Home Application Tutorial Documentation

Application Tutorial Documentation

Introduction Overview Definitions 1. Navigation bar 2. Import/Export options 3. Toolbar 4. Input table 5. Map canvas 6. Map layer options 7. Working-area of the application 8. Room for output Special cases

Introduction

This page is set up in order to get you familiar with the Sky View Factor Web Application. It describes all functions that are available on the application page. If you're looking for a detailed description on underlying methodology, you should check the Documentation page.

Overview

A short description of all the element-groups that are displayed in the image above, further explanation for each element can be found in the next chapter. Every list-item is clickable and refers to the corresponding chapter.

Definitions

The following chapters describe all functionalities that are present on the web application.

Button	Function
Home	Navigates you to the homepage. Information about the project, the group behind this project and contact information can be found here.
Application	Navigates you to the Sky View Factor application.
Tutorial	Navigates you to the tutorial, this page. Information about how to use the web application and website in general can be found here.
Documentation	Navigates you to the documentation. On this page documentation can be found on the processes that are required to create this application.

2. Import/Export options

Button	Function
	Gives you the option to upload a CSV-file containing the coordinates of the points you would like to calculate the SVF value of.
	Lets you download a CSV-file containing the point IDs, coordinates of these points and their respective SVF values.

In order to upload points to the application, they need to be in the CSV (Comma-Separated Values) file format. This file will need the headers X and Y on the first line and their respective values on the following rows. An example of how this would look in the open source text editor Notepad++ is shown in the figure below.

You can download an example by clicking on this link

*Please note that some versions of Excel don't properly load this file.

Button	Function
	Enables the draw-points function. With this button you can draw points on the canvas, these points and their coordinates will be stored in the table on the left of the screen.
	Disables the draw-points function. After clicking on this button you can freely click on the map without creating unwanted points.
	Enables the select-points function. This button lets you select drawn points on the map. If the calculation of the SVF has been done, selecting a point on the canvas will result in the SVF-plot becoming visible on the right side of your screen.
	Enables the delete-point function. This button lets you delete a selected point on the map.
	Enables the ignore-building function. This button lets you remove a building from the SVF calculation process. This can be useful when a user desires to see the effects of e.g. demolishing a certain building has on the SVF of a given location.
	Enables the create-building function. This button lets you draw a building to the map canvas. After you're finished drawing a building (by connecting the end-point to the start-point of your drawing), a pop-up shows requesting the height of the building.
	Enables the undo-calculation function. This button lets the user clear all calculations, so that these can be done again under e.g. different cirucumstances. This can be useful in detecting differences in SVF values before and after adding or ignoring a building.
	Enables the clear-canvas function. This button lets the user clear everything from the canvas and the tables. It is a quick method of restarting your session.
	Enables the calculation function. When all inputs have been determined, this button will start the actual calculation of the SVFs and their corresponding plots.

4. Input table

Label	Description
ID	Refers to the ID of the drawn point. This starts at 1 and counts up after adding more points.
X	Refers to the x-coordinate of the drawn point. This is displayed in the Dutch coordinate system (CRS) "EPSG:28992".
Y	Refers to the y-coordinate of the drawn point. This is displayed in the Dutch coordinate system (CRS) "EPSG:28992".
SVF	The calculated Sky View Factor is displayed here after calculation.

5. Map canvas

The map canvas is the working area of the application. Within the borders of this canvas the user can use the tools in the toolbar.

6. Map layer options

Button	Function
	Gives you the option to change the background layer. The default background layer is the Open Streetmap baselayer. The alternative background layer is an aerial imagery map from PDOK.
	Gives you the option to turn the footprints layer from PDOK on or off. For the aerial imagery background this might prove useful, as the footprints can misalign with the imagery.
	Gives you the option to turn off the zoom on selection option. When this setting is active, you automatically zoom to a point when you select it in the table. If the button is fully visible, this setting is active. When it is inactive, the button becomes transparent.

7. Working-area of the application

The working-area of the application is, in this case, the municipality of The Hague. While it is possible to click and draw on the map outside of the municipality borders, it will not yield results.

8. Room for output

In this area the output will be loaded after calculation. This will be in the form of a fish-eye plot combined with a legend and a table underneath it. Showing the meaning of the colors and the percentages of obstructions caused by either buildings or vegetation.

Special Cases

When you click on a building, the script takes the average height in a 1 meter radius around the point of the selected building. With this height it will calculate the Sky View Factorm, as seen from the top of the building. This is done because it is fruitless to calculate a Sky View Factor from inside a building.

When you click nearby a building, on water, the script takes the average height of the building in the point' proximity. This is due to the fact that the water class has a very limited amount of points in the pointcloud data. Due to this, it is not possible to calculate the Sky View Factor on water nearby buildings.

When you add your own building and afterwards try to calculate the Sky View Factor on top of this building, the application will calculate the Sky View Factor from within this building. This will likely be a near-zero value. This is because the height of the selected point is determined before the addition of the created building.

When calculating the Sky View Factor near powerlines or other infrastructure that is not classified as a building, it will return as vegetation in the fish eye plot that is created. This is due to the limited classifications that are available in the source-data, AHN3. There is no specific vegetation classification, so the script uses the 'unclassified' points for this. This is done because most of the points that are classified as 'unclassified' are actually vegetation.