This document provides information about three QGIS plugins: MapSwipe Tool, Attribute-Based Clustering, and Open Layers. The MapSwipe Tool allows users to compare layers by swiping them horizontally or vertically. Attribute-Based Clustering performs clustering of vector layer features based on attribute values using different algorithms. Open Layers adds various online basemaps to QGIS projects from sources like Google Maps and Bing Maps.
3. INTRODUCTION
• This plugin is a map tool for swipe active layer. The active
layer, or group, will appear above all others.
• This plugin is developed of collaborative form with IBAMA
and APPLIED TECHNOLOGY CO., LTD.
• It allows for the selected layer to be swiped.
8. Click mapswipe and see comparison between
raster and vector layer in the map
9. ADVANTAGES
• The plugin works for both vector and raster layer.
• Can see the difference with others layers below. The active layer, or group,
will appear above all others.
• 'MapSwipe Tool' which can be used to compare imagery side by side. This is
useful when you wish to view an affected area before and after a
catastrophic event.
• You can swipe to compare horizontally or vertically.
12. INTRODUCTION
• Plugin produces clustering for features of vector layer based
on unlimited number of attributes using hierarchical or k-
means algorithms.
• It helps the users to classify features based on the values in
attribute table
• It is available in 2.2.1 version
13. VERSIONS
• 2.0 : update to QGIS 3 - Also new clustering
method added - scipy hierarchical clustering
for unknown number of clusters.
• 2.1 : K-Means2 method added. Links to
original documentation added. Much more
options for scipy algorithms are available.
• 2.2 : Now plugin able to calculate distances
to cluster's centroids for each object. Also
Elbow Method is added to help you figure
out optimal number of clusters.
• 2.2.1 : Broken manual link is deleted
14. INSTALLATION
1
Start QGIS
2
Open plugins menu >
Click manage and
install plugins
3
Select “all” tab, in
the top bar - type
“attribute based
classification”.
4
Select the only item
that appears and
finally press the
button to install in
the lower right corner
(" install plugin" ).
16. OPERATIONS
AVAILABLE
• Hierarchical algorithm is available in two variations: native realization
for known number of clusters and scipy realization for unknown
number of clusters.
• K-means method requires scipy and known number of clusters.
• You can define weight for every attribute, if native hierarchical
clustering used.
• Elbow method for estimating optimal number of clusters is available.
• Also calculating of distances from each object to centroids of each
cluster is available.
.
17. TYPES OF CLUSTERING
K-MEANS
• The method assigns records to each cluster to find the
mutually exclusive cluster of spherical shape based on
distance.
• Needs number of clusters
• Median or mean as a cluster centre to represent each
cluster
• It is less computationally intensive and are suited with
very large datasets.
HIERARCHICAL
• Hierarchical methods can be either divisive or
agglomerative.
• Agglomerative methods begin with ‘n’ clusters and
sequentially combine similar clusters until only one cluster
is obtained.
• Divisive methods work in the opposite direction, beginning
with one cluster that includes all the records and
Hierarchical methods are especially useful when the target
is to arrange the clusters into a natural hierarchy.
18. MERITS
• The major advantage of using this plugin is clustering
fields by more than one attribute
• More over weight is assigned to each attribute which
helps the users to select which attribute must be
more focussed compared to other attribute.
• It has 4 different methods of clustering
19. DEMERITS
• The assigned weight is manual and it doesn’t help
correct clustering in some cases
• Hierarchy method takes a long time to complete
21. INTRODUCTION
• Allows users to add Open Layers base maps to their QGIS projects.
• It is a popular open-source JavaScript library for displaying map data in
web browsers, and it allows users to access this library within the QGIS
environment.
• With this plugin, users can add various base maps, such as Google
Maps, Bing Maps, OpenStreetMap, and many others, to their QGIS
projects.
• These base maps can be used as a background layer for other vector or
raster layers added to the project.
22. INSTALLATION
Open QGIS
2
Open plugins menu >
Click manage and
install plugins
3
Select the settings
tab > Enable all the
experimental
plugins
4
Select the “all” tab,
and in the top bar -
type “Open layers”.
5
Click open layers >
Install plugin
6
Within few seconds
plugin will be
installed.
1
27. API
• Application programming interface key is a
code passed by computer applications or
programs to identify the calling application
and authorize access to a particular API.
• The API key serves as a unique identifier for
the developer and ensures that only
authorized requests from their application are
processed by the API.
28. MERITS
• Free and open-source software.
• Provides a wide range of customization
options ie, support for multiple map
projections, vector and raster data layers, and
custom styles and labels.
29. DEMERITS
• Challenging for beginners to learn as it uses computer
languages, like java.
• May not be fully compatible with some older browsers, which
can limit its usability for some users.
• It requires unique codes like API.