Overlay Analysis: Spatial Join Map

Aim:

To create perform overlay analysis of two (digitized) Feature datasets, using  Spatial Join method.

Procedure:

Concept:   Spatial Join is for geometrically similar or rather same shape features. The demographic datasets, for example is diverse, but for a same location or shapefile in ArcGis terms. Here, however, to illustrate the Overlay analysis using Spatial Join, tool, we will use the same two polygon feature class. This works more like intersect, retaining the water bodies only! Since that’s that only shape geometry that is same or identical to the common features of the two feature classes.

Step 1: Map Input

Identify the two layers that can be digitized from your toposheet or base map. For this session, Forest Area and Waterbodies (Perrinial) were digitized from the given topographic map of Nellore & Cuddapah Districts.  The Polygon Entities were saved into respective shapefiles in target ArcCatalog Folders. 

Step 2: Map Processing

• ·         Digitize the Polygon features for selected entities. Perform Attribute Editing. “Add Field” for “Name” and “Area”.  Specify the Names and calculate geometry to calculate shape area.  (note to calculate geometry, the features need to be on Projected coordinate system).
• ·         Locate the “Spatial Join” tool in Analysis -> Overlay, toolbox.
• ·         Define the Tool Input “Forest” and join feature as “Waterbodies” and specify the target output folder. 
• ·         Click “Ok” to generate the map output

Step 3: Map Display

Create Custom Map Layout with the necessary map elements and Export map to Jpeg format. It’s best to display map outputs in three data frames, one for the Overlay Output ad two for displaying th input feature classes.  One may also choose to Add Attribute table to layout, an option available within the Table options.

Conclusion:

Spatial Join map for the chosen polygon attributes layers are generated using ArcGis 10.1.

Overlay Analysis: Intersect Map

Aim:

To create perform overlay analysis of two (digitized) Feature datasets, using  intersect  method.

Procedure:

Concept:   Intersect tool performs a kind of overlay analysis, where common features, which intersects between,  the new dataset or Target layer and the another data set or layer,  will be retained.

Step 1: Map Input

Identify the two layers that can be digitized from your toposheet or base map. For this session, Forest Area and Waterbodies (Perennial) were digitized from the given topographic map of Nellore & Cuddapah Districts.  The Polygon Entities were saved into respective shapefiles in target ArcCatalog Folders. 

Step 2: Map Processing

• ·         Digitize the Polygon features for Selected entities. Perform Attribute Editing. “Add Field” for “Name” and “Area”.  Specify the Names and calculate geometry to calculate shape area.  (note to calculate geometry, the features need to be on Projected coordinate system).
• ·         Locate the “Intersect” tool in Analysis -> Overlay, toolbox.
• ·         Define the Tool Input “Forest” and intersect update feature as “Waterbodies” and specify the target output folder.
• ·         Click “Ok” to generate the map output

Step 3: Map Display

Create Custom Map Layout with the necessary map elements and Export map to Jpeg format. It’s best to display map outputs in three data frames, one for the Overlay Output ad two for displaying the input feature classes.  One may also choose to Add Attribute table to layout, an option available within the Table options.

Conclusion:

Intersect  map for the chosen polygon attributes layers are generated using ArcGis 10.1. 

Overlay Analysis: Identity Map

Aim:

To create perform overlay analysis of two (digitized) Feature datasets, using  identity method.

Procedure:

Concept:   Identity tool performs a kind of overlay analysis, where features in the new dataset or Target layer will wholly be retained, while selected features from the other layer (Old layer, usually), which overlap the new or target layer, will be retained.

Step 1: Map Input

Identify the two layers that can be digitized from your toposheet or base map. For this session, Forest Area and Waterbodies (Perennial) were digitized from the given topographic map of Nellore & Cuddapah Districts.  The Polygon Entities were saved into respective shapefiles in target ArcCatalog Folders.  

Step 2: Map Processing

• ·         Digitize the Polygon features for Selected entities. Perform Attribute Editing. “Add Field” for “Name” and “Area”.  Specify the Names and calculate geometry to calculate shape area.  (note to calculate geometry, the features need to be on Projected coordinate system).
• ·         Locate the “Identity” tool in Analysis -> Overlay, toolbox.
• ·         Define the Tool Input “Forest” and identity layer as “waterbodies” and specify the target output folder.
• ·         Click “Ok” to generate the map output

Step 3: Map Display

Create Custom Map Layout with the necessary map elements and Export map to Jpeg format. It’s best to display map outputs in three data frames, one for the Overlay Output ad two for displaying the input feature classes.  One may also choose to Add Attribute table to layout, an option available within the Table options.

Conclusion:

Identity map for the chosen polygon attributes layers are generated using ArcGis 10.1.

Thiessen Polygons: Point Entities

Aim:

To create a Thiessen Polygons for the given Map using the chosen Point attributes.

Procedure:

Concept:   Entities have area of Influence, which we can tag as “Service Areas” or “Sphere of Influence”. For Example, Post Offices that cater to particular zone, Places of religious worship that is accessible to the residents of a particular zone,…   Now, though these are completely two different entities, there could be instances where a particular feature types is repeated at a closer proximity within a zone.  Example, a section in the zone which has two temples. Now which temple would be more proximate to which part of the zonal section?  Another more obvious example will be habitats which have their own spatial areas of habitation, there is no physical or political boundary here, but just the sphere of influence, based on the distance between two or more entity features.  The non-uniform spread of features uses its own distance weighing attributes to compute Influential Zones of Polygons.

Step 1: Map Input

Identify the Point entities component for the location dataset. For this session, Post Offices and Temples (Hindu Place of Worship) were digitized from the given topographic map of Nellore & Cuddapah Districts.  The Point Entities were saved as “Civic Areas”.

Step 2: Map Processing

• ·         Digitize the Point Entities for Selected entities. Perform Attribute Editing. “Add Field” for “Name” and “Weights”.  Specify the Name (Temples or PO) in the Attribute Window.
• ·         Locate the “Create Thiessen Polygons” tool in Analysis -> Proximity, toolbox.
• ·         Define the Tool Input “Civic Areas” and specify the target output folder.
• ·         Click “Ok” to generate the map output

Step 3: Map Display

Create Custom Map Layout with the necessary map elements and Export map to Jpeg format

Conclusion:

Thiessian Polygon maps for the chosen polygon  attributes are generated using ArcGis 10.1. 

Variable-Ring Buffer Map: Point Entities

Aim:

To create a Variable-Ring Buffer Map using the chosen Point attributes.

Procedure:

Concept:   Entities cater specific, which we can tag as “Service Areas” or “Sphere of Influence”. For Example, Post Offices that cater to particular zone, Places of religious worship that is accessible to the residents of a particular zone,…   Now, these are completely two different entities, catering for completely two different purposes. So how do we show the buffer areas for entities of these types, where the buffer zones are specific to the character? The buffer value varies or is unique to the Feature type and this needs a map that calls for representing this Uniqueness. Variable Buffer is the Tool of solution

Step 1: Map Input

Identify the Point entities component for the location dataset. For this session, Post Offices and Temples (Hindu Place of Worship) were digitized from the given topographic map of Nellore & Cuddapah Districts.  The Point Entities were saved as “Civic Areas”.

Step 2: Map Processing

• ·         Digitize the Point Entities for Selected entities. Perform Attribute Editing. “Add Field” for “Name” and “Weights”.  Specify the Name (Temples or PO) and Assign respective weights in the Attribute Window.
• ·         Locate the Buffer tool in Analysis -> Proximity, toolbox.
• ·         Define the Tool Input “Civic Areas” and now select the radial icon for “Field” choose “Weights” from the Drop Down. The Buffer will be computed for the Custom Quantity, here weights and generated as , map outputs
• ·         Click “Ok” to generate the map output

Step 3: Map Display

Create Custom Map Layout with the necessary map elements and Export map to Jpeg format

Conclusion:

Variable -Ring Buffer maps for the chosen polygon attributes are generated using ArcGis 10.1. 

Multi-Ring Buffer Map: Polygon Entities

Aim:

To create a Multi-Ring Buffer Map using the chosen polygon attributes.

Procedure:

Step 1: Map Input

Identify the polygon component for the location dataset. For this session,  water bodies were digitized from the given topographic map of Nellore & Cuddapah Districts.

Step 2: Map Processing

• ·         Locate the Multi-Ring Buffer tool in toolbox. In this session “Multi-Ring” tool in Proximity toolset was chosen.
  
• ·         Define the Tool Input “Polygon” and  the linear Distances that will be computed as buffer distance (0.5, 1 and 2 Kilometers respectively) and specify the target output location
• ·         Click “Ok” to generate the map output

Step 3: Map Display

Create Custom Map Layout with the necessary map elements and Export map to Jpeg format

Conclusion:

Multi-Ring Buffer maps for the chosen polygon  attributes are generated using ArcGis 10.1. 

Buffer Map: Spatial Entities

Aim:

To create a Buffer Map using the chosen point, Line and Polygon attributes.

Procedure:

Step 1: Map Input

Identify the point, Line and Polygon attribute component for the location dataset. For this session, the settlements were digitized from the given topographic map of Nellore & Cuddapah Districts.

Step 2: Map Processing

• ·         Locate the Buffer tool in toolbox. In this session “Buffer (Analysis)” tool was chosen
• ·         Define the Tool Input “Settlements”, “Road” and “Waterbodies” Features and  the linear Distances that will be computed as buffer distance (300 meters, 100 meters and 5 Kilometers respectively) and specify the target output location
• ·         Click “Ok” to generate the map output

Step 3: Map Display

Create Custom Map Layout with the necessary map elements and Export map to Jpeg format

Conclusion:

Buffer maps for the chosen point, Line and Polygon attributes are generated using ArcGis 10.1.