The Cadastral Cartography Conception- Helge Onsrud

8/2/2019 The Cadastral Cartography Conception- Helge Onsrud

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Norwegian Mapping and Cadastre AuthorityStatens kartverk

State enterprise under the Ministry

of the Environment

National authority for geodesy,topographic data, cadastre, landregister and hydrographicalcharting

16 offices nation-wide Annual turnover approx EUR 1.000

mill

820 staff

Founded 1773


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TIME 100/Scientists & Thinkers

Hernando de SotoUnlocking the Riches of the Poor

Development schemes for Third World countries

rarely benefit the poor, largely because aid is too

often squandered by corrupt bureaucracies. That

makes fresher, commonsense visions like those

of Peruvian economist Hernando de Soto all the

more welcome. De Soto has spent years looking

deep inside the underground economies where

poor people--who make up two-thirds of the

world's population--eke out a living. He figures the

value of their extralegal property, from cinder-block squatter homes to black-market street-

vendor sales, at almost $10 trillion. De Soto

insists that bringing the poor and their assets into

the formal economy, which is usually closed to

them by oligarchies and epic red tape, would

eclipse all previous development efforts.

Development depends on a property

system functioning for all

Hernando de Soto


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Rights

PropertyObjects

Persons


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Rights

PropertyObjects

Persons


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Data about Property Objects

Textual data :

Surface area ,Tax value,Land use

Graphical data : Parcel map or Cadastre Map

Drawings of other property objects

Buildings, apartments

Often referred to as The Cadastre

Confusing terminology


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Role of Cadastre Map

Making it possible to transact; To sell andmortgage more safely;

knowing the location and extent of the parcel

without visiting the boundaries of the parcel Providing information for taxation, land use

planning, etc

Reducing the risk for disputes betweenneighbours

Evidence of boundaries


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What defines a boundary ?

A thing in the field or a line on a map ? Almost everywhere in the World, the legal

understanding is that a boundary is a thing in thefield, marked by special markers, fences, hedges , etc

The realities in the field overrule the map In case of a dispute a good map will be important

evidence

The legal understanding of boundaries, and the role ofthe map in this, should be defined by Law


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Properties are 3 D

Properties extend upwards and downwards

Boundaries are projections of vertical phases

or invisible walls surrounding the parcel

Being a model of the realities in the field the

cadastre map could be 3 dimensional

Coming in very densely built up cities

Not needed elsewhere

Being more and more supported by GIS


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Geodetic accuracy ?

Consequence of the legal role of the map versusrealities in the field

Mostly moderate requirements to geodetic

accuracy Index maps with moderate accuracy most often good

enough

Taxation, land use planning etc do not need high

accuracy SDI - mixing with other geographic data defines the

accuracy standardnot to make spaghetti


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Cadastre maps are established from

various sources

Digitizing old paper maps

Identification of boundaries in orthophotos

Field surveys Surveying not expensive, but very time consuming

to deal with neighbours in the field

The database must give information about the

source and related accuracy for every

boundary corner point


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Content of the cadastre map

Big differences between countries

Recommendation: Make it simple ;should onlycontain data resulting from cadastral surveys Only boundaries, parcel numbers, position of

boundary markers, position of easements if surveyed(+ perhaps building footprints)

Cadastre map is an important component to a

National Spatial Data Infrastructure The full picture only when cadastre maps are

combined with other maps and orthophotos

Service Oriented Architecture and Open Source SW aparadigm shift in cadastre IT


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The Basic rule for cadastre projects

All instruments ensuring maintenance of themaps ( and registers) must be in place beforeone single cent is used on systematic cadastral

projects Organisation and skilled staff

Laws

IT system

Procedures

Affordable costs for all

Documents

The Cadastral Cartography Conception- Helge Onsrud