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112 changes: 104 additions & 8 deletions doc/source/api.md
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Expand Up @@ -11,21 +11,38 @@ documentation.
.. currentmodule:: xdem
```

## DEM

```{eval-rst}
.. minigallery:: xdem.DEM
:add-heading:
```

### Opening a DEM
## DEM

```{important}
A {class}`~xdem.DEM` inherits all raster methods and attributes from the {class}`~geoutils.Raster` object of GeoUtils.
Below, we only repeat the core attributes and methods of GeoUtils, see
[the Raster API in GeoUtils](https://geoutils.readthedocs.io/en/latest/api.html#raster) for the full list.
```

### Opening or saving a DEM

```{eval-rst}
.. autosummary::
:toctree: gen_modules/
DEM
DEM.info
DEM.save
```

### Plotting a DEM

```{eval-rst}
.. autosummary::
:toctree: gen_modules/
DEM
DEM.plot
```

### Create from an array
Expand All @@ -41,27 +58,40 @@ documentation.

### Unique attributes

```{note}
A {class}`~xdem.DEM` inherits four unique attributes from {class}`~geoutils.Raster`, see [the dedicated section of GeoUtils' API](https://geoutils.readthedocs.io/en/latest/api.html#unique-attributes).
#### Inherited from {class}`~geoutils.Raster`

```{eval-rst}
.. autosummary::
:toctree: gen_modules/
DEM.data
DEM.crs
DEM.transform
DEM.nodata
```

#### Specific to {class}`~xdem.DEM`

```{eval-rst}
.. autosummary::
:toctree: gen_modules/
DEM.vcrs
```

### Derived attributes
### Georeferencing

#### Inherited from {class}`~geoutils.Raster`

```{eval-rst}
.. autosummary::
:toctree: gen_modules/
DEM.ccrs
DEM.reproject
DEM.crop
```

### Vertical referencing
#### Vertical referencing for {class}`~xdem.DEM`

```{eval-rst}
.. autosummary::
Expand All @@ -71,6 +101,53 @@ A {class}`~xdem.DEM` inherits four unique attributes from {class}`~geoutils.Rast
DEM.to_vcrs
```

### Raster-vector interface

```{note}
See the full list of vector methods in [GeoUtils' documentation](https://geoutils.readthedocs.io/en/latest/api.html#vector).
```

```{eval-rst}
.. autosummary::
:toctree: gen_modules/
DEM.polygonize
DEM.proximity
```

### Coregistration

```{tip}
To build and pass your coregistration pipeline to {func}`~xdem.DEM.coregister_3d`, see the API of {ref}`api-geo-handle`.
```

```{eval-rst}
.. autosummary::
:toctree: gen_modules/
DEM.coregister_3d
```

### Terrain attributes

```{eval-rst}
.. autosummary::
:toctree: gen_modules/
DEM.slope
DEM.aspect
DEM.hillshade
DEM.curvature
DEM.profile_curvature
DEM.planform_curvature
DEM.maximum_curvature
DEM.topographic_position_index
DEM.terrain_ruggedness_index
DEM.roughness
DEM.rugosity
DEM.fractal_roughness
```

## dDEM

```{eval-rst}
Expand Down Expand Up @@ -113,6 +190,25 @@ A {class}`~xdem.DEM` inherits four unique attributes from {class}`~geoutils.Rast
xdem.coreg.BlockwiseCoreg
```

#### Fitting and applying transforms

```{eval-rst}
.. autosummary::
:toctree: gen_modules/
xdem.coreg.Coreg.fit
xdem.coreg.Coreg.apply
```

#### Other functionalities

```{eval-rst}
.. autosummary::
:toctree: gen_modules/
xdem.coreg.Coreg.residuals
```

### Affine coregistration methods


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8 changes: 8 additions & 0 deletions doc/source/coregistration.md
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Expand Up @@ -23,6 +23,14 @@ Those transformations include for instance:
- rotations, reflections,
- scalings.

## Quick use

Coregistrations are defined using either a single method or pipeline of {class}`~xdem.coreg.Coreg` methods, that are listed below.

Performing the coregistration on a pair of DEM is done either by using {func}`xdem.DEM.coregister_3d` from the DEM that will be aligned, or
by specifying the {func}`xdem.coreg.Coreg.fit` and {func}`xdem.coreg.Coreg.apply` steps, which allows array inputs and
to apply the same fitted transformation to several objects (e.g., horizontal shift of both a stereo DEM and its ortho-image).

## Introduction

Coregistration of a DEM is performed when it needs to be compared to a reference, but the DEM does not align with the reference perfectly.
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166 changes: 166 additions & 0 deletions doc/source/dem_class.md
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---
file_format: mystnb
jupytext:
formats: md:myst
text_representation:
extension: .md
format_name: myst
kernelspec:
display_name: xdem-env
language: python
name: xdem
---
(dem-class)=

# The digital elevation model ({class}`~xdem.DEM`)

Below, a summary of the {class}`~xdem.DEM` object and its methods.

(dem-obj-def)=

## Object definition and attributes

A {class}`~xdem.DEM` is a {class}`~geoutils.Raster` with an additional georeferenced vertical dimension stored in the attribute {attr}`~xdem.DEM.vcrs`.
It inherits the **four main attributes** of {class}`~geoutils.Raster` which are {attr}`~xdem.DEM.data`,
{attr}`~xdem.DEM.transform`, {attr}`~xdem.DEM.crs` and {attr}`~xdem.DEM.nodata`.

Many other useful raster attributes and methods are available through the {class}`~geoutils.Raster` object, such as
{attr}`~geoutils.Raster.bounds`, {attr}`~geoutils.Raster.res`, {func}`~xdem.DEM.reproject` and {func}`~xdem.DEM.crop` .

```{tip}
The complete list of {class}`~geoutils.Raster` attributes and methods can be found in [GeoUtils' API](https://geoutils.readthedocs.io/en/stable/api.html#raster) and more info on rasters on [GeoUtils' Raster documentation page](https://geoutils.readthedocs.io/en/stable/raster_class.html).
```

## Open and save

A {class}`~xdem.DEM` is opened by instantiating with either a {class}`str`, a {class}`pathlib.Path`, a {class}`rasterio.io.DatasetReader` or a
{class}`rasterio.io.MemoryFile`, as for a {class}`~geoutils.Raster`.


```{code-cell} ipython3
import xdem
# Instantiate a DEM from a filename on disk
filename_dem = xdem.examples.get_path("longyearbyen_ref_dem")
dem = xdem.DEM(filename_dem)
dem
```

Detailed information on the {class}`~xdem.DEM` is printed using {func}`~geoutils.Raster.info`, along with basic statistics using `stats=True`:

```{code-cell} ipython3
# Print details of raster
dem.info(stats=True)
```

```{important}
The {class}`~xdem.DEM` data array remains implicitly unloaded until {attr}`~xdem.DEM.data` is called. For instance, here, calling {class}`~xdem.DEM.info()` with `stats=True` automatically loads the array in-memory.
The georeferencing metadata ({attr}`~xdem.DEM.transform`, {attr}`~xdem.DEM.crs`, {attr}`~xdem.DEM.nodata`), however, is always loaded. This allows to pass it effortlessly to other objects requiring it for geospatial operations (reproject-match, rasterizing a vector, etc).
```

A {class}`~xdem.DEM` is saved to file by calling {func}`~xdem.DEM.save` with a {class}`str` or a {class}`pathlib.Path`.

```{code-cell} ipython3
# Save raster to disk
dem.save("mydem.tif")
```
```{code-cell} ipython3
:tags: [remove-cell]
import os
os.remove("mydem.tif")
```

## Plotting

Plotting a DEM is done using {func}`~xdem.DEM.plot`, and can be done alongside a vector file.

```{code-cell} ipython3
# Open a vector file of glacier outlines near the DEM
import geoutils as gu
fn_glacier_outlines = xdem.examples.get_path("longyearbyen_glacier_outlines")
vect_gla = gu.Vector(fn_glacier_outlines)
# Plot the DEM and the vector file
dem.plot(cmap="terrain", cbar_title="Elevation (m)")
vect_gla.plot(dem) # We pass the DEM as reference for the plot CRS/extent
```

## Vertical referencing

The vertical reference of a {class}`~xdem.DEM` is stored in {attr}`~xdem.DEM.vcrs`, and derived either from its
{attr}`~xdem.DEM.crs` (if 3D) or assessed from the DEM product name during instantiation.

```{code-cell} ipython3
# Check vertical CRS of dataset
dem.vcrs
```

In this case, the DEM has no defined vertical CRS, which is quite common. To set the vertical CRS manually,
use {class}`~xdem.DEM.set_vcrs`. Then, to transform into another vertical CRS, use {class}`~xdem.DEM.to_vcrs`.

```{code-cell} ipython3
# Define the vertical CRS as the 3D ellipsoid of the 2D CRS
dem.set_vcrs("Ellipsoid")
# Transform to the EGM96 geoid
dem.to_vcrs("EGM96")
```

```{note}
For more details on vertical referencing, see the {ref}`vertical-ref` page.
```

## Terrain attributes

A wide range of terrain attributes can be derived from a {class}`~xdem.DEM`, with several methods and options available,
by calling the function corresponding to the attribute name such as {func}`~xdem.DEM.slope`.

```{code-cell} ipython3
# Derive slope using the Zevenberg and Thorne (1987) method
slope = dem.slope(method="ZevenbergThorne")
slope.plot(cmap="Reds", cbar_title="Slope (degrees)")
```

```{note}
For the full list of terrain attributes, see the {ref}`terrain-attributes` page.
```

## Coregistration

3D coregistration is performed with {func}`~xdem.DEM.coregister_3d`, which aligns the
{class}`~xdem.DEM` to another DEM using a pipeline defined with a {class}`~xdem.coreg.Coreg`
object (defaults to horizontal and vertical shifts).

```{code-cell} ipython3
# Another DEM to-be-aligned to the first one
filename_tba = xdem.examples.get_path("longyearbyen_tba_dem")
dem_tba = xdem.DEM(filename_tba)
# Coregister (horizontal and vertical shifts)
dem_tba_coreg = dem_tba.coregister_3d(dem)
# Plot the elevation change of the DEM due to coregistration
dh_tba = dem_tba - dem_tba_coreg.reproject(dem_tba)
dh_tba.plot(cmap="Spectral", cbar_title="Elevation change due to coreg (m)")
```

```{note}
For more details on building coregistration pipelines and accessing metadata, see the {ref}`coregistration` page.
```

## Uncertainty analysis

Estimation of DEM-related uncertainty can be performed with {func}`~xdem.DEM.estimate_uncertainty`, which estimates both
**an error map** considering variable per-pixel errors and **the spatial correlation of errors**. The workflow relies
on an independent elevation data object that is **assumed to have either much finer or similar precision**, and uses
stable terrain as a proxy.

```{code-cell} ipython3
# Estimate elevation uncertainty assuming both DEMs have similar precision
sig_dem, rho_sig = dem.estimate_uncertainty(dem_tba_coreg, precision_of_other="same")
# The error map variability is estimated from slope and curvature by default
sig_dem.plot(cmap="Purples", cbar_title=r"Error in elevation (1$\sigma$, m)")
# The spatial correlation function represents how much errors are correlated at a certain distance
rho_sig(1000) # Correlation at 1 km
12 changes: 12 additions & 0 deletions doc/source/elevation_objects.md
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(elevation-objects)=
# Elevation data objects

Elevation data objects of xDEM inherit their characteristics from raster and vector objects of
our sister-package [GeoUtils](https://geoutils.readthedocs.io/en/stable/).

```{toctree}
:maxdepth: 2
dem_class
elevation_point_cloud
```
17 changes: 17 additions & 0 deletions doc/source/elevation_point_cloud.md
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---
file_format: mystnb
jupytext:
formats: md:myst
text_representation:
extension: .md
format_name: myst
kernelspec:
display_name: xdem-env
language: python
name: xdem
---
(elevation-point-cloud)=

# The elevation point cloud ({class}`~xdem.EPC`)

In construction, planned for 2024.
3 changes: 2 additions & 1 deletion doc/source/index.md
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Expand Up @@ -98,12 +98,13 @@ intro_accuracy_precision
:caption: Features
:maxdepth: 2
elevation_objects
vertical_ref
terrain
coregistration
biascorr
comparison
spatialstats
uncertainty
```

```{toctree}
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