How to use Landsat Images ( Free ) with QGis 2.8 for NDVI

In the previous two articles, we have discussed ( How
to use Landsat images (free) with ArcGIS (ArcMap) for NDVI
, How
to use Landsat images (free) with ArcGIS Pro for NDVI
) the calculation and
display of NDVI with ArcMap and ArcGis Pro. In this article we will
discuss how to achieve this
operation
with QGis.
To
download Landsat images from Earth Explorer, check out
this
article: How
to use Landsat Images ( Free ) in
your GIS .

Here we will use the raster calculator to calculate the NDVI
, then we will discuss how to create and use a specific colour
gradient for this index.
 

If you work with a Landsat 7 image,
you will load in QGis the bands 3 (red) and
4 (infra-red). If you work
with a Landsat 8 image you will load the bands 4 (red)
and 5 (infra-red).  


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How to use Landsat Images ( Free ) with ArcGis Pro for NDVI

In the previous article, How to use Landsat Images ( Free ) with ArcGis (ArcMap) for NDVI, we have dealt with the calculation and display of the NDVI index with ArcMap. Here, we will discuss how to achieve the same operation with ArcGis Pro. We will start by using the composite image , created with the tool ” Composite channels ” also directly available at the ArcGis Pro “Geoprocessing” window.   

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How to use Landsat Images ( Free ) with ArcGis (ArcMap) for NDVI

In a previous article,   How to use Landsat images ( free ) in your GIS , we discuss how to download Landsat 7 or 8 images. Now we will discuss how to use them with ArcGis, when you use ArcMap or ArcGis Pro.

We left at the point where you had , in a directory , a series of 8   or 11 tiff images. Each of them corresponds to a satellite band . Landsat 7 images have 8   bands while the Landsat 8 have 11.

For the calculation of the NDVI you will need the band corresponding to the red and the near infra-red:

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ArcGis Pro: the attribute tables management

We will continue discussing those little details worth knowing to be able to switch from working in ArcMap to ArcGis Pro. In ArcMap, you display the attribute table with the right click on the layer in the legend window and open the table , or by clicking on properties -> fields to view and edit the table structure. In ArcGis Pro, just the first part is similar . If you want to work on the structure of the table you must use the following option in the layer menu : “Design” then “Fields” ( or Domains, or Subtypes if you must take action on them ).

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ArcGis Model Builder: Expanding a Model to an Input Dataset

There are always two psychological barriers to overcome with Model Builder:

  • the first one is deciding to, actually, use it and move from the interactive, natural working mode to ArcMap, i.e. to a working mode where all the workflow is performed virtually, before actually launching it
  • the second, when you are, already, comfortable with the tool and start creating increasingly complex models, but always based on an input layer producing an output layer. And then, you think it would be nice to be able to apply the model automatically to a whole batch of input data, and somehow you find out that it is necessary to use “iterators”.
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How to edit OpenStreetMap data with ArcGis

The “ArcGIS Editor for OpenStreetMap” toolkit lets you use ArcGIS tools to work on OpenStreetMap data. This set of tools for ArcGIS 10.X allows you to load OpenStreetMap data and store it in a geodatabase. Afterwards, you can use the ArcGIS Desktop editing environment to create, edit, network scan, or update data. Once editing is completed, you can post changes to OSM to make them available to all OSM users.

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Starting with ArcGis Pro: create your own source of elevations ( 3)

To conclude the creation of our own source of elevation , started in previous articles( Starting with ArcGis Pro: create your own source of elevations ( 1) and (2) ) we are going discuss the use of the raster calculator with ArCGis Pro.
We have two different areas in our work surface:

  • a terrestrial area

  • a marine area
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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 .

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