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`gama-local`

Program `gama-local`

is a simple command line tool for adjustment
of geodetic *free networks.* It is available for GNU Linux (the
main platform on which project GNU Gama is being developed), BSD or
Windows.

Program `gama-local`

reads input data in XML format (XML input data format for `gama-local`

) and prints adjustment results into
ASCII text file. If output file name is not given, adjustment results
in XML format are sent to the standard output device.
If development files for `Sqlite3`

(package `libsqlite3-dev`

) are
installed, `gama-local`

also supports reading
adjustment input data from `sqlite3`

database.
When run without arguments `gama-local [--help]`

prints a review of runtime options

Adjustment of local geodetic network version: 2.24 / GNU C/C++ 11.3 ************************************ https://www.gnu.org/software/gama/ Usage: gama-local [--input-xml] input.xml [options] gama-local [--input-xml] input.xml --sqlitedb sqlite.db --configuration name [options] gama-local --sqlitedb sqlite.db --configuration name [options] gama-local --sqlitedb sqlite.db --readonly-configuration name [options] Options: --algorithm gso | svd | cholesky | envelope --language en | ca | cz | du | es | fi | fr | hu | ru | ua | zh --encoding utf-8 | iso-8859-2 | iso-8859-2-flat | cp-1250 | cp-1251 --angular 400 | 360 --latitude <latitude> --ellipsoid <ellipsoid name> --text adjustment_results.txt --html adjustment_results.html --xml adjustment_results.xml --octave adjustment_results.m --svg network_configuration.svg --cov-band covariance matrix of adjusted parameters in XML output n = -1 for full covariance matrix (implicit value) n >= 0 covariances are computed only for bandwidth n --iterations maximum number of iterations allowed in the linearized least squares algorithm (implicit value is 5) --export updated input data based on adjustment results --verbose [yes | no] --version --help Report bugs to: <bug-gama@gnu.org> GNU gama home page: <https://www.gnu.org/software/gama/> General help using GNU software: <https://www.gnu.org/gethelp/> |

Program version is followed by information on
compiler used to build the program (apart from GNU `g++`

compiler other possibilities are Clang, Intel C++ compiler and
Visual C++, when build under Microsoft Windows).

Program `gama-local`

can read XML input from the standard input
if you put "-" (hyphen) after the option `--input-xml`

. This
option is special because it is optional (you can specify XML input
file name or "-" without it). Elective `--input-xml`

enables
backward compatibility with the usage of older versions.

Adjustment results (`--text`

, `--xml`

) and others can be
similarly redirected to standard output if instead of a file name is
used "-" string. If no output is given, XML adjustment format is
implicitly send to standard output.

Option `--algorithm`

enables to select numerical method for
solution of the adjustment.
Implicit algorithm is sparse matrix `envelope`

.
Another possibilities are
Cholesky decomposition of semidefinite matrix of normal
equations (`cholesky`

),
block matrix algorithm GSO by Frantisek Charamza based on
Gram-Schmidt orthogonalization (`gso`

) and
Singular Value Decomposition (`svd`

).
In the last two cases (`gso`

and `svd`

) project equations
are solved directly without forming *normal equations*.

Option `--language`

selects language used in output protocol. For
example, if run with option `--language cz`

, `gama-local`

prints output results in Czech languague using UTF-8
encoding. Implicit value is `en`

for output in English.

Option `--encoding`

enables to change inplicit UTF-8 output
encoding to iso-8859-2 (latin-2), iso-8859-2-flat (latin-2 without
diacritics), cp-1250 (MS-EE encoding) cp-12251 (Russian encoding).

Option `--angular`

selects angular units to be used in output.

Options `--latitude`

and/or `--ellipsoid`

are used when
observed vertical and/or zenith angles need to be transformed into the
projection plane. If none of these two options is explicitly used, no
corrections are added to horizontal and/or zenith angles. If only one
of these options is used, then implicit value for `--latitude`

is
45 degrees (50 gons) and implicit ellipsoid is WGS84.
Mathematical formulas for the corrections is given in the following
section.

Option `--octave`

is used to output simplified adjustment results
for GNU Octave, i.e. in
an .m file. The following information is give in the output
file

- general adjustment paramameters (number of unknowns, observetions etc.)
- list of fixed points’ ids (may be empty)
- adjustment points; ids
- adjustment indexes of unknouwns
- indexes of constrained coordinates (subset of adjustment indexes)
- approximate and adjusted coordinates (zero if not available)
- full covariance matrix of adjusted coordinates
- sparse design matrix, rhs and weights (Ax = b, P = inv(C_ll))
- and adjustment results in matrix format

In the case of free networks system of normal equations is augmented
with matrix of constrains. Adjustmment can be then computed
independetly in Octave and compared with results from Gama for unknown
coordinates. We suggest that for comaprision of Gama and Octave
results number of itereations is set to zero (`--iterations 0`

).

This Octave output is currently available only for algorithm
*envelope* (Gama version 2.10), also adjustment in Octave is not
supported for the special case of *one fixed point and one
constrained* (where normal equation cannot be directly augmented with
constraints because of different number of unknowns).

Option `--cov-band`

is used to reduce the number of computed
covariances (cofactors) in XML adjustment output. Implicitly full
matrix is written to XML output, which could degrade time efficiency
for the `envelope`

algorithm for sparse matrix solution. Explicit
option for full covariance matrix is `--cov-band -1`

, option
`--cov-band 0`

means that only a diagonal of covariance matrix is
written to XML output, `--cov-band 1`

results in computing the
main diagonal and first codiagonal etc. If higher rank is specified then
available, it is reduced do maximum possible value `dim-1`

.

Option `--iterations`

enables to set maximum number of
iterations allowed in the linearized least squares algorithm. After
the adjustment `gama-local`

computes differences between adjusted
observations computed from residuals and from adjusted coordinates. If
the positional difference is higher than 0.5mm, approximate
coordinates of adjusted points are updated and the whole adjustment is
repeated in a new iteration. Implicit number of iterations is 5.

1.3.1 Reductions of horizontal and zenith angles |

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