I have 14 layers, which are polygons. They represent the channel of a river at different periods. I need to fill the gaps that exist once I overlay the polygons, but I can't change the properties of the original layers because I need to reclassify the resultant polygon on the base of the colour in order to do more analysis. I have tried to merge all 14 polygons, but the new polygon doesn't have the same properties of each individual polygon.

Do you know how I could fill the gaps between the 14 polygons?



Finally I have done it by creating two layers; one by union all layers without gaps, and other by union the layers with gaps. Then, I used Symmetrical differences tool and I obtained the layer with gap polygons.

2 Answers 2


1) Create a new Feature Class (FC) in a File Geodatabase (FGDB). Making sure the new FC has the field and field types you need to capture the attribute data from the various 14 layers. Hopefully they are all the same.

2) Import the 14 layers into the newly created FC (R-Click FC, Load --> Load data...).

3) Start an edit session on the new FC.

4) Use the Auto Complete Polygon function to fill your gaps. This will create several new polygons in the gaps.

5) Once you've completed drawing the new polygons you can use the Merge function, under the Editor drop-down menu, to make all the new polygons into one multi-part polygon.

  • Thanks! I have a problem.. In the second step, when I load the layers, I can't do it because of this error: "All data source must have the same schema". All layers have the same field but with different names because they were created using another different layers. Do you know why I have this error?
    – Krahsin
    Jan 3, 2015 at 10:13
  • @Krahsin - At the end of Step 1) "Hopefully they are all the same." In part, the schema defines the tables and the fields in each table. If these are not the same then the Import function fails. IIRC you can fudge this somewhat in that shorter text fields can be imported into longer fields but Numeric fields, etc., need to be the same or the Import fails. I mistook your question to say you needed all the polygons under one Feature Class. From your Final Solution edit it looks like you have managed a work-around that bypasses that entirely. Apparently I misunderstood your question.
    – user23715
    Jan 6, 2015 at 19:07

An alternative way of achieving this is to convert each layer into a raster where the polygon is given a value of 1 the background 0. You then add all your rasters using the raster calculator. The resulting raster is 1 or more for where the channel has been and zero for where it has never been. You can then easily extract and convert the zero pixels back into a polygon. Another advantage of this approach is that you get a raster showing you where the channel has been over your time period. The only downside of this approach is that you will create a pixelated edge to your channel polygons converting back and forth between raster and vector.

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