Using Google Maps Sunday 9th Sept. 2012 H.A. Nandalal, TTLS nanco@tstt.net.tt

Using Google Maps

Sunday 9th Sept. 2012

H.A. Nandalal, TTLSnanco@tstt.net.ttwww.survplan.comwww.survtools.com

Using Google Maps

What is “Google Maps”?

Google Maps is a publicly availableGeographic Information System (GIS)Base Map from Google Inc.

It is accessed on the internet usingweb browsers:

Chrome v21Firefox v14Internet Explorer v9

http://maps.google.com

Using Google Maps

The GoogleMaps

Interface:

Zoom Control

Pan Control

Map TypeMenu

Scale Bar

Using Google Maps

What’s Shown on

The Map?

“Map” Mode:

RoadsBuildings

RiversPts. of Interest

Using Google Maps

What’s Shown on

The Map?

“Satellite” Mode:

RoadsBuildings

RiversPts. of Interest

onAerial

Photography

Using Google Maps“Satellite” Mode: Max. Zoom = 1m Resolution

Using Google Maps

How Can We Use“Google Maps”?

1. Get Information

2. Put Information

Using Google Maps

GettingInformation

from theBasic Map

WGS84Geodetic

Co-ordinatesin

Decimal Degrees

http://maps.cga.harvard.edu/gpf

Using Google Maps

What’s theMethodologyfor Getting

Information fromGoogle Maps?

By usingJavaScript

& the GoogleMaps API:

Application Programming

Interface

Using Google Maps

What isJavaScript?

A ScriptingLanguage

which allowsUsers toInteract

withthe Elements

of aWeb Page

Using Google Maps

Let’s take aLook at the

Source Codeof the ISTTHome Page

Using Google Maps

The Web Pageis written inHyperText

Markup Language(HTML).

The JavaScriptCode is in a

Separate File with Extension “js” and

is Linkedto the Web Page

with a“<SCRIPT>” TAG

Using Google Maps

The JavaScriptCode:

Functions &“ if ” Statements

which can’tbe found in

HTML

JavaScriptAllows for

Computations&

Decision-Making

Using Google Maps

Let’s Create a Google MapsWeb Page from Scratch:

1. Some HTML Code

2. Some JavaScript Code

3. Load files into a Web Browser

Using Google Maps

13 Lines ofHTMLCode

Line 7 Linksthe

JavaScript File

Line 11 is a“DIV” or

Rectangleto PlaceThe Map

Using Google Maps17 Lines of

JavaScript Code

Line 4 Linksthe “DIV”Rectangle fromThe Web Page

Line 6 Defines the Map Centre

Line 12 Defines the Map Type

Line 15 Draws the Map

Using Google Maps

The Resultfrom

30 Linesof Code

Using Google Maps

Let’s Change

TheMap Centre

TheZoom Level

&

TheMap Type

Using Google Maps

The UpdatedMap:

27-28Crichlow St.

San Fernando

Using Google Maps

TheCo-ordinates

onGoogle Earth

&Google Maps

WGS84Geodetic

Using Google Maps

ComparingUTM

Co-ordinateson

Naparima&

WGS84Datums

Using Google Maps

To Convert

FromNaparima UTM

ToWGS84 UTM

+ 170 E+ 184 N

To Convert

FromWGS84 UTM

ToNaparima UTM

- 170 E- 184 N

Using Google MapsTransforming Geodetic Co-ordinatesBetween WGS84 & Int. 1924 Datums

Using Google Mapswww.survtools.com/tools/molodensky/molodensky.htm

Online Calculators forPerforming Geodetic Transformations

Using Google Maps

Putting Informationon Google Maps

Using Google MapsPutting Information on Google Maps:

Polygons for Wards, Boroughs, Cities & Parishes

Using Google MapsUsing the Polygons for Wards, Boroughs, Cities & Parishes:

Getting Cadastral Information from a Co-ordinated Point

Using Google Maps

Using Google MapsA Basic GIS Application: Performing a Radial Search

Using Google MapsAnother GIS Application:

Plotting “Un-Indexed” Cadastral Plans

Using Google Maps

Performing a Radial Search for Cadastral Plans

Using Google MapsAdding Images to a Google Maps Web Page

Using Google MapsThe Cadastral Plans Demonstration Web Site:

http://www.survplan.com/boxfile/boxfile.htm

Cadastral Plans Contributed by:

Mr. Winston DoyleMr. Barry HernandezMr. Trevor Koylass

Mr. Winston MohammedMr. Harvey Ramrekha

Mr. Kamal SantMr. Nicolas Westmass

Mr. Glenn WilkesMr. Burton WilliamsMr. Paul Williams

THANK YOU!