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Saturday, 30 November 2013

Myths & Common questions about Mapping

As a map-maker, I often get  questions related to my field as the world, frustrating as it sounds, do not what is mapping is all about. Likewise, any map-makers do get a lot of questions and that is our unique signature as map-makers, rare species indeed.

I decided to make this video to address some of the common questions/myths related to mapping. Having said that, not much preparation was made for the script. I was talking impromptu at some sections. Even setting up the scene and choosing the clothes took 20-30 minutes.  The position, lighting, location of the tie etc...

I would like to thank my dear friend for spending time in setting up the scene, lighting and filming at late night. I credit him for the success of the  video. Hence, first time, I am looking for points of improvements for the content and the filming.

Thanks for Watching! Happy Commenting!

Sunday, 24 November 2013

Implementing GIS to tackle local government issue - Part 6 (Final)

Part 5:

Geoprocessing in Information Product production

Geoprocessing for Datasets to be ready

Geoprocessing for generating Information Product


City of Yarra, 2012, Your Council, City of Yarra, viewed on 2nd April 2012,

Services (Community Planning), 2011, ‘Social and Affordable Housing Strategy’, City of Yarra, viewed on 2nd April 2012,

Services (Community Planning), 2009, ‘Public Health Plan’, City of Yarra, viewed on 2nd April 2012,

Implementing GIS to tackle local government issue - Part 5

Part 4:

Conceptual Design

Data design

The key data element of address dataset that would be logically linked with community facility table would be EZI_ADD. The reason this element is crucial is because EZI_ADD is used to geocode the facility address. For this linkage to be successful, the addresses of the community table must be identical of format and address representation.

The minimum map area is 0.01 hectares, based on CCD .The error tolerance for this project is 10%, to match the error tolerance of dataset’s positional accuracy. The map scale desired for the project would be 1: 1000. The map projection that should be employed for the project area is MGA Zone 55 as this projection minimizes distortions for the region. Temporal resolution would be every year to cater annual needs of the city.  

Data sources for this information product come from DSE (public source). The lineage of address dataset starts from derivation from address information found in Vicmap Property and Vicmap transport. The addresses were later analysed and categorised and channelled the results to address dataset. This address dataset has address match rate of 92% (2008/09). The data standard I will employ in this project would be ANZLIC Metadata Product Guidelines VER 1.2 July 2011. The reason I chose this standard is because the metadata format for the DSE datasets are based on this and applying the same standard would fasten the process of writing product description. Since the datasets found are readily available in ESRI shapefiles, there will no need for data format conversion.

Logical Data Model

Most or all the dataset structure for the project would be vector-based. Below-here is an example the characteristics of vector transportation dataset.
Data Type
Object ID
Long Integer

The suitable structure for the data is object-relational data model. It allows addition of specialized behaviour to the relational data model which is close to real world behaviour.
The advantages of this model would be it maintain high data integrity, multiple users are able to update simultaneously and allows use of legacy and GIS databases. For the project, this model is chosen because ArcGIS software uses this model and it allows wide range of relational and objects rules to be applied. Disadvantages would be it is compromise of two previous models and difficulty of modelling complex relationships.

For attributes to be linked with the administrative dataset, the geo-relational data model is most appropriate model for storage and manipulation of the data. This is because the parcel boundaries are able to be linked easily with other tables containing data of population characteristics.

The model (incorporating relational and objected orientated models) allows relational data model to have object-orientated extensions. This means various relational and object-orientated rules are applicable which are needed for the project dataset (parcel layers and network datasets). Secondly, its ability to allow multiple, simultaneous updates would maximise GIS analyst working efficiency. For example, one GIS analyst would be using series of datasets to analyse accessibility to clinics while another analysts would use the same datasets for another analysis.

Part 6 (Final):

Saturday, 16 November 2013

Implementing GIS to tackle local government issue - Part 4

Part 3:

Master Input Data List

The GIS datasets required for the strategy are address, administrative boundaries, planning zones, property and transportation network. The non-spatial data required are population, income and employment status data and table of community service facilities (e.g. clinics). The address dataset would be utilized to geocode address of community service facilities and population characteristics data. Administrative boundaries dataset would be used in defining the council area and linking population data to census collection districts (CCD). 

Planning dataset shows planning polygons as this would be important in determination of future housing areas. Property dataset shows the location of parcels and its attributes and would be used in determination of number of residential lots could be impacted in this strategy. The tables of population characteristics and facilities would be utilized to assess the level of accessibility to facilities.

I shall examine address dataset in depth. The reason I chose this dataset is because it underpins the success of strategy and hub of connecting of non-spatial data and GIS datasets. Tables containing facility data and population characteristics are geocoded into the address dataset. This geocoded facilities/population data would work together with other datasets in the various geoprocessing methods.

Data identification Items:

     1) Dataset Name: VicMap Address
        (a) Identification No: ANZVI0803002578
        (b) Source/Custodian: Department of Sustainability & Environment (DSE)
        (c) Metadata: Spatial Extent- 34.0S-39.2S, 141E-150.2E. Spatial Reference- GDA94. Positional    accuracy- 90% of features are within 1mm at plot scale, of true position (5-25m). Attribute accuracy-1%-5% allowable error. Logical Consistency-1%-5% allowable error. Currency- 2012(time of writing)

Data Volume:

        (a) Volume:124MB
        (b) Format available: ESRI, MapInfo, DXF,DWG

Data Characteristics

Datasets available are in the ESRI shapefiles. Below here are the fields of address dataset will be used. Minimum spatial extent for the project is 144.963 E to 145.045 E and 37.777 S to 37.835 S.

Data Type
Allow Null Values
Object ID

Source Data Availability

City Council is able to access the dataset required from DSE and it is fully in digital format (e.g. shapefiles).


No restrictions/royalties placed on the usage of datasets as this for council use (non-profit).

Part 5:

Implementing GIS to tackle local government issue - Part 3

Part 2:

Steps Required Making the Product:

     1) All the datasets are compiled and stored in a geodatabase. The metadata and the projections used in these datasets are checked to ensure consistency. Functions needed are data inputs into geodatabases (network, feature datasets)

         2) Since the product (Current Accessibility of City of Yarra) involves various maps, analysis on datasets are done separately to simplify the operations. For example, GIS analyst focusing on clinical accessibility would use datasets on population characteristics, transportation network and clinical locations. The analysis would involve network analyst and geocoding addresss. The GIS analysts may consider imposing index values for accessibility.

     3) Once the maps are done, the GIS analyst(s) should ensure the maps produce meet good quality cartographic standards. These maps initially produced in hardcopy format are submitted to town planning officers to assess the current accessibility.

     4) A web-enabled GIS is created meantime integrating the spatial data used in the project. GIS analyst(s) and/or cartographic technicians will design the website and the necessary characteristics of the online maps. This website is accessed to city council’s intranet. At the same time, list of existing facilities and the total targeted population (income disadvantaged) served are produced in documents (hardcopy formats).

Frequency of Use:
Dataset Input
Geocoding addresses
Creating Network dataset
Population characteristics input
Spatial Analysis (Closest Facility)
Create ArcGIS reports
Cartographic Editing
Display in website
List/other documents production

Annual Production
Maps (Hardcopy)
Lists/Documents generated

Logical Linkages:
Logical Linkages
List to graphic entity
Street address to community service facilities
Map to map
Topological network of the map overlayed on residential maps
Facility map showing locations to community service facilities
Attribute to attribute
Population characteristics to census collection districts
Type of clinic to clinic locations
 Error Tolerances:
Error Type
Incorrect facility attributes
Incorrect facility names
Disconnect in street networks
Disconnect in public transportation network
Incorrect locations of public transport stops (wrong side of street)
+ 5m
Incorrect street address


Wait Tolerance: Low (10-60seconds) and Medium (1-5 minutes). These tolerance categories are justified for the products as there are not urgent in production and they have limited dynamics.

Response Tolerance: For hardcopy maps, the time required from start to finish is 8 hours minimum. This has taken into consideration of the GIS officer has 1 year working experience in GIS and the analysis involved in producing the map. If the product was requested for the first time, it will be 16-24 GIS hours work due to datasets cleaning and other associated works. For the website, it will be additional 8 hours minimum, in addition of 2 hours of integration of GIS data into the online system. The updates to the online GIS system roughly consume maximum of 3 hours.

Current Costs:

      1) GIS dataset costs

Administrative Boundaries

      2)   Labour, other related and Total costs

Annual Cost for making
Total Costs (AUD)
Labour (hardcopy)
$192*(1 product)
Labour (website)



           *-Excluding website cost. Hourly rate is minimum $23 per hour

Benefit Analysis:

      1) Financial savings category: With implementation of GIS in this strategy, it would eliminate costs required to hire consultants.

      2) Direct benefits to organisation: With GIS, the town planners are able to make informed decisions of providing facilities. They too would be able to estimate appropriate costs involved through the output maps.

c    3) External benefits: The general public will be well served indirectly through GIS implementation. The future facility and affordable housing will be well placed to serve the disadvantage population. The state government is able to access these maps or web-GIS to assess the achievements of city council.

Sign off: The head of SPU will be signing off the IPDs and benefit analysis statements. Finally, every sample hardcopy product must require signature of the head to demonstrate his/her satisfaction of the product.