[Liblas-devel] Trying out liblas

[John Hayes]

Hello,

I just downloaded liblas 1.0.0b2 and am having some problems.

My end goal is get the scale factors for a bunch of LAS files.  I want
run the following shell code:

$ for i in *.las; do lasinfo $i | grep "Scale Factor X Y Z" ; done

The first problem is lasinfo always says the scale factors are zero.
It looks like the scale factors for these LAS files are around 1e-7.
The following patch fixes the printf formatter.

--- a/apps/lascommon.c  Fri Sep 19 15:17:56 2008 -0700
+++ b/apps/lascommon.c  Fri Sep 19 15:34:47 2008 -0700
@@ -416,7 +416,7 @@
                     LASHeader_GetPointRecordsByReturnCount(header, 3),
                     LASHeader_GetPointRecordsByReturnCount(header, 4));

-    fprintf(stderr, "  Scale Factor X Y Z         %.6f %.6f %.6f\n",
+    fprintf(stderr, "  Scale Factor X Y Z         %.6g %.6g %.6g\n",
                     LASHeader_GetScaleX(header),
                     LASHeader_GetScaleY(header),
                     LASHeader_GetScaleZ(header));


The next problem is lasinfo prints its output to stderr so the pipe
does not work.  This seems wrong to me.

Is it safe to change the fprintf(stderr, ... )s to fprintf(stdout,
...)s or should I make the caller pass in the output file stream?

-john

John Hayes