There are two limits when uploading data.
First is the limit on the size of an individual file. Currently, the default is set to 100 MB per file. You can upload any number of files you wish, but if you would like to upload files larger than 100MB, Please contact us at firstname.lastname@example.org and we will increase the amount to you.
The second limit is the number of vertices on the dataset. This is set at 100,000 vertices for points and 20,000 vertices for polygons and lines. If you wish to upload a dataset that is larger than this, again, please contact us at email@example.com.