TerraGear Documentation: Difference between revisions

From FlightGear wiki
Jump to navigation Jump to search
No edit summary
Line 34: Line 34:
This is where hgt-chop will generated the elevation directory tree described above.
This is where hgt-chop will generated the elevation directory tree described above.


== hgtfit ==
= hgtfit =


== ogr-decode ==
= ogr-decode =


== genapts / genapts850 ==
= genapts / genapts850 =


== fgfs-construct ==
= fgfs-construct =


== Related content ==
= Related content =
* [[Using Terragear]]
* [[Using Terragear]]
* [[TerraGear CORINE]]
* [[TerraGear CORINE]]

Revision as of 02:42, 6 June 2012

Introduction

There has been a lot of questions relating to scenery generation tools. This page is an attempt to document each of the tools I use. I will also document the design, and what each tool is actually doing. My hope is to attract more developers to work on the tools to make it easier to create better scenery for FlightGear.

hgtchop

hgtchop is responsible for cropping height data files into SimGear buckets (or tiles). Most height data format is published in fairly large data files that cover 1 square degree.

command options

hgtchop <resolution> <hgt_file> <work_dir>

description

When later tools need to query elevation data, they do so expecting the data to be located in a standard Simgear folder structure as follows:

10 deg x 10 deg folder

1 degree by 1 degree folder
bucket number.xxx


hgtchop will create this directory structure in the work folder, and create sgbucket.arr.gz files within.

resolution

Each file created contains ALL of the data points for the simgear tile. For SRTM-1 data, the grid is TODO For SRTM-3 data, the grid is TODO. The resolution parameter tells hgtcop the distance between sampled points.

hgt_file

The source file. Usually, the source files are 1 degree by 1 degree, and has enough data to create 32 simgear buckets.

work_dir

This is where hgt-chop will generated the elevation directory tree described above.

hgtfit

ogr-decode

genapts / genapts850

fgfs-construct

Related content