geoprocessing in gis from geodata acquisition to...

Jaromír Kolejka - Mendel University of Agriculture and Forestry in Brno1

Socrates – Erasmus Summer School: Full Integration of Geodata in GIS

Geoprocessing in GIS

From geodata acquisition to geoprocessingThe nature of geodata

1. The geodata source isthe landscape.

2. Visual and otherlandscape features are transformed intogeodata.

3. The geodata acquisitionis represented by mapping procedures.

4. Mapping procedures are realized by mappingtechniques andtechnologies.




From geodata acquisition to geoprocessing

1. Thematic mapping is theumbrella title for specificgeodata acquisition fromcertain territory.

2. Every thematic mappingis being carried outseparately from theothers.

3. Every thematic mappingis being carried out by specialists.

4. Analytic geodata are typical products ofthematic mapping.

The nature of geodata




From geodata acquisition to geoprocessingThematic mapping technologies: 1) field mapping – primary geodata, 2)

laboratory archieved geodata processing – secondary geodata, 3) remotelysensed geodata – primary geodata, 4) overlay, internet etc. derived data –

tertiary geodata




From geodata acquisition to geoprocessingAdvantages and disadvantages of acquired geodata from the viewpoint of its

application in GIS:

1) field mapping – primary geodata, self responsibility for data quality, wide rangeof knowledge necessary, long time of field work, traditional and present technology suitable (GPS, PDA, iPEG etc.),...

2) laboratory archieved geodata processing – secondary geodata, varyingreliability, different geometric and quality features, preprocessing necessary,...

3) remotely sensed geodata – primary geodata, introductory investment, complexprocessing, expensive technology, coverage, synchronous, homogenous quality,...

4) overlay etc. derived data – tertiary geodata, different scales, formats, geometry, sources, accessibility, expenses, varying quality and reliability, complex collectionand processing,...




Thematic (analytic) Geodata IntegrationRules:

1. Keep relationships natural for factors described by geodata set.

2. Keep resolution representing the working scale(resolution).

3. Apply landscape ecological (or physical-geographical) knowledge.

4. Testify factor combinations derived by GIS procedures.

5. Consequent two-by-two layers integration prefered to total all-layer integration.




GIS software geodata integration offerArcView v.3.1 data integration examples




Thematic (analytic) Geodata Integration

Intersection of overlaid geodata sets

Traditionalapproach





Examples of typicalgeodata sets

All these data setsrepresent

products ofmutually

independent thematic mapping.

All these data sets are integrated from followingviewpoints: format, scale, resolution, coordinate system, map projection





Example of overlay of threedata layers with consequent

intersection.




Thematic (analytic) Geodata IntegrationExample of three-data-layer intersection attribute table

Task: Testifythe correctness

of derivedfeature

combinations in the polygon description.





Controlled two-by-two integrationusing geodata intersection.

1. Reference layer selected.

2. Synergetic layer ovelaid andcleaned.

3. (In)dependent layer overlaidand cleaned.

Landscape ecological approach





Terrain is the obligatoryreference layer.

Geology is the best thematicreference layer because of its

conservatism.

Geology polygon outlines have to befirst carefully adopted to terrain

represented by contourlines or DTM.





overlay + snapping

Cleaned geology according to terrain as thefirst thematic

reference layer.

Integration guide: real relationshipsbetween geology and soils in landscape.




Thematic (analytic) Geodata IntegrationOverlaid polygon outlines

snapping to avoid number ofremnant polygons. Overlaid

layer polygon outlines have to be snapped to approximately

paralel reference layer polygon outlines.

After the snapping the overlaidlayer to the reference layer, the

intersection of layer can becarried out.




Thematic (analytic) Geodata IntegrationIntegrated geology and soil layers Another analytic layer to be intersected

Addiotional overlaid layer first to be snapped




Thematic (analytic) Geodata IntegrationGeoprocessing completed: overlaid,

snapped and intersected data layers are represented in the attribute table by real

feature combinations only.

Efficient application ofGIS technology and

geographical knowledgefor the compilation ofbetter data sets for

various utilising.

geoprocessing in gis from geodata acquisition to...

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