Why is geometry being dropped when outputting to a MapInfo Writer in FME?

Question

In some instances geometry is being unexpectedly dropped when writing to a MapInfo writer. This occurs when FME has a conflict with the Format Attribute of 'mapinfo_type' which has been attached to a feature from a non-mapinfo source such as SQL Server Spatial. The conflict arises when the mapinfo_type is point or line but the feature it has been passed to is a polygon. Sorry I don't have enough reputation to post an image of a simple workbench so hope the URL works or the following description:

Description: It will happen if we use a SpatialRelator transformer to perform a simple 'point INTERSECTS polygon' exercise. If the base polygon features come from a SQL Server Spatial reader but the point candidates originate from a native MapInfo reader the 'mapinfo_type' format attribute of the points is transferred to the base polygon features (as this attribute did not already exist on the base feature). The result when writing out to a MapInfo writer is that FME sees a mapinfo_type of point on a feature which is actually a polygon and drops the geometry of any polygons that intersected.

We've worked around it by the following:

1. Write to SQL Server instead, or if native Mapinfo output is required do any one of the following:

2. Expose mapinfo_type on any offending MI input datasets then remove it just prior to writing to output,or,

3. add a Geometry_Coercer transformer to the MI input dataset and force it to polygons.

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Any comments on better solutions?

Answer 1

If you put an AttributeExpressionRemover before the SpatialRelator candidate port then you can use it to remove all incoming attributes starting with "mapinfo". That should prevent anything untoward being copied across.