAs, it is valid?
Thanks!

#5

Also, what is the easiest way to check is a file is a shapefile?

#6

Hello @lang

It is probably true in general that if you have a Shapefile already in memory, it is a valid Shapefile. Now that doesn’t mean all shapes within that file are valid.

So the first test is if you can successfully open a file as a Shapefile, then that’s probably the easiest way to know that it’s a Shapefile. You can then call FixupShapes, which will check the validity of each of the shapes within the file (there is also a Utils function of the same name).

And like you say, when you call SaveAs (which is often called on an in-memory Shapefile), it makes a call to validate the shapes prior to saving. Note that this function will also be creating a DBF file that had not yet existed, and will truncate field names to 10 characters, among other things. (In-memory Shapefiles can have Field names longer than 10 characters).

Regards,
Jerry.

#7

Jerry,
Appreciate it! Really helpful. So when I use Shapefile.FixupShapes, it’ll return true when all shape is fixed. it’ll create a new shapefile in memory and I don’t need to save it, right? So just check if returns true, the shapefile is good.

This is the first time I know that a dbf is created by SaveAs function.

Thanks a lot!
lang