vod do GIS

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Úvod do GIS. Marek Doršic, ArcGEO (marek.dorsic@arcgeo.sk) FMFI UK , 15 . 11 .20 11. Moderné informačné technológie. FMFI UK, Bratislava. Autor : Marek Dor šic. GIS DAY. s treda v treťom novembrov om týždni = 16. n ovember 2011. Čo je GIS. - PowerPoint PPT Presentation

Text of vod do GIS

Shaft Data Capture= 16. november 2011
Úvod do GIS
Moderné informané technológie
Opakujúce sa slová (proste, v podstate, e akoe,...)
Kontakt s publikom
Úvod do GIS
Moderné informané technológie
o je GIS
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Because the geographic database is the expensive and long-lived component of the GIS, data entry is an important consideration. ArcGIS integrates a variety of data types from a variety of sources, so it provides multiple data entry options. ArcGIS offers efficient data entry methods for automating paper maps and other nondigital data sources. To take advantage of the vast collection of geographically referenced data that already exists in digital format, ArcGIS provides the most comprehensive data conversion capability of any GIS on the market. ArcGIS software’s integrative capabilities also allow data to be shared with other applications without the need for conversion.
Úvod do GIS
Moderné informané technológie
You can represent geographic features in vector or raster format.
Vector data
The vector data model represents geographic features much the same way maps do—using points, lines, and areas. An x,y (Cartesian) coordinate system references real-world locations.
Raster data
Instead of representing features by their x,y coordinates, the raster data model assigns values to cells that cover coordinate locations. Raster format is well-suited to spatial analysis and is also appropriate for storing data collected in grid format. The amount of detail you can show for a particular feature depends on the size of the cells in the grid. This makes raster data inappropriate for applications where discrete boundaries must be known, such as parcel management.
Úvod do GIS
Moderné informané technológie
Dve reprezentácie výšky
Kadá línie uchováva jednu výškovú hodnotu
Raster: hodnoty výšky reprezentované ako bunky
Kadá bunka uchováva jednu výškovú hodnotu
Výška ako raster
Výška ako vektor
Úvod do GIS
Moderné informané technológie
Okresy s potom obyvateov viac ako 300,000
Introduction to ArcGIS I
Identifying specific features
One common type of GIS query is to determine what exists at a particular location. In this type of query, the user understands where the features of interest are but wants to know what characteristics are associated with them. This can be accomplished with GIS because the spatial features are linked to the descriptive characteristics.
Identifying features based on conditions
Another type of GIS query is to determine the locations that satisfy certain conditions. In this case, the user knows what characteristics are important and wants to find out where the features are that have those characteristics.
Úvod do GIS
Moderné informané technológie
Pórovitos Pórovitá
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You can perform analysis to obtain the answers to a particular question or find solutions to a particular problem. Geographic analysis usually involves more than one geographic dataset and requires the analyst to proceed through a series of steps to reach a result. Three common types of geographic analysis are:
Proximity analysis
How many houses lie within 100 meters of this water main?
What is the total number of customers within 10 kilometers of this store?
What proportion of the alfalfa crop is within 500 meters of the well?
To answer such questions, GIS technology uses a process called buffering to determine the proximity between features.
Overlay analysis
An overlay process combines the features of two layers to create a new layer that contains the attributes of both. This resulting layer can be analyzed to determine which features overlap or to find out how much of a feature is in one or more areas. An overlay could be done to combine soil and vegetation layers to calculate the area of a certain vegetation type on a specific type of soil.
Network analysis
This type of analysis examines how linear features are connected and how easily resources can flow through them.
Úvod do GIS
Moderné informané technológie
2-*
For many types of geographic operations, the end result is usually best visualized as a map or graph. Maps are efficient for storing and communicating geographic information. Cartographers have created maps for millennia, but GIS provides new and exciting tools to extend the art and science of cartography. Maps can be integrated with reports, three-dimensional (3D) views, photographic images, and other digital media. This topic is discussed in greater detail in Lesson 3.
Úvod do GIS
Moderné informané technológie
2-*
Sharing the results of your geographic labor is one of the primary justifications for investing resources in GIS. A powerful method for sharing displays created through a GIS is to output them into a distributable format. The more output options a GIS can offer, the greater the potential for reaching the right audience with the right information.
Úvod do GIS
Moderné informané technológie
Organizovanie priestorových dát
Odpovede na otázky dostávame v rôznych porovnávaním rôznych dátových vrstiev
Introduction to ArcGIS I
Organizing spatial data
A GIS organizes and stores information about the world as a collection of thematic layers that can be linked by geography. Each layer contains features with similar attributes, like streets and cities, that are located in the same geographic extent. This simple, but powerful and versatile, concept has proven invaluable for solving real-world problems from tracking delivery vehicles to modeling global atmospheric circulation.
The onion analogy
Think of the world as a large onion. When you peel an onion, you see that it is composed of many layers. Real-world entities can be seen the same way; the earth can be ‘peeled’ into many layers, each representing a different theme. For example, you can put all the streets in one layer and all the landuse areas in another layer. As you can imagine, the earth’s complexity allows you to create as many layers as you want. The question then becomes how to best organize these real-world entities into manageable geometric shapes (point, line, area) and store them digitally.
Úvod do GIS
Moderné informané technológie
Reálne prvky sveta sú abstrahované do troch základných typov geometrií
body
Maloobchody
línie
Ulice
polygóny
Abstracting real-world entities
It is impossible to capture everything from reality inside a computer. Instead, GIS users must somehow abstract real-world phenomena, or entities, into a geometric representation of those entities. There are three basic geometric shapes used for geographic features: points, lines, and areas. These shapes can be called geometric objects, geometric features, or feature types.
Note that there are different methods of making these entities digital, including scanning and digitizing.
Úvod do GIS
Moderné informané technológie
mesto
1:500
1:24000
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Map scale is an important but often misunderstood concept in cartography. To represent a portion of the earth’s surface on a map, the area must be reduced. The extent of this reduction is expressed as a ratio called map scale. Map scale is the ratio of map distance to ground distance.
For example, if you draw a 4.8-km road as a 20-cm line on your map, the following statements would describe the map scale:
20 cm : 4.8 km, 20 cm : 480,000 cm, 1 cm : 24,000 cm, 1 : 24,000
The latter is known as a representative fraction (RF) because the values on either side of the colon represent the proportion between distance on the map and distance on the ground; that is, “1:24,000” means “1 map inch represents 24,000 ground inches”, “1 map meter represents 24,000 ground meters”, or “1 map centimeter represents 24,000 ground centimeters”, and so on.
Map scale can be expressed in several different manners: as a fraction (1:24,000), as a verbal statement (one centimeter equals one kilometer), or as a bar.
Map scale indicates how much a given distance was reduced to be represented on a map. For maps with the same paper size, features on a small-scale map (1:1,000,000) look smaller than those of a large-scale map (1:1,200). In other words, a dime-sized lake on a large scale map (l:1,200) would be less than the size of the period at the end of this sentence on a small-scale map (1:1,000,000).
In general, small-scale maps depict large ground areas, but they have low spatial resolution, showing little detail. On the other hand, large-scale maps depict small ground areas but have high spatial resolution, showing many details. The features on large-scale maps more closely represent real-world features because the extent of reduction is lower than that of a small-scale map. As map scale decreases, features must be smoothed and simplified or not shown at all. For example, at a scale of 1:63,360 (in which 1 inch = 1 mile), it is difficult to represent area features smaller than 1/8th of a mile long or wide because they will be 1/8th of an inch long or wide on a map.
Úvod do GIS
Moderné informané technológie
Mapová projekcia je sada pravidiel pre to, kam transplantova lokácie
Existuje mnoho rozliných mapových projekcií
Mapové projekcie
Úvod do GIS
Moderné informané technológie
Projekcie vplývajú na skreslenie rôznymi spôsobmi
Niektoré zachovávajú jednu charakteristiku na úkor iných
Niektoré sú kompromisné pre všetky charakteristiky
Sú významné len pre mapy vemi vekých oblastí
Bez skreslenia
Skreslenie plochy
Skreslenie tvaru
Skreslenie vzdialenosti
a smeru
Kadý prvok odpovedá záznamu v atribútovej tabuke
Atribúty
Geometria
Správanie
Pravidlá:
Ulice
Attributes
Behavior
Behavior means geographic features can be made to follow certain types of editing, display, or analysis rules, depending on circumstances defined by the user.
Úvod do GIS
Moderné informané technológie
Pouívanie priestorových vzahov
Topológia matematicky modeluje spojitos, priahlos a koincidenciu
I-80 spája San Francisco a New York
San Francisco je obsiahnutý v Kalifornií
I-80 má dku a smer
New York je priahlý k Atlantickému Oceánu
Introduction to ArcGIS I
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The relationships between features on a map, or where they are located in space relative to one another, communicates important information. Connectivity, adjacency, and containment are types of spatial relationships shown in the graphic above. Interstate 80 connects San Francisco with New York City. San Francisco is adjacent to the Pacific Ocean, and California is within the USA. Features may also have coincidence; for example, California and Nevada are both separate polygons, yet each has a common boundary line in the exact same space as the other, these lines are seen to be coincident.
The spatial relationships between connecting, coincident, or adjacent features in a geographic data layer are often referred to as topologic relationships. Topology is the branch of geometry that deals with the properties of features that remain unchanged even when the features are bent, stretched, or otherwise distorted.
ArcGIS uses these spatial relationships and feature properties like area, length, and direction to identify complex spatial patterns.
Úvod do GIS
Moderné informané technológie
popisné, priestorové, atribútové a
spracovania
Formáty metadát
Introducing metadata
Often the definition given for metadata is ‘data about data’. While this definition is not incorrect, it is not very informative. More precisely, metadata supports descriptive information about data. Text written on the back of a photograph telling you the photograph’s date and subject and nutrition labels on food containers are common examples of everyday metadata. For spatial data, metadata includes descriptive information such as date, creator, geographic extent, coordinate system, and attribute domains. Metadata gives your data credibility, and in many situations, your data may be impossible to interpret or use without it.
The Metadata tab in ArcCatalog displays the metadata for a selected dataset. If metadata does not exist for the selected dataset, ArcCatalog creates as much metadata as it can from the existing information. For the FGDC ESRI stylesheet, the Metadata tab is divided into three categories, each with an active tab:
Description—contains the basic narrative information about the dataset, including source, organization, date, uses, and restrictions.
Spatial—contains the coordinate information and geographic extent of the dataset.
Attributes—includes fields, attribute domains, and related tabular information.
You can create, edit, import, and export the metadata for any given dataset. Because metadata information is stored in XML format, you can use it with other software that can read XML documents.
Úvod do GIS
Moderné informané technológie
Telekomunikácie
poskytovanie mapových podkladov
Úvod do GIS
Moderné informané technológie
Úvod do GIS
Moderné informané technológie
Úvod do GIS
Moderné informané technológie
dynamické zobrazovanie ponuky poda extentu, prepojenie s katastrom nehnuteností, vyhadanie trasy,
D
Úvod do GIS
Moderné informané technológie