FLOW -- FieLd Of View Visualizer
================================

FLOW is a field-of-view simulator of an instrument on-board
a spacecraft. This software is designed based on SPICE Toolkit
developed by NASA JPL.

See the following website for more details of SPICE toolkit:

http://naif.jpl.nasa.gov/naif/index.html

Overview
--------

FLOW is composed of two types of software:

    flow_se  ... Simulation engine
    flow_ig  ... Image generator
    flow_cov ... Coverage checker

flow_se reads a configuration file which contains the condition
of the observation and file paths such as SPICE kernels, shape
models, and textures. The result of simulation is written in a
XML file.

    conf_file ---> (flow_se) ---> simulation.xml

flow_ig reads the output of flow_se, and making an image using
shape models and textures.

    simulation.xml ----+
                       |
    texture -----------+---> (flow_ig) ---> image
                       |
    model -------------+

flow_cov reads a configuration file as well as flow_se.
The flow_cov shows the time coverage using spice kernels.

Features
--------

Generic features:

- SPICE-based simulation
- Old rendering technique (no OpenGL)
- Support of PNG, JPEG, and FITS
- Support of non-rectangle FOV shape
- Support of Push-bloom type observation
- Drawing planets, satellites with textures
- Drawing Stars (Hipparcos database)
- Drawing Polygon shape model(STL format or DSK Type2 format)
- Drawing planetary-rings (Jupiter, Saturn)
- Web Map Service (WMS) support for texture

FITS related features:
- World Coordinate System (WCS) information in FITS header
- RGB FITS support (FITS multiple extension, FITS 3D Cube)

Installation
------------
See the file INSTALL for generic compilation and installation
instructions.

FLOW requires the following libraries:

    CSPICE Toolkits for C
    libxml2 2.6.5 or later
    Lua 5.1 or 5.2

The following packages are optional, but making images, at least
one of cfitsio, libpng, jpeglib is required.
    
    CFITSIO 3.31 or later
    libpng 1.2.49 or later
    jpeglib 6b or later

If you connect to a server of Web Map Service (WMS) to obtain
planetary texture, libcurl package is required.

    libcurl 7.19 or later

