Autoasm and Small Rivers/Streams

[Guest victorwest]

I'm getting used to AutoAsm (using Terrascene) and overall I'm finding it a very good program. Roads, rivers and lakes are easily produced. However, I was wondering if others had their own techniques for smaller rivers and streams when using Terrascene. The main data comes from USGS and I presume it covers almost all bodies of water. The result means that my bitmap contains a lot of "spurious" lines which I assume are non perennial rivers etc. Does anybody have a method that they use to delete the additional pixels or is there another source they might use which has less detailed water information and therefore less cluttered bitmaps?Victor

[Guest cwright]

Hi Victor, sounds like it's going well! I'm not an expert on TerraScene, but it may be possible to filter out the smaller streams. If not, another option would be to delete them manually. AutoAsm has a tool for deleting complete lines or polygons. After loading the bitmap into the editor, enable the editor tools and select the polygon tool. Right-clicking on a line will delete it. It will work better if you click on one end of the line. Of course, it could be a bit tedious if you need to get rid of a few hundred streams.... Best regards, Chris

[nudata 10]

It is very easy to eliminate all streams at the Terrascene level. Under Day Line Types click the None (Don't Draw) button. No color will be assigned and AutoASM sees no streams. There is no graduation for "small" streams versus "large" syteans. All or none. I would venture a guess that USGS has none either.I found the streams in Western Pennsylvania to be quite accurate. My issue was the depth of the channels was excessive. There is a parameter (I forget the where) that sets the depth. I believe it is default = 10 meters. I set mine to 3 meters.Dick Boley @KLBE

[Guest victorwest]

Many thanks for the replies Chris and Dick.Dick, yes I'm aware that I can exclude streams. However, what I wanted to do was to show only the larger streams. I guess though that this can't be done through TerraScene. Victor

[nudata 10]

If the underlying USGS data does not support different stream sizes you are indeed out of luck. Maybe someone knows of diferent data sets but conversions become and issue.Dick Boley @KLBE