[pdal] FW: NITRO NITF

[Murphy, Robert T.]

Howard:

I appreciate your response. I confirms what I had thought.

I have been involved having to meet the requirement of wrapping LIDAR in
NITF for library ingest for over 5 years. I like your turducken analogy.
I have been  trying to been trying to move away from it all together.
Mechanisms exist for the files to be ingested into national libraries in
the native LAS format and we have developed an NGA XML based metadata
specification that is embedded in VLRs. This allows us to provide the
additional  required metadata in the LAS files, and not loose it when
the LIDAR data is un-wrapped. I was encouraged to see the NITF support
in PDAL which can provide the un wrapping without having to unwrap with
the specialized NITF2LAS software. With the increasing use of PDAL there
is more leverage to move to native LAS storage and provides the pathway
to support any future new LIDAR storage formats.

I use the NITRO NITF library (along with LibLAS) to develop software for
QC and data import of our NITF wrapped LIDAR prior to ingest. I had run
into similar difficulties in building. On Windows  and Linux versions I
statically linked in. It was always presenting challenges. I would like
to see your changes go in the NITRO repository. I have also had to make
some change to meet my requirements and there was not much activity by
the authors with the exception of the fairly recent 2.7 release. I would
have thought they would have liked to attract more help with project.

I saw the NITF reader support was provided by GDAL and that there was a
start on the writer. I had considered creating a writer as we had some
of the sources asking about a non-proprietary wrapping tool.

Thanks,

Todd



-----Original Message-----
From: Howard Butler [mailto:howard at hobu.co] 
Sent: Monday, November 18, 2013 10:11 AM
To: Murphy, Robert T.
Cc: pdal at lists.osgeo.org
Subject: Re: [pdal] NITRO NITF


On Nov 14, 2013, at 8:52 PM, Murphy, Robert T.
<ROBERT.T.MURPHY at leidos.com> wrote:
> 1. I am building PDAL under Fedora 19. I want to support NITF. Should
only the NITRO NITF library from github ( /hobu/nitro ) be the one built
to use with PDAL, or will it also work with the NITRO NITF repository
from SourceForge.  I see you use NITRO NITF version 2.7, but diff'ing
them show some source code changes.

The SourceForge version had a number of deficiencies, with the biggest
being that it didn't support dynamic linking properly on Windows (a
requirement of maintaining LGPL compliance). Additionally, the authors
weren't interested in a CMake-based build system and were happy with
WAF. I couldn't get WAF to work on *nix, let alone Windows, so I finally
gave up, dropped it into github, and rolled a CMake-based build system
that properly exported the symbols necessary to use Nitro on Windows
dynamically linked. I left most of the repository alone, however, to
ease merges back from the master tree. I hope some day the authors are
interested in my contributions, but what exists now at
http://github.com/hobu/nitro is sufficient for the LAS-in-NITF
requirements I have.

> 2. Using the /hobu/nitro repository, the build instructions indicate
to use WAF as is typical of NITRO NITF. When I ran WAF it threw an error
("build module not found"). However I saw cmake files and ran it and it
built with no problem. Is CMAKE good to go to build the lib? It only
produced dynamic linked libraries (libnitf-c.so and libnitf-cpp.so). I
tested it and it was working.

Yes the CMake-based build system is good to go, and is very likely going
to be the easiest to use. It doesn't have J2K detection and other things
auxiliary library support yet, because I only needed to write
LAS-in-NITF files to meet my obligations. LAS-in-NITF is the horrid
turducken you imagine it to be, and PDAL's metadata support is limited
to IDATETIM and a few other items. You'll have to read the source code
of drivers.nitf.writer for more information. Sorry there isn't more yet.

drivers.nitf.reader is implemented using GDAL's NITF support. This is a
little bit different than Nitro, and I'd like to someday rework the
reader to use Nitro as well, both for a simple story and implicit
compatibility. 

Hope this helps,

Howard