Document 6500422

Aarhus Workbench HOW TO articles series
HOW TO article # 002
Use the GIS
9/11/2013
HOW TO # 002, Use the GIS
www.aarhusgeo.com
Table of content
1. How to use the GIS
2. Step by step guide on HOW TO do it
9/11/2013
HOW TO # 002, Use the GIS
www.aarhusgeo.com
1. How to use the GIS
In this document we will show how to use the GIS. How to use the GIS layer
control to get the right layers in the right order. How to navigate and make
selections on the GIS.
NOTE: This tutorial is connected with other HOW TO articles, such as HOW TO
Add apriori to an SCI (ID # 063), Produce vertical cross sections – getting
started (ID # 081), Process SkyTEM data – manual edits on raw and averaged
data (ID # 016), and Process VTEM data – manual edits on raw and averaged
data (ID # 026).
Refer to the dedicated section of our website
(http://aarhusgeo.com/Software/video-tutorials.html) to access all our tutorials.
In this page you can also find a HD video of this tutorial, and the ancillary files,
compressed in a zip folder, that will allow the Aarhus Workbench user to
duplicate all the steps presented herein.
9/11/2013
HOW TO # 002, Use the GIS
www.aarhusgeo.com
2. Step by step guide on HOW TO do it
Start by opening a workspace with the Aarhus Workbench. If the GIS window
has not already been opened, click on the map node just below the map
windows line in the workspace manager.
The size of the different windows can be adjusted like any other window. This
can be done not only for the workspace manager and the GIS window, but also
for the perhaps less obvious window with the GIS layer control.
Figure 1. The GIS window.
In the map part of the GIS window we have the different layers shown on top
of each other. The order of the layers are given in the GIS layer control on the
right side, from top to bottom. We can change that order either by dragging
the layers around or by right clicking on a layer to send it to the front or to the
back. Each layer can be toggled on and of as needed.
Below the GIS layer control we have filters that can be applied to list of layers.
We can filter on the type of layer, the currently selected visibility of the layers,
and it is also possible to filter on parts of the name of the layers. To the right of
the filters there is a button where we can clear the filters again.
In the same corner we also have the open external GIS layer button. This is
used to add GIS layers based on external files in different formats such as
mapinfo tab files, opengis shape files and geotiffs. This is primarily done to
bring in different kinds of backgroundmap images.
9/11/2013
HOW TO # 002, Use the GIS
www.aarhusgeo.com
In the line below the map we can show a color scale. This color scale can be
set to update with the active layer in the GIS layer control. That is, it will be
based on the last clicked layer in the layer control. Often it is however
preferable to set it to be frozen, so that it doesn’t update when you click
between similar layers. It can also be set to be hidden. Both of the last two
options save a bit of load time. This is not the only way to show a color scale
however, we can also right click on the different nodes in the workspace
manager and select show colorscale from there.
Also in this line we have a map scale, the coordinates of the pointer and the
name of the used coordinate system and projection.
In the upper right corner we have the different tools for navigation, selection
and so on.
Figure 2. A closeup of the upper right corner of the GIS showing the different tools for
navigation, selection and so on.
For navigation there is a pointer. There is a pan tool that can be used to drag
the map around. There is a few different kinds of zoom, and a center tool that
can centers the map where we click on the map.
The zoom options include drag to zoom. Here we drag a rectangle. If the
rectangle is dragged down and to the right, it will zoom in to that rectangle. If
the rectangle is dragged in any other direction, it will instead zoom out by an
amount based on the difference between the current GIS window zoom and the
dragged rectangle.
9/11/2013
HOW TO # 002, Use the GIS
www.aarhusgeo.com
The other zoom option is the zoom to click. Here we click the map, the map is
then centered on where we clicked and zoomed in or zoomed out a fixed
amount. Left click to zoom in, right click to zoom out.
There is one other type of zoom in the GIS layer control. Right clicking on a
layer we can zoom to that layer.
Note the often practical undo and redo arrows for zoom under navigation.
Also under navigation we have a ruler tool for measuring distances on the map.
Simply click on the map to start using it and dobble-click to end. The result is
shown in the lower right corner.
Next we have the selection tools. Selections allows us to do two important
things. It allows us to go in and see the inverted models directy from the GIS.
It also allows us to add apriori to models directly from the GIS when inverting
an SCI.
In order to select something, the layer has to be shown on the map, and also
has to be the active layer in the GIS layer control. Again this just means that it
has to be the last layer clicked.
Figure 3. A closeup of the upper right corner of the GIS showing the different tools for
navigation, selection and so on. This time however the DBQ in the GIS layer control below is
not only on the map, but has also been made the active layer allowing selection from this layer.
The use selection for dropdown for a DBQ selection is also being shown.
There is a number of different way to select. We have the select tool that can
select or deselect single points at a time by clicking on them. We have the
9/11/2013
HOW TO # 002, Use the GIS
www.aarhusgeo.com
select rectangle tool that selects all points within a rectangle by clicking and
dragging a rectangle. We have the polyline select tool that selects points near a
line. Click ones to start drawing the line and dobbelt-click to end. This tool
works best when zoomed in fairly close the the points. Finally we have the
polygon select tool that selects all points within a polygon. Again click ones to
start drawing the polygon and dobbelt-click to end. We can keep adding to a
selection, so there is no need to get everything at ones. We can of course also
unselect everything again. This is done with the last button under selection.
To do something with a selection we need to look under workbench functions
or rather the use selection for dropdown menu.
When making a selection from a DBQ, we can use that selection to show data
and see the data and how the inverted model fits the data. Or we could use the
same selection to make a DBS, which is just a DBQ subset of an existing DBQ
covering only our selection. Other than that and the name, there is no
difference between a DBS and a DBQ.
The exact same selection functionality is used when applying apriori to models
of an SCI from the GIS. Apriori as such will be covered in more details in a later
video, but the typical example is that we want to give a different starting model
to the models over water. So we would select those models of the SCI on the
GIS, little by little if necessary, and then click add add apriori in the dropdown
menu.
There is one other type of selection. If we right click on a profile or a line we
can choose the select in layer option to select point from a given layer within a
given distance to this profile or line. This allows us to easily make a DBS with
the models along a profile.
Finally we will quickly cover a few loose ends about the GIS.
Under navigation we have one last tool called the info tool. It allows us to
select single points directly on the GIS map and read a few entries about it
from the database. Again to select from a layer, the layer has to be shown on
the map and be the active layer. This tool can be useful for reading line file
numbers from the soundings of an SCI, but is otherwise not a tool we will be
needing.
Under draw we have a few options for drawing points, lines and regions and
then saving them as a layer. These layers can then be edited, given labels and
so on by right clicking the layer and selecting edit display in the layer control.
That more or less covers everything about the GIS. There is still a few
important options under workbench functions related to drawing profiles and
processing, but we will return to them in the documents covering those
subjects.
9/11/2013
HOW TO # 002, Use the GIS
www.aarhusgeo.com