TURTLE v0.11

This release adds gradient estimates and patches some bugs

• The turtle_map_gradient and turtle_stack_gradient provide gradient estimates w.r.t. map coordinates.
• Bugs have been patched in turtle_stepper concerning local transforms for maps.
• .asc files are now assumed to be in reading order.
• .png files now use full numeric precision for metadata.
• A turtle_stepper_reset function was added in order to manually reset the stepping history.

TURTLE v0.10

This release uniformises the output of turtle_stepper_step.

Improvements

• The turtle_stepper_step function now returns the same data when using a single layer or multiple ones. The size 2 index and elevation values are filled with the indices and elevation values of the surrounding layers.

TURTLE v0.9

This release allows differed loading of libpng or libtiff, whenever not available. It also patches some minor bugs.

Improvements

• Differed loading of libpng and libtiff using dl. The old behaviour (hard linking) can be obtained by setting TURTLE_USE_LD=0, e.g. for a static build. Note that version >= 1.4 of libpng is required in any case.

• Patch a seg fault when loading empty stacks.

• Patch ECEF conversion for on pole positions.

TURTLE v0.8

This is a minor release providing a reader for ASC files. In addition CI has been migrated to GitHub.

Improvements

• The ASC file format is now supported when loading maps.
• CI integration has been migrated from Travis to GitHub. The API documentation is now built and updated automaticaly on any push to the master branch.

TURTLE v0.7

This is a minor release. It patches a few border case bugs in the stepper preventing maps in geodetic coordinates to be used. It also add a CMakeLists.txt for building & installing the library with CMake.

Bug fixes

• Patch a bug in the stepper preventing maps in geodetic coordinates to be used.
• Patch an infinite loop when the stepper was hitting the data boundary.

Improvements

• Added a CMakelists.txt for building the TURTLE library with CMake.

TURTLE v0.6

This release extends the stepper. It allows to specify geometries with multiple topography layers, e.g. a soil below the ground, a water layer above, a canopy, etc.

Topography layers

• A new topography layer is created with the turtle_stepper_add_layer function.
• Data are added to the layer using the turtle_stepper_add_flat, turtle_stepper_add_map and turtle_stepper_add_stack functions, as previously. But, an offset can now be specified, e.g. 50 cm below the data elevation value.

A single data set can be used in several layers. The stepper automatically manages not duplicating the data sets, frame transforms, etc. Internally, a generic linked list object was added, in order to handle meta data, maps within a stack, etc.

Unit tests

Unit tests have been extended. In addition, they are now handled within the Check framework, using libcheck. A target was added to the Makefile that allows to install libcheck locally, if needed.

TURTLE v0.5

This release extends the stepper API. It embeds a simple stepping algorithm based on an optimistic heuristic. The main new features are:

• Stacks can now have an infinite size, by setting the size parameter to 0 or less at creation.
• A stack_load function was added in order to force loading all tiles of a stack.
• The stepper object can now perform basic steps based on an optimistic heuristic.
• An ECEF position getter was added to the stepper. It takes geodetic coordinates and height above ground as input. This is to ease the initialization of the stepping.
• The API has been cleaned. In particular the turtle_initialise and turtle_finalise functions have been removed.
• Unit testing and CI have been added.
• Some more bugs have been patched ...

TURTLE v0.4

This new release cleans and simplifies the TURTLE API. Its main features are:

• Unify maps and tiles as a single object
• Migrate ECEF routines to a separate name space and rename the turtle_datum object to turtle_stack.
• Add support for geoids as tabulated maps (add GRD format for EGM96).
• Replace the turtle_box object with a turtle_map_info structure, gathering all map meta data (except any projection).
• Clean the error stream and cross module functions.
• Provide a default error handler for library errors, with a hard exit.
• Package light dependencies with the source, i.e. JSMN and TinyDir.

Note that several API functions and objects have changed with this update.

TURTLE v0.3

• Patch quite some bugs.
• Add support for HGT format, e.g. SRTMGL data.
• Add a turtle_stepper object for optimized stepping through layered data sets.