Hi Gary,
Attached is a test project to simulate the results.
When the program runs, it loads the line and points from 2 shape files in the data subdirectory. The line is oriented 0 degrees and the points fall along the line as can be seen in the map.
In the tool strip area, there is a text box that allows you to change the search distance of the GetFeaturesWithinDistanceOf function. After you set the value, click the button saying "Get All Points On the Line".
With 1000m default search, you will see 1 of the points is not found. If you set it to 500m, you will find 2 points not found. If you set it to 250m, you will find 6 points not found. When the search is big enough (~1250m), you get all features returned.
It is definitely an error with the method as you can quickly scan the debug output of the converted features of each InMemoryFeatureLayer and see that they have identical X coordinates and that all Y coordinates for the points are inside the line Y coordinates. Sorry the test code is full of reprojections, but in my project I do a lot of converting to UTM from spherical mercator and I wanted it to be as close to my project as possible.
This only happens when you are at exact line headings of 0, 90, 180 and 270.
I am using 6.0.0.149.
Regards,
Damian
ThinkGeo_ZeroHeadingError.zip (48.7 KB)