Commit 8a3af7c0 authored by Daniel McInerney's avatar Daniel McInerney
Browse files

DOC: suggested edits to the documentation

parent d6be4afb
......@@ -3,11 +3,11 @@ RST docs for Orfeo Toolbox CookBook
Introduction
============
This is a replacement of old OTB Cookbook which was written in Latex. This version is completely deviate from existing Latex format to reStructured format (rst).
This is a replacement of the old OTB Cookbook which was written in LaTeX. This version has deviated completely from the existing LaTeX format to reStructured format (rst).
Converting existing latex to rst is not that straightforward. All rst files for OTB applications are generated using python script otbGenerateWrappersRstDoc.py.
For others in recipes, we used a tool called pandoc to get an initial rst and then edited out errors manually. You do not have to generate them again.
The old Cookbook in otb-documents is deprecated.
Converting existing LaTeX to rst is not that straightforward. All rst files for OTB applications are generated using the Python script otbGenerateWrappersRstDoc.py.
For others files in the Recipes, we used a tool called pandoc to get an initial rst and then manually edit and remove the errors. You do not have to generate them again.
The old Cookbook in otb-documents is now deprecated.
Requirements
============
......
......@@ -8,7 +8,7 @@ Environment variables that affect Orfeo ToolBox
The following environment variables are parsed by Orfeo ToolBox. Note
that they only affect default values, and that settings in extended
filenames, applications, monteverdi or custom C++ code might override
filenames, applications, Monteverdi or custom C++ code might override
those values.
* ``OTB_DEM_DIRECTORY``: Default directory were DEM tiles are
......@@ -26,29 +26,29 @@ those values.
default level is ``INFO``.
In addition to OTB specific environment variables, the following
environment variable are parsed by third party libraries and also
environment variables are parsed by third party libraries and also
affect how OTB works:
* ``GDAL_CACHEMAX``: Gdal has an internal cache mechanism to avoid reading or decoding again image chunks. This environnement variable controls how much memory Gdal can use for caching. By default, Gdal can use up to 5 percents of available RAM on system, which may be a lot. Moreover, caching is only needed if the processing chain is likely to request the same chunk several times, which is not likely to happen for a standard pixel based OTB pipeline. Setting a lower value allows to allocate more memory to OTB itself (using applications ``-ram`` parameter or ``OTB_MAX_RAM_HINT`` environment variable). If value is small (less than 100 000, it is assumed to be in megabytes, otherwise, it is assumed to be in bytes.
* ``GDAL_NUM_THREADS``: Gdal can take advantage of multi-threading to decode some formats. This variable controls the number of threads Gdal is allowed to use.
* ``OPJ_NUM_THREADS``: OpenJpeg can take advantage of mutli-threading when decoding images. This variable controls the number of threads OpenJpeg is allowed to use.
* ``ITK_GLOBAL_DEFAULT_NUMBER_OF_THREADS``: This variable allows to control the number of threads used by ITK for processing.
* ``GDAL_CACHEMAX``: GDAL has an internal cache mechanism to avoid reading or decoding again image chunks. This environment variable controls the amount of memory that GDAL can use for caching. By default, GDAL can use up to 5 percent of the system's available RAM, which may be a lot. In addition, caching is only needed if the processing chain is likely to request the same chunk several times, which is unlikely to happen for a standard pixel based OTB pipeline. Setting a lower value facilitates the allocation of more memory to OTB itself (using applications ``-ram`` parameter or ``OTB_MAX_RAM_HINT`` environment variable). If the value is small, i.e. less than 100 000, it is assumed to be in megabytes, otherwise, it is assumed to be in bytes.
* ``GDAL_NUM_THREADS``: GDAL can take advantage of multi-threading to decode some formats. This variable controls the number of threads GDAL is allowed to use.
* ``OPJ_NUM_THREADS``: OpenJpeg can take advantage of multi-threading when decoding images. This variable controls the number of threads OpenJpeg is allowed to use.
* ``ITK_GLOBAL_DEFAULT_NUMBER_OF_THREADS``: This variable controls the number of threads used by ITK for processing.
.. _extended-filenames:
Extended filenames
------------------
Extended filenames is an interesting feature of OTB. With it, you can control
several aspects of the beahvior of the OTB in the OTB-Applications or in our
own C++ applications. Historically this feature has been desingn to solve
an issue with how to handle geo-referencing information.
Extended filenames are an interesting feature of OTB. With them, it is possible to control
several aspects of the behavior of OTB in the OTB-Applications or in our
own C++ applications. Historically this feature was designed to facilitate
how geo-referencing information was handled.
Indeed, there are multiple ways to define geo-referencing information. For
instance, one can use a geographic transform, a cartographic projection,
or a sensor model with RPC coefficients. A single image may contain
several of these elements, such as in the “ortho-ready” products: this
is a type of product still in sensor geometry (the sensor model is
is a type of product that is still in sensor geometry (the sensor model is
supplied with the image) but it also contains an approximative
geographic transform that can be used to have a quick estimate of the
image localisation. For instance, your product may contain a “.TIF” file
......@@ -56,18 +56,18 @@ for the image, along with a “.RPB” file that contains the sensor model
coefficients and an “.IMD” file that contains a cartographic projection.
This case leads to the following question: which geo-referencing
element should be used when opening this image in OTB. In
fact, it depends on the users need. For an orthorectification
element should be used when the image is opened in OTB. In
fact, it depends on the user's requirements. For an orthorectification
application, the sensor model must be used. In order to specify which
information should be skipped, a syntax of extended filenames has been
developed for both reading and writing.
Since the development of this feature we have extend this mechanism for
other aspaects: like band or overview selection in reader part or support
create option of gdal in writer part.The reader and writer extended filename
Since the development of this feature, we have extended this mechanism for
other aspects. This includes band or overview selection in reader part or support
create option of GDAL in writer part. The reader and writer extended filename
support is based on the same syntax, only the options are different.
To benefit from the extended file name mechanism, the following syntax
is to be used:
To benefit from the extended filename mechanism, the following syntax
should be used:
::
......@@ -82,7 +82,7 @@ Reader options
&geom=<path/filename.geom>
- Contains the file name of a valid geom file
- Contains the filename of a valid geom file
- Use the content of the specified geom file instead of
image-embedded geometric information
......@@ -117,20 +117,20 @@ Reader options
- Select a subset of bands from the input image
- The syntax is inspired by Python indexing syntax with
bands=r1,r2,r3,...,rn where each ri is a band range that can be :
- The syntax is inspired by the Python indexing syntax with
bands=r1,r2,r3,...,rn where each ri is a band range that can be:
- a single index (1-based) :
- :code:`2` means 2nd band
- :code:`2` means the second band
- :code:`-1` means last band
- or a range of bands :
- :code:`3:` means 3rd band until the last one
- :code:`3:` means from the third band until the last band
- :code:`:-2` means the first bands until the second to last
- :code:`:-2` means the first band up until the penultimate band
- :code:`2:4` means bands 2,3 and 4
......@@ -158,7 +158,7 @@ Reader options
&skipgeom=<(bool)true>
- Skip geometric information
- Skip the geometric information
- Clears the keyword list
......@@ -204,9 +204,9 @@ Writer options
&gdal:co:<GDALKEY>=<VALUE>
- To specify a gdal creation option
- To specify a GDAL creation option
- For gdal creation option information, see dedicated gdal documentation for each driver. For example, you can find `here <http://www.gdal.org/frmt_gtiff.html>`_ the information about the GeoTiff create options
- For GDAL creation option information, see the dedicated GDAL documentation for each driver. For example, you can find `here <http://www.gdal.org/frmt_gtiff.html>`_ the information about the GeoTiff create options
- None by default
......@@ -241,7 +241,7 @@ Writer options
&streaming:sizemode=<VALUE>
- Allows to choose how the size of the streaming pieces is computed
- Provides the option to choose how the size of the streaming pieces is computed
- Available values are:
......@@ -270,8 +270,8 @@ Writer options
- if sizemode=nbsplits: number of requested splits for streaming
- If not provided, the default value is set to 0 and result in
different behaviour depending on sizemode (if set to height or
- If not provided, the default value is set to 0 and results in
different behaviours depending on sizemode (if set to height or
nbsplits, streaming is deactivated, if set to auto, value is
fetched from configuration or cmake configuration file)
......@@ -338,25 +338,22 @@ The available syntax for boolean options are:
&nodata=(double) value / [int:double, int:double ...]
- This options allows one to set specific nodata values for all or selected bands.
- This options allows one to set specific nodata values for all or selected bands. The nodata values can be set in two ways: either using a simple scalar value or band,value pairs. OTB will select either one of them depending on the type of nodata value string specified.
There are two ways of setting nodata values. simple scalar values of band,value pair.
OTB will select either one of them depending on type of nodata value string
- If value is scalar (without bandindex), it will be applied only to first band of image.
- If the value is scalar (without bandindex), it will be applied only to the first band of the image.
- If value is given as "bandindex:value" pair separated by a ":" then
nodata value is applied to only those selected band.
- If the value is given as "bandindex:value" pair separated by a ":" then
the nodata value is applied to only those selected band.
- By default OTB will not alter any existing nodata value.
- By default OTB will not alter any existing nodata value.
OGR DataSource options
^^^^^^^^^^^^^^^^^^^^^^^
We extended this process to OGR DataSource. There are three different type of
option : open, creation and layer creation. Those options come from the GDAL
API. In order to use them one just need to specify to which of this family
the option one want to use is from.
We extended this process to OGR DataSource. There are three different types of
options: open, creation and layer creation, which come directly from the GDAL
API. In order to use them, one just needs to specify the family that the option is
from.
For open option :
......@@ -383,7 +380,7 @@ For layer creation option :
Examples
^^^^^^^^^^^^^^
You can find below some examples:
Some examples are provided below:
- Write a file with blockSize equal to 256 and with DEFLATE compression
......
......@@ -30,10 +30,10 @@ What's in OTB?
- Geospatial analysis.
For a full list of applications see the :ref:`apprefdoc`.
For a full list of applications see the chapter :ref:`apprefdoc`.
For an introduction to the C++ API see the
`Software Guide <https://www.orfeo-toolbox.org/SoftwareGuide/>`_.
And for exhaustive descrpition of the C++ API see the
And for an exhaustive description of the C++ API see the
`Doxygen <https://www.orfeo-toolbox.org/doxygen/>`_.
What is ORFEO?
......
......@@ -20,7 +20,7 @@ entry points. While the framework can be extended, the Orfeo ToolBox ships with
ergonomic parameters setting, display of documentation, and progress
reporting,
- A SWIG interface, which means that any application can be loaded
- A SWIG interface, which means that any application can be loaded,
set-up and executed into a high-level language such as Python or Java
for instance.
......@@ -28,20 +28,20 @@ entry points. While the framework can be extended, the Orfeo ToolBox ships with
the SWIG/Python interface is available with seamless integration within
QGIS.
The complete list of applications is described in the :ref:`apprefdoc`.
The complete list of applications is described in the Chapter :ref:`apprefdoc`.
All standard applications share the same implementation and expose
automatically generated interfaces.
Thus, the command-line interface is prefixed by ``otbcli_``, while the Qt interface is prefixed by
``otbgui_``. For instance, calling ``otbcli_Convert`` will launch the
All standard applications share the same implementation and automatically expose
generated interfaces.
However they are accessed in a slightly different way: the command-line interface is prefixed by ``otbcli_``, while the Qt interface is prefixed by
``otbgui_``. For cwinstance, calling ``otbcli_Convert`` will launch the
command-line interface of the Convert application, while
``otbgui_Convert`` will launch its GUI.
``otbgui_Convert`` will launch the GUI.
Command-line launcher
---------------------
The command-line application launcher loads an application
plugin, to set its parameters, and execute it using the command line.
plugin, allows for its parameters to be set, and can then be executed from the command line.
Launching the ``otbApplicationLauncherCommandLine`` without any arguments provided,
results in the following help to be displayed:
......@@ -52,23 +52,23 @@ results in the following help to be displayed:
The ``module_name`` parameter corresponds to the application name. The
``[MODULEPATH]`` argument is optional and allows the path to the shared library
(or plugin) correpsonding to the ``module_name`` to be passed to the launcher.
(or plugin) corresponding to the ``module_name`` to be passed to the launcher.
It is also possible to set this path with the environment variable
``OTB_APPLICATION_PATH``, making the ``[MODULEPATH]`` optional. This
variable is checked by default when no ``[MODULEPATH]`` argument is
given. When using multiple paths in ``OTB_APPLICATION_PATH``, one must
make sure to use the standard path separator of the target system, which
ensure that the standard path separator of the target system is used, which
is ``:`` on Unix and ``;`` on Windows.
An error in the application name (i.e. in parameter ``module_name``)
will make the ``otbApplicationLauncherCommandLine`` lists the name of
will make the ``otbApplicationLauncherCommandLine`` list the name of
all applications found in the available path (either ``[MODULEPATH]``
and/or ``OTB_APPLICATION_PATH``).
To ease the use of the applications, and try avoiding extensive
environment customization, ready-to-use scripts are provided by the OTB
installation to launch each application, and takes care of adding the
To ease the use of the applications, and to avoid extensive
environment customizations; ready-to-use scripts are provided by the OTB
installation to launch each application. They take care of adding the
standard application installation path to the ``OTB_APPLICATION_PATH``
environment variable.
......@@ -79,7 +79,7 @@ application with the script called ``otbcli_Orthorectification``.
Launching an application without parameters, or with incomplete parameters, will cause the
launcher to display a summary of the parameters. This summary will display the minimum set
of parameters that are required to execute the application. Here is an
example with the OrthoRectification application:
example based on the OrthoRectification application:
::
......@@ -125,11 +125,11 @@ example with the OrthoRectification application:
For a detailed description of the application behaviour and parameters,
please check the application reference documentation presented
chapter [chap:apprefdoc], page  or follow the ``DOCUMENTATION``
hyperlink provided in ``otbApplicationLauncherCommandLine`` output.
in chapter :ref:`apprefdoc`  or follow the ``DOCUMENTATION``
hyperlink provided in the output of ``otbApplicationLauncherCommandLine``.
Parameters are passed to the application using the parameter key (which
might include one or several ``.`` character), prefixed by a ``-``.
Command-line examples are provided in chapter [chap:apprefdoc], page.
Command-line examples are provided in the chapter :ref:`apprefdoc`.
Graphical launcher
------------------
......@@ -193,7 +193,7 @@ environment variable ``PYTHONPATH`` to include this directory so that the module
becomes available from Python.
On Windows, you can install the ``otb-python`` package, and the module
will be available from an OSGeo4W shell automatically.
will be automatically available from an OSGeo4W shell.
As for the command line and GUI launchers, the path to the application
modules needs to be properly set with the ``OTB_APPLICATION_PATH``
......@@ -355,7 +355,7 @@ Here is an example of MPI call on a cluster::
One can see that the registration and pan-sharpening of the
panchromatic and multi-spectral bands of a Pleiades image has been split
among 560 cpus and only took 56 seconds.
between 560 CPUs and only took 56 seconds to complete.
Note that this MPI parallel invocation of applications is only
available for command-line calls to OTB applications, and only for
......
......@@ -20,6 +20,8 @@ A simple example is given below:
As we can see, the new band math filter works with the class
otb::VectorImage.
.. _syntax:
Syntax: first elements
----------------------
......@@ -134,8 +136,7 @@ or in more simple terms (and only if im2 contains two components):
.. math:: im2* \{1,2\}'
Concerning division, this operation is not originally defined between
two vectors (see next section “New operators and functions”
-[ssec:operators]-).
two vectors (see next section :ref:`operators`).
Now, let’s go back to the first formula: this one specifies the addition
of two images band to band. With muParserX lib, we can now define such
......@@ -170,6 +171,8 @@ Fundamentally, a neighbourhood is represented as a matrix inside the
muParserX framework; so the remark about mathematically well-defined
formulas still stands.
.. _operators:
New operators and functions
---------------------------
......@@ -205,7 +208,7 @@ ones. For instance:
.. math:: im1 ~ mlt ~ 2.0
Note that the operator ’\*’ could have been used instead of ’pw’ one.
But ’pw’ is a little bit more permisive, and can tolerate a
But ’pw’ is a little bit more permissive, and can tolerate a
one-dimensional vector as the right operand.
**Operators pow and pw** The first operator allows the definition of an
......@@ -267,20 +270,20 @@ takes two inputs). For instance:
.. math:: corr(im1b1N3x3,im1b2N3x3)
**Function maj** This function allows to compute the most represented
**Function maj** This function computes the most represented
element within a vector or a matrix (the function can take as many
inputs as needed; one maj element value is computed per input). For
instance:
.. math:: maj(im1b1N3x3,im1b2N3x3)
**Function vmin and vmax** These functions allow to compute the min or
**Function vmin and vmax** These functions calculate the min or
max value of a given vector or neighborhood (only one input). For
instance:
.. math:: (vmax(im3b1N3x5)+vmin(im3b1N3x5)) ~ div ~ \{2.0\}
**Function cat** This function allows to concatenate the results of
**Function cat** This function concatenates the results of
several expressions into a multidimensional vector, whatever their
respective dimensions (the function can take as many inputs as needed).
For instance:
......@@ -293,8 +296,7 @@ application will call the function ’cat’ automatically. For instance:
.. math:: filter->SetExpression("im3b1 ; vmin(im3b1N3x5) ; median(im3b1N3x5) ; vmax(im3b1N3x5)");
Please, also refer to the next section “Application Programming
Interface” ([ssec:API]).
Please, also refer to the next section :ref:`API`.
**Function ndvi** This function implements the classical normalized
difference vegetation index; it takes two inputs. For instance:
......@@ -302,7 +304,7 @@ difference vegetation index; it takes two inputs. For instance:
.. math:: ndvi(im1b1,im1b4)
First argument is related to the visible red band, and the second one to
the near-infrareds band.
the near-infrared band.
The table below summarises the different functions and operators.
......@@ -366,6 +368,8 @@ Functions and operators summary:
[variables]
.. _API:
Application Programming Interface (API)
---------------------------------------
......@@ -381,7 +385,7 @@ of the new band math filter.
/** Return a pointer on the nth filter input */
ImageType * GetNthInput(unsigned int idx);
Refer to the section “Syntax: first elements” ([ssec:syntax]) where the
Refer to the section :ref:`syntax`, where the
two first functions have already been commented. The function
GetNthInput is quite clear to understand.
......@@ -394,13 +398,13 @@ Each time the function SetExpression is called, a new expression is
pushed inside the filter. **There are as many outputs as there are
expressions. The dimensions of the outputs (number of bands) are totally
dependent on the dimensions of the related expressions (see also last
remark of the section “Syntax: first element” -[ssec:syntax]-).** Thus,
remark of the section :ref:`syntax`).** Thus,
the filter always performs a pre-evaluation of each expression, in order
to guess how to allocate the outputs.
The concatenation of the results of many expressions (whose results can
have different dimensions) into one unique output is possible. For that
puropose, semi-colons (“;”) are used as separating characters. For
purpose, semi-colons (“;”) are used as separating characters. For
instance:
.. math:: filter->SetExpression("im1 + im2 ; im1b1*im2b1");
......@@ -494,7 +498,7 @@ expr. For instance:
/** Export constants and expressions to a given filename */
void ExportContext(const std::string& filename);
This function allows the user to export a txt file that saves its
This function allows the user to export a text file that saves its
favorite constant or expression definitions. Such a file will be
reusable by the ImportContext function (see above).
......
......@@ -70,7 +70,7 @@ input image to the default value for DEM (which is -32768):
The third mode “apply” can be useful if you apply a formula to the
entire image. This will likely change the values of pixels flagged as
no-data, but the no-data value in the image metadata doesn’t change. If
no-data, but the no-data value in the image metadata does not change. If
you want to fix all no-data pixels to their original value, you can
extract the mask of the original image and apply it on the output image.
For instance:
......@@ -91,8 +91,8 @@ For instance:
-mode.apply.mask mask.tif
You can also use this “apply” mode with an additional parameter
“mode.apply.ndval”. This parameter allow to set the output nodata value
applying according to your input mask.
“mode.apply.ndval”. This parameter sets the output nodata value
of the input mask.
Segmentation
------------
......@@ -274,7 +274,7 @@ all the previous steps:
Most of the settings from the previous applications are also exposed in this
composite application. The range and spatial radius used for the segmentation
step are half the values used for Mean-Shift smooting, which are obtained from
step are half the values used for Mean-Shift smoothing, which are obtained from
LargeScaleMeanShift parameters. There are two output modes: vector (default)
and raster. When the raster output is chosen, last step (vectorization) is
skipped.
......@@ -295,8 +295,8 @@ Dempster Shafer based Classifier Fusion
This framework is dedicated to perform cartographic validation starting
from the result of a detection (for example a road extraction), enhance
the results fiability by using a classifier fusion algorithm. Using a
set of descriptor, the processing chain validates or invalidates the
the results viability by using a classifier fusion algorithm. Using a
set of descriptors, the processing chain validates or invalidates the
input geometrical features.
Fuzzy Model (requisite)
......@@ -341,7 +341,7 @@ for each studied polyline, the chosen descriptors. In this context, the
*ComputePolylineFeatureFromImage* application can be used for a large
range of descriptors. It has the following inputs:
- ``-in`` an image (of the sudied scene) corresponding to the chosen
- ``-in`` an image (of the studied scene) corresponding to the chosen
descriptor (NDVI, building Mask…)
- ``-vd`` a vector data containing polyline of interest
......@@ -394,7 +394,7 @@ Second Step: Feature Validation
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The final application (*VectorDataDSValidation* ) will validate or
unvalidate the studied samples using `the Dempster-Shafer
invalidate the studied samples using `the Dempster-Shafer
theory <http://en.wikipedia.org/wiki/Dempster%E2%80%93Shafer_theory>`_
. Its inputs are:
......
......@@ -10,7 +10,7 @@ Optical radiometric calibration
In remote sensing imagery, pixel values are referred to as Digital
Numbers (DN) and they cannot be physically interpreted or compared. They are
influenced by various factors such as the amount of light flowing through
the sensor, the gain of the detectors and the analogic to numeric
the sensor, the gain of the detectors and the analogue to digital
converter.
Depending on the season, the light and atmospheric conditions, the
......@@ -63,7 +63,7 @@ sensors are:
- Formosat
The *OpticalCalibration* application allows to perform optical
The *OpticalCalibration* application performs optical
calibration. The mandatory parameters are the input and output images.
All other parameters are optional. By default the level of calibration
is set to TOA (Top Of Atmosphere). The output images are expressed in
......@@ -128,7 +128,7 @@ Using either **OTB Applications** or modules from **Monteverdi** , it is
possible to perform both steps in a row, or step-by-step fusion, as
described in the above sections.
The *BundleToPerfectSensor* application allows to perform both steps in
The *BundleToPerfectSensor* application performs both steps in
a row. Seamless sensor modelling is used to perform zooming and
registration of the multi-spectral image on the panchromatic image. In
the case of a Pléiades bundle, a different approach is used: an affine
......@@ -157,15 +157,15 @@ application:
There are also optional parameters that can be useful for this tool:
- The ``-elev`` option allows to specify the elevation, either with a
DEM formatted for OTB (``-elev.dem`` option, see section [ssec:dem])
- The ``-elev`` option specifies the elevation, either with a
DEM formatted for OTB (``-elev.dem`` option, see section :ref:`dem`)
or with an average elevation (``-elev.default`` option). Since
registration and zooming of the multi-spectral image is performed
using sensor-models, it may happen that the registration is not
perfect in case of landscape with high elevation variation. Using a
DEM in this case allows to get better registration.
perfect in case of a landscape with a large variation in elevation. In this
case a DEM will allow for a better registration to be achieved.
- The ``-lmSpacing`` option allows to specify the step of the
- The ``-lmSpacing`` option specifies the step of the
registration grid between the multi-spectral image and panchromatic
image. This is expressed in amount of panchromatic pixels. A lower
value gives a more precise registration but implies more computation
......@@ -173,15 +173,15 @@ There are also optional parameters that can be useful for this tool:
Default value is 10 pixels, which gives sufficient precision in most
of the cases.
- The ``-mode`` option allows to select the registration mode for the
- The ``-mode`` option selects the registration mode for the
multi-spectral image. The ``default`` mode uses the sensor model of
each image to create a generic MS to Pan transform. The ``phr``
mode uses a simple affine transform (which doesnt need an elevation
mode uses a simple affine transform (which does not need an elevation
source nor a registration grid).
Pan-sharpening is a quite heavy processing requiring a lot of system
resource. The ``-ram`` option allows you to limit the amount of memory
available for the computation, and to avoid overloading your computer.
Pan-sharpening is a process that requires a lot of system
resources. The ``-ram`` option allows you to limit the amount of memory
available for the computation, and also avoids overloading your computer.
Increasing the available amount of RAM may also result in better
computation time, seems it optimises the use of the system resources.
Default value is 256 Mb.
......@@ -194,7 +194,7 @@ Figure 5: Pan-sharpened image using Orfeo ToolBox.
Please also note that since registration and zooming of the
multi-spectral image with the panchromatic image relies on sensor
modelling, this tool will work only for images whose sensor models is
available in **Orfeo ToolBox** (see :ref:`section3` for a detailed
available in **Orfeo ToolBox** (see Section :ref:`section3` for a detailed
list). It will also work with ortho-ready products in cartographic
projection.
......@@ -204,17 +204,17 @@ Digital Elevation Model management
----------------------------------
A Digital Elevation Model (DEM) is a georeferenced image (or collection
of images) where each pixel corresponds to a local elevation. DEM are
of images) where each pixel corresponds to a local elevation. DEMs are
useful for tasks involving sensor to ground and ground to sensor
coordinate transforms, like during ortho-rectification (see :ref:`section3`). These transforms need to find the intersection
coordinate transformations, for example, ortho-rectification (see Section :ref:`section3`). These transforms need to find the intersection
between the line of sight of the sensor and the Earth geoid. If a simple
spheroid is used as the Earth model, potentially high localisation
errors can be made in areas where elevation is high or perturbed. Of
course, DEM accuracy and resolution have a great impact on the precision
of these transformations.
Two main available DEM, free of charges, and with worldwide cover, are
both delivered as 1 degree by 1 degree tiles:
The two principal DEMs that are available free of charges, and with worldwide cover, are
both delivered as 1 degree by 1 degree tiles. They are:
- `The Shuttle Radar topographic Mission
(SRTM) <http://www2.jpl.nasa.gov/srtm/>`_ is a DEM with a resolution of 90 metres,
......@@ -232,7 +232,7 @@ are supposed to be located within a single directory. General elevation
support is also supported from GeoTIFF files.
Whenever an application or **Monteverdi** module requires a DEM, the
option **elev.dem** allows set the DEM directory. This directory must
option **elev.dem** sets the DEM directory. This directory must
contain the DEM tiles, either in DTED or SRTM format or as a GeoTIFF.
Subdirectories are not supported.
......@@ -244,7 +244,7 @@ the Earth.
We provide one geoid in the `OTB-Data <https://gitlab.orfeo-toolbox.org/orfeotoolbox/otb-data/tree/master/Input/DEM>`_ repository.
In all applications, the option **elev.geoid** allows to manage the path
In all applications, the option **elev.geoid** manages the path