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Sorry if the question is too broad or not exact, but I'm pretty new in this area and not really sure about the namings and so on.

I have got an MS Access Personal Geo Database which is created either by ArcGIS Desktop or ArcSDE (I'm not sure as there is no clear statement about it on the source). This DB contains a table with a column named shape which is supposed to be Polylines with M value according to the manual. Now I want to convert these polylines to something more usable specially if possible GeoJSON.

Unfortunately I can't decode the binary format in this column, some of them start with these 8 bytes: 17 00 00 00 which is according to this PDF the code for a PolyLineM but some other records (most of them) start with these 8 bytes: 32 00 00 60 which seems to be no valid value for any shape.

Also trying to open the binary data using tools that support ESRI's shapefile format results in errors which I think is obvious because it is not a full shapefile.

Can anybody point me to a Java library or another open source solution that can convert these records at least from command line? or at least tell me what format should I look for if I want to convert these records?

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The simplest option is to use ArcGIS to export GeoJson rather than try to use a third party solution to read the binary data. Use Features To JSON and ensure you check the output to GeoJSON option (or specify it in the python code if you are going via a coded solution). Also not the include_M_values option too.

If you don't personally have access to ArcGIS then just have your data supplier re-supply as GeoJson (as they clearly do have ArcGIS).

Without ArcGIS, you could use GDAL (ogr2ogr) to do the conversion. See an example here. Just note this documentation for Personal Geodatabases.

You can find the specification for GeoJSON here.

  • that would be the easiest but unfortunately impossible. I don't have ArcGIS and the supplier is publishing these information publicly and would probably won't have the flexibility of changing source data for the sake of one user. The thing is also that I prefer the parsing and conversion to happen in an automatic process that don't need manual intervention. – mohamnag Jan 30 '18 at 9:58
  • but is this format documented anywhere? does it have a name? ArcGIS is using the title "feature" combined with "binary" for so many different things that I'm not sure what is what – mohamnag Jan 30 '18 at 10:01
  • See my edits above – MappaGnosis Jan 30 '18 at 11:49
  • ESRI uses a proprietary binary format for their Geodatabases and its not the same as in Shapefiles. Sometime Polylines are stored as Multipolyline, may that's the cause for different byte values. As GDAL is open source, maybe you'll find a solution inside the source code. More informations can be found here: loc.gov/preservation/digital/formats/fdd/fdd000294.shtml – Andreas Müller Jan 30 '18 at 12:02
  • hence my comment about using geodatabases through ogr2ogr. – MappaGnosis Jan 30 '18 at 12:15

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