Clipping layer, zero output

[EricBrossman]

Hello everyone,

I'm having the same problem with my data set.  I had converted raster data from USGS GAP data into polygons and I was clipping buffered polylines from the layers.  Everything was working fine until I went to clip another polyline and then I got the zero output warning.  As far as I know everything is set to WGS 1984(the data frame, datum, coordinate system).  I tried merging all the polygons into a single polygon but I still have a zero output.  I tried turning off the background geoprocessing and disabled the Windows Indexing Service but that did not work either.  Everything else said to check the Extent environments to see if everything looks right.  I do not have a lot of experience so I'm not sure what to look for but I have a feeling that my problem lies there.  It's unusual that everything would be working fine for days, carrying out the same processing, and then suddenly not work.  I'm hoping someone can give me some guidance, thanks again.

[DanPatterson_Retired]

every layer has properties which can be accessed by simply right-clicking on the layer, selecting properties to bring up the properties dialog.  The extent information is under general (I think! poke around on the left of the dialog) and it will show the left, right, bottom, top of the layer's input geometry.  In order to clip etc, the extents must intersect at least.  Sometimes things go wrong when people have data in decimal degrees in a dataframe and are trying to clip using a layer which is in projected coordinates, even though things 'look' like they overlap in the dataframe.  It is not whether they look like they overlap, but whether the coordinates physically overlap that is important.  You need to confirm that the source and clip files are in the same coordinate system and that they indeed overlap in their extent.

[EricBrossman]

Thank you, Dan,

I made sure all the layers (the data frame, points, lines, buffered lines)had the same geographic coordinate system(GCS WGS 1984).  The data layers I'm importing from the USGS GAP program come in NAD 1983 Albers(A projected coordinate system)  I did a transformation on the GAP to GCS WGS 1984.  I have the lines buffered out at 30m, 300m, and 1000m to clip the GAP layer.  I got results for the 1000m clip but I get an "invalid topology incomplete void poly" for the 30m and 300m.  I ran a repair geometry tool on the layer but I have the same results.  I think I resolved the extent issue but of course another issue arises.

[DanPatterson_Retired]

Geographic coordinates are nice for storing data but I personally project my data to an appropriate projected coordinate system prior to doing any working involving 'geometry'.  why don't you project everything to albers, since projected coordinates are generally better when working with buffers and other geometries unless your area is incredibly large and you are using geodesic buffers.  It would be interesting to report the geographic extent of your study area so people can get a handle on what you are working with geometrically.

[EricBrossman]

I tried that but it didn't work but I'll play with it some more.  Yes, my study area is quite large and the buffers are geodisic.  I'm tracking dispersal of captive reared Barn Owls.  They were released in northeastern Illinois and they've dispersed as far as Colorado, New York, Michigan and Louisiana(Left -102.491944dd, Right -73.852500dd, Top 44.595000dd, Bottom 29.711667dd)

[DanPatterson_Retired]

ok... given that, and if the input geometries are correct, I would recommend you do it in pieces to try to narrow down where the error is coming from, although I cana't see a buffer trying to clip an empty geometry unless it is completely within open space (aka water, another country like canada), so have a look at the buffers and what you are trying to clip and run a sample area (say 1/4), If you make selections, selections are used when using the clip tool and the geometry being clipped

[EricBrossman]

I was clipping them by state and things were working fine until I got to

one particular state. Is there a way to break them down smaller? I'll look

at the inputs again.

[DanPatterson_Retired]

select the state out and make it its own layer, do the same with the overlapping buffers... if any and use those