Vector data, attribute queries, spatial queries

Spatial data is any type of data that directly or indirectly references a specific geographical area or location. A location can be represented not only by a combination of coordinates (X + Y, latitude + longitude, etc.), but also by, for example, an address (of arbitrary detail). The two most common data formats used to store (geo)spatial data are vector and raster.

Spatial data types

• Vector data

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  • represent elements of the real world using basic geometric elements: points, lines and surfaces (called polygons)

  • the detail of the data is determined by the detail of the coordinates of the vertices of the geometric feature

  • suitable for modelling and analysis of discrete objects (e.g. location of points, land cover categories)

  • suitable for map creation, length measurements, geometric calculations

  • possible problems with topology (gaps and overlaps)

  • basic vector data formats are Esri Shapefile, GeoJSON, GeoPackage or KML/GML

• Raster data

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  • represent real world elements in the form of a regular grid made up of pixels (from picture element)

  • the detail of the data is determined by the spatial resolution of the grid, i.e. the size of the pixel edge (in meters)

  • suitable for modeling and analysis of continuous phenomena (elevation, temperature, precipitation)

  • used for image data (e.g. satellite imagery)

  • raster datasets can become potentially very large

  • basic raster data formats are GeoTIFF, JPEG, PNG or GIF

Difference in graphical representation of vector and raster data (Geletič et al. 2019)

Contents

Attribute queries

Attribute Query is a method of selecting/filtering elements based on attribute values. It complements the interactive feature selection method from practical 1. The basis is a selection rule - called Expression. ArcGIS Pro allows you to build expressions interactively using a dialog, but to use the full potential of expressions, it is recommended to use SQL code.

Attribute query (over map data): Map → Select By Attributes → fill in the dialog... Select features using attributes

The Input Rows field is automatically prepopulated with the layer selected in the map content

Using the you can change the notation between the interactive dialog entry and the SQL expression.

Introduction to query expressions Construct and modify queries

Example to try

testing attribute queries on real data

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Layer attributes scheme:

attribute	data type	description
FEATURECLA	String	Populated places classification
NAME	String	Name of the populated place
WORLDCITY	Integer	Whether the place is classified as a World city, 0=no, 1=yes
MEGACITY	Integer	Whether the place is classified as a Mega city, 0=no, 1=yes
SOV0NAME	String	Name of the sovereign country
ADM0NAME	String	Name of the admin country
ADM1NAME	String	Name of the First-level administrative devision in a country
LATITUDE	Double	Latitude
LONGITUDE	Double	Longitude
POP_MAX	Double	Estimate of inhabitants of the place with urban agglomeration
POP_MIN	Double	Estimate of inhabitants of the place without urban agglomeration
TIMEZONE	String	Name of the timezone

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Spatial queries

Spatial Query is a method of selecting/filtering elements of one layer based on their relative position with elements of another layer. The function uses as input the layer of selected elements, the layer for overlay analysis a the relationship for overlay analysis.

Select POINTS...Select LINES...Select POLYGONS...

...using POINTS...using LINES...using POLYGONS

Intersect	A
Intersect (DBMS)	A
Contains	A
Contains Clementini	A
Within	A
Within Clementini	A
Are identical to	A
Have their center in	A

Intersect	A, C
Intersect (DBMS)	A, C
Within	A, C
Completely within	A
Within Clementini	A
Have their center in	A, C
Boundary touches	C

Intersect	A, C
Intersect (DBMS)	A, C
Within	A, C
Completely within	A
Within Clementini	A
Have their center in	A, C
Boundary touches	C

...using POINTS...using LINES...using POLYGONS

Intersect	A, C, D
Intersect (DBMS)	A, C, D
Contains	A, C, D
Completely contains	A, D
Contains Clementini	A, D
Have their center in	D
Boundary touches	C

Intersect	A, C, D, E, F, G, H, I, J
Intersect (DBMS)	A, C, D, E, F, G, H, I, J
Contains	G, H
Completely contains	G
Contains Clementini	G, H
Within	F, H
Completely within	F
Within Clementini	F, H
Are identical to	H
Boundary touches	C, E
Share a line segment with	F, G, H, I, J

Intersect	A, C, D, E, F, G, H, I, J, K, L, M, N, O
Intersect (DBMS)	A, C, D, E, F, G, H, I, J, K, L, M, N, O
Within	A, D, G, H, I, O
Completely within	A
Within Clementini	A, D, G, H, I
Boundary touches	F, G, H, I, K, L, M, N, O
Share a line segment with	G, I, J, K, M, O
Crossed by the outline of	C, E, H, L, N
Have their center in	A, C, D, E, G, H, I, J, O

...using POINTS...using LINES...using POLYGONS

Intersect	A, B
Intersect (DBMS)	A, B
Contains	A, B
Completely contains	A
Contains Clementini	A
Have their center in	A, D
Boundary touches	B

Intersect	A, C, D, E, F, G, H, I, J, K, L, M, N, O
Intersect (DBMS)	A, C, D, E, F, G, H, I, J, K, L, M, N, O
Contains	A, D, G, H, I, O
Completely contains	A
Contains Clementini	A, D, G, H, I
Boundary touches	F, G, H, I, K, L, M, N, O
Share a line segment with	G, I, J, K, M, O
Crossed by the outline of	C, E, H, L, N
Have their center in	E, I, L

Intersect	A, C, D, E, F, G, H, I, J, K, M
Intersect (DBMS)	A, C, D, E, F, G, H, I, J, K, M
Contains	C, E, H, M
Completely contains	C
Contains Clementini	C, E, H, M
Within	F, G, H, M
Completely within	F
Within Clementini	F, G, H, M
Are identical to	H, M
Boundary touches	D, E, G, H, I, J, M
Share a line segment with	D, H, I, M
Crossed by the outline of	A, E, G, J, K
Have their center in	C, E, F, G, H, K, L

Select features by location Select Layer By Location (Data Management) Select By Location graphic examples