AutoASM - Deleting Error Bits

[nudata 10]

During the edit phase the program shows which pixels on the bitmap are errors. left clicking in Point mode deletes the bad pixel. This requires a minor mouse movement and a left click. I just did South Florida with a very complex coastline and 1895 errors. I thought that an alternate delete function would be to allow the use of the Delete Key as well as the left mouse button. I believe it would be faster since AutoASM already knows the location of the bad pixel.Dick Boley @KLBE

[Guest cwright]

Hi, Dick, That's an interesting suggestion. Having to fix almost 2000 errors would take some time. Actually, the program won't always know which pixel is to be deleted. If it's an isolated pixel, then no problem - it could delete it automatically. But in other cases the program just knows there's an error but it requires user input to decide the action. It seems to me there are two areas for improvement:1. To automatically select the point for deletion wity the delete key as you suggest.2. To improve the REPAIR BITMAP function so the number of errors that have to be manually fixed is greatly reduced. I'll give this some thought! Best regards, Chris

[Guest cwright]

Hi, Dick, I took a look at it - and it's not at all easy. Also, if a specific error can be detected then it would be best to fix it automatically with REPAIR BITMAP. I did notice that redundant pixels that touch only one other pixel did appear sometimes. I thought I could fix that with REPAIR BITMAP - but it's not so easy. A single-pixel break in a line would also touch only one pixel. Automatically deleting such pixels turned out not to be a good idea. Suppose there is a small break in a vertical line. It would then delete the lower pixel. On the next line pass it would again see a 'redundant' pixel and delete that. It would continue enthusiastically deleting pixels until there were none left! I'll check to see if single isolated pixels get through BITMAP REPAIR - if so I can easily fix that. In general the task of SEARCH is to fix problems that require a superior intelligence - ie you and me! - and that would require an awful lot of Visual Basic programming to achieve the same end. Be sure to use BITMAP REPAIR before running SEARCH - it will greatly reduce the number of errors that have to be fixed manually. Best regards, Chris

[nudata 10]

Not surprising since I mulled over the logic while doing some other things and it seemed to always become a chain of unintended results. We need to get Todd Klaus back in action to make some fixes to Terrascene.....Dick Boley @KLBE

[Guest cwright]

Hi, Dick, when testing AutoAsm last year I did quite a few Florida squares and I think every one had at least some very obvious errors such as complete sections of large polygons missing. I did wonder whether this was due to a problem with TerraScene - or a problem with the original USGS data. It would be interesting to get Todd's opinion. Or maybe a question on the Fly! forum.... Best regards, Chris