0806514_family activity centre report (1)

Principles of GIS – Map and Report 0806514

1 |4


2 |4

INTRODUCTION:

This report aims to justify the proposed location of a new family activity centre on the banks

of Loch Lomond and explain the procedures used to obtain its conclusion.

CRITERIA:

The selected family activity centre location based at a car park must satisfy the following:

(1) Where water depth is between 3 and 20m

(2) Where substrate is more than 150mm

(3) Within 1Km of the West Highland Way

(4) Within 1000m of a car park

SETUP:

(i) A personal geodatabase was set up to use the British National Grid (BNG) coordinate

system and a feature dataset was added containing the following shape files:

- BOATS.shp (containing polygon data)

- WHWAY.shp (containing polyline data)

- CARPARKS.shp (containing point data)

This ensured the shape files had the BNG set as their coordinate system.

(ii) A blank map document was created in ESRi Arc Map and the environment was set up.

The current and scratch workspace was set to the TOURISM.gdb and the processing

extent and Raster Analysis were set up. The Layers coordinate system was set to

BNG through the Layer Properties.

(iii) The files held within the feature dataset were added into Arc Map.

(iv) The depth and substrate text files were then added into Arc Map through:

File > Add Data > Add XY Data

This created and plotted a point layer for depth and a point layer for substrate based

on the X, Y and Z values contained within the .txt files.


3 |4

METHODOLOGY:

Generation of suitable areas was performed by using a combination of raster interpolation,

reclassification, raster calculation, vector buffering and intersection. Raster to Vector

conversion was later used to add symbology to the raster calculated depth and substrate

layers for aesthetic purposes.

(i) Raster Interpolation (3D Analyst/ Raster Interpolation / IDW):

The depth and substrate XY layers were interpolated using the IDW tool within the Arc

Map Toolbox to create surfaces from the point data.

(ii) Reclassification (Spatial Analysis/ Reclass/ Reclassify):

The depth layer was reclassified into three classes (0-3, 3-20 and 20-150) with the 3-

20 values reclassified to the value of 1 to satisfy the depth of between 3-20m criteria

and all other values reclassified to 0. This is shown in the screenshots directly below:

The substrate layer was then reclassified into two classes (0-150 and 150-500) with

the 150-500 values reclassified to 1 to satisfy the substrate of more than150mm

criteria, all other values were reclassified to 0. This is shown in the screenshots below:


4 |4

(iii) Raster Calculation (Spatial Analysis/ Map Algebra/ Raster Calculator):

Reclassified depth and substrate layers were multiplied together using the raster

calculator to create a layer of ‘good water’ where criteria 1 and 2 were both satisfied,

depth 3-20m and substrate >150mm. This is shown in the screenshot below:

(iv) Buffering (Analysis Tools/ Proximity/ Buffer):

A buffer of 1Km was created around the West Highland Way and another buffer of

1000m was generated around the car parks.

(v) Intersection (Analysis Tools/ Overlay/ Intersect):

The West Highland Way and Car Park buffer layers were then intersected to identify

the areas where both criteria 3 and 4 were satisfied.

(vi) Raster to Vector Conversion (Conversion Tools/From Raster/Raster to Polygon):

The ‘good water’ layer was converted into raster and the features of value 1 were

selected by attributes, using ‘gridcode’ = 1. A new layer was created from the selected

features and the symbology changed to make it visually unique from the ‘good water’

layer. The ‘good water’ layer was used as the Loch Lomond outline and ordered above

the buffers to show that the suitable and recommended areas were on land by

obscuring the buffers in the water.

Suitable area polygons were selected and a new ‘Suitable Family Centre Locations’ layer

created from the selection. The recommended location was then selected by zooming into

the suitable areas for closer inspection; justification is displayed on the map layout. The

recommended location polygon was selected with the selection tool from the new suitable

location layer and a new layer created so that the symbology of the recommended location

could be unique from the suitable locations for emphasis.

0806514_family activity centre report (1)

Documents