I'm using ArcDesktop 10.2. I have 30 x,y locations that have 20 fields of numeric data, stored in an Excel spreadsheet. Some cells have no data, and I want those cells to be represented as null values when I convert it from a spreadsheet to a feature. I keep getting 0's instead of < NULL > when I convert the Excel spreadsheet to a shapefile. The ArcGIS help website says that in version 10.2, they no longer support null values in shapefiles. When I try to change the field properties regarding "Allow Null Values", it will not let me change the setting from No to Yes.
It's critical for a statistical analysis later on that the null values remain and are not converted to 0's. Is there a way to create a feature class that allows null values? There are some true 0's in the dataset, so I cannot simply delete all the 0 values using the Editing Toolbar. I could compare the shapefile and the original spreadhsheet cell-by-cell and manually remove the 0's that are actually nulls, but I figure there must be a better way.
Best Answer
Shapefiles, which use the older dBase specs, do not support null values. If you must maintain null values and you have to keep the file format to shapefile, you'll need to use a representative or 'nodata' value for it. This can be any value you wouldn't normally encounter or expect to encounter in the data, or that even falls within valid data's range, such as 999, -9999, or -32678. Again, really any value that could only mean one thing (ie, a coded value).