SLICER


2 – Example of creating a Hypsometric Map


This example uses a Digital Elevation Model (DEM) obtained freely in http://www.webmapit.com.br/inpe/topodata eletronic address. This is the original data SRTM that after processed were structured grids available in GeoTIFF format (.tif), referenced in latitude / longitude (no projection), with coordinates in decimal degrees and WGS84 datum. We perform the download “08S435ZN.tif” file, related to altitude data, unpack and carry the QGIS layers panel.




Open the Plugin Slicer window.




In order to make the image slicing will follow the steps as suggested in Figure below:




1° - Find the name of the input raster file we want to slice in the case, "08S435ZN.tif";

2° - Enter the name of the output raster file in the case, "Map_Hipsometria_Altitude.tif";

3° - Keep the "Add To Raster Layers Panel" marked to add the output raster to QGIS layers panel;

4° - Keep the "Compress Raster" marked to compress the output file, avoiding waste of hard disk space;

5° - Check the minimum and maximum values of the pixels of the image, related to altitude;

6° - In this example the type of step (Step) will be the "Fixed" option, to obtain slices with equal intervals;

7° - In the "Initial" enter a value lower than the "Minimum Value" in the case, 150 meters;

8° - In the "End" key in a value at or above the "Maximum Value", in this case, 700 meters;

9° - In the Field "Step" enter a value to set the interval between the minimum and maximum values of the slices in this case the step is 50 meters;

10 - Click the "Add" to add the slices in the list box "Slices" button;

11 - You can check the slices that have been added in the list box, and can remove any slice marking the selection to the left of each slice box and following click the "Remove" button;

12 - Finally, click the "Slice" button to start the slicing process.




Choose the appropriate SRC in this case will be the WSG84.




You will see a dialog box stating that the process was successful, click the "OK" and then in the Slice window click the "Close" button to close it.




Note that our hypsometric map was added to the layers panel.




Now, let's coloring our map. Enter the Layer Properties window and the style guide make the setting described in the figure below:







1° - In the selection "Render type" box, select the "Sigleband pseudocolor" option;

2° - In "Generate new color map" select "RdYlGn";

3° - Select the "Invert" box;

4 - Select the "Min / Max" option;

5° - Click the "Load" button;

6° - In the "Mode" check box, select Equal interval ";

7° - In "Classes" enter the value 11, referring to the number of classes (slices);

8° - Click the "Classify" button;

9° - In the list box with the slices, change the values of the labels, as shown;

10° - Click the botãp "Apply";

11° - Finally, click the "OK" button.


See how was our map: