Starting with ArcGis Pro: create your own source of elevations ( 2)

The
difference from the usual modus operandi is that when
you
click
the command, no new window opens.
The tool content opens geoprocessor window, and
it
will
stay displayed as long as you do
not decide otherwise by performing an
operation
with the geoprocessor.  

On top of the window, you can find two available
tabs for the tool : Parameters and Environments ,
which work as usual
.



Once the features are filled in, you can run
the
tool by clicking Run, located at the right bottom of the geoprocessor
window.
The
result ( terre_mer ) is added to the current view.

Now we will create a new “Zone”
field that we are going to give information to ” land
” or ” sea “. And we will benefit
by looking how the work is performed on the attribute table in
ArcGis Pro.

As in ArcMap, you open
the attribute table by right clicking on the layer
in
the legend window and selecting “Attribute
table”.
A
new window opens at the centre below the
View window.

To
create a new
field, you will use the first button on
the table button bar.
When
you
click
on the button, the parameterss for the definition of the new field appear
in
the geoprocessor window. In fact , in ArcGis Pro, all
the “flying” windows of ArcMap are now
brought
back to the geoprocessor window .
Once
the field is defined , as usually , by clicking
on the field name in the attribute table , you get
the
“Calculate field” option . The features will
, again, open in the geoprocessor window.
 

We fill all records with
“earth” and select the polygon
corresponding
to the sea and run the calculation again with ” sea ” as
value
. As in ArcMap, the field
calculator works only on the recordings
selected
, if any.

Generate
DTM for the
marine
section

To generate the marine DEM ,
we will add the
isobaths
layer ( corrected from hydro zero as indicated in
the
article 3D – Functional surfaces –
Specific case
 of the littoral ( earth –sea interface ) )
  

In
order to create the DTM we will use the command Topo to 3D
Analyst Raster.
In
the geoprocessor window, click Toolboxes and search the command.

In the
geoprocessor window, click Environments. This will
let you define the output extent equal to
the extent of the Emprise layer .

Also, we define the output size, in our
example
75m since it is the cell size of the terrestrial raster .

We execute the command and obtain the following DEM :
 

Before continuing the creation of the land-sea DEM ,
which we will see in the next article, we will
stop
for a moment to see what we just did but
this
-ci
time in 3D.

3D view with the generated DEM

Click the Scene tab. If you had not already done
so, remove the Topographic layer.

You get an empty
window .
If
you load the image Aerial
in
the 3D view you get the following:
  

Unlike what you can think
at first glance , the image is 3D
and draped on a DTM provided by ArcGis Pro by default.
To
realize the previous it is enough to increase the
hype vertical sight.

Click on “Scene” in
the legend bar -> Properties -> Elevation surface and change the value by 10, for
example.
Then,
you will see your image in an exaggerated 3D.

Note that the “sea” section of the image
appears
flat at level 0 meter .

Let’s change the MNT by default
for the MNT that we have just created.
To
that end you will use the ribbon, MAP tab
button Add Preset -> Ground
Point
in the DTM file we have created in the first part of the
article .

The
default DEM is
replaced
by the new DTM and the view changes immediately :  

Now you can see
the
opposite of the previous sight: the relief is limited to the marine section,
 the ground isflat
at level 0.

To manage the different DEMs of a view,
you have to use: “Scene” in the caption bar -> Properties ->
Surface Elevation
Then
by
clicking
on “Ground” you will get the list of loaded
DEMs. You have the up and down arrows to
decide which DTM is taken in
consideration
. As for the layers display, in the legend window it is
the one placed highest on the list which is in use.

In the next article we will discuss, how to complete
our
DTM with the terrestrial section.

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