Question

Convert shp. to TAB

  • 15 September 2015
  • 5 replies
  • 9 views

Hi. Every quarter I convert a shp. to TAB and GDB and compare the size of each file to see if I had an increase or not.

 

This quarter I converted and I had an decrease on the size of the shp. and GDB, except for the TAB file:

 

 

I open the TAB file and nothing is corrupted, so my question is shouldn't the size of the TAB decrease also.

 

 

Please let me know your comments.

 

 

Thanks in Advance

5 replies

Userlevel 2
Badge +17
Hi,

 

 

Did you change the schema of the destination TAB dataset? e.g. data types.

 

 

Takashi
Hi Takashi,

 

The schema it's the same, also the data type and the lenght of the fields. I only renamed a field but keep the the datatype and the lenght.

 

 

I also checked that this quarter I have reduce the total of the vertices. It's a small diference.

 

 

Thank you so much for your input.

 

 

Best Regards
Badge +2

Hi @inesleite,

I have run some test on some data converting from shp to TAB, I have compared the same data with reduced features and the size reduces.

Perhaps you have duplicate records in your TAB file try using the duplicatedfilter on the TAB file and use fme_feature_type as a key attribute for the geometries or try other fields.

Try also deleting the old TAB and rerun the workspace.

Would you be able to share your workspace with us?

Badge +10

Of course you could have different different indexing in your TAB file. My suggestion would be to compare the last TAB file against the new one and check which of the file components has got the file size increase. If its the TAB file, you may now have some embedded metadata, the DAT suggests an attribute change, the MAP suggests more or more complex geometry, the IND, more or some Indexes.

I'm sure you are aware but, there are also two different MapInfo Writers, are you always using the same one? MITAB is the open source one, MAPINFO is the official one, both create subtly different outputs. (Not relevant in this case but the same is true of GDB also, with the API one being OS and the ARCOBJECTS one being official in this case.)

Badge +3

Of course you could have different different indexing in your TAB file. My suggestion would be to compare the last TAB file against the new one and check which of the file components has got the file size increase. If its the TAB file, you may now have some embedded metadata, the DAT suggests an attribute change, the MAP suggests more or more complex geometry, the IND, more or some Indexes.

I'm sure you are aware but, there are also two different MapInfo Writers, are you always using the same one? MITAB is the open source one, MAPINFO is the official one, both create subtly different outputs. (Not relevant in this case but the same is true of GDB also, with the API one being OS and the ARCOBJECTS one being official in this case.)

In addition to MapInfo format, .ID file is a link between DAT (feature attributes) and MAP (feature geometry) so in theory it increases with the number of features only.

 

Index is in the (optional) .IND file. The MAPINFO writer usually creates the indexes on columns where the source is indexed. It may be worth to check if there is any change in the indexes of the source shapefile.

 

 

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