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| PRACTICAL WORK ARC VIEW SOFTWARE PART 1 |
GENERAL PRESENTATION ARC VIEW SOFTWARE
ArcView:
-GIS office software created by ESRI (Environmental Systems Research Institute) allowing:- Creation, import, the opening of spatial data_
- Geometric and semantic correction
- Spatial and thematic analyses
- On-screen visualization; layout and printing
- Theme: equivalent to a layer in generic GIS term
- Entity: geometric shape characterized by its geographical position used to model an object.
- Entity types: - Points - Polyline - Polygons
Data sources that can be used in ArcView:
- Shapefile (shapefile : *.SHP)
- ArcInfo Coverage
- DXF file
- DGN file
- IMAGE file (TIF, JPG,...)
Table: Information presented in row and column form
- Line = entity = record
- Column = value of a characteristic or attribute = fields
Shapefile:
- *.shp records geometric entities
- *.shx records the index of geometric entities
- *.dbf Dbase file that saves the information
Project:
text file with extension *.APR which records an ArcView session
Extension:
additional programs to exploit specific GIS functionalities:
- Extension delivered as standard
- The optional extension (sold separately)
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I - DATA ACQUISITION:
- Use of already existing data e.g.: FTM DB
- Use of data in the form of a table containing GPS coordinates, rectangular coordinates (event table or location table)
- Scanning from a table to be digitized
- On-screen scanning on image background: scanned map, satellite image or orthophoto Note: Using the transform.avx extension to fix the scanned image
- Data import (ex: ArcInfo,MapInfo,DXF,DGN,...)
II - DATA STRUCTURING
- Field creation
- Deleting fields
- Entering and changing values
III - TABLE JOINTS
Join between attribute table and database, join keyIV - ANALYSES
A - SPATIAL :
- Select on a view: - with the mouse- By a polygon
- Selection using spatial relationships (select by theme)
- Proximity analysis (Buffer creation): buffer zone, influence zone (at a constant distance or according to the values in a field)
- Use of geographical processes (Geoprocessing):
- Dissolve
- Merge
- Clip
- Intersect
- Union
- Assign data by location
B - THEMATIC
- Selection using the semantic property of the entities of a theme (use of the query generator)
- Statistics on numerical attributes (statistics)
- Thematic map = how to display a theme
Types:
- Single symbol
- Unique value
- Graduated color
- Graduated symbol
- Chart
ArcView Details
The documents of a project:
(1) : "View": to display the geometry of a theme and manipulate the geometric shapes(2) : "Tables": for handling tabular data and dbf files opened in ArcView
NB: Here the "View" document is active
(3) : "Charts": for the creation of diagrams concerning numerical attributes
(4) : "Layouts": for creating and formatting the layout for printing
(5) : "Scripts": to write programs in "Avenue" language
(2), (3), (4) can be opened either from "project" or in "View
The "View" window
Menus and Toolbars
(7) : Button bar and (8): Toolbar
(9) : Table of contents of the themes
(10) : Status bar
Elements of the toolbar
(11) : to save the ArcView session in a project(12) : to add a theme in a view
(13) : to display the property of ONE active theme
(14) : to change the symbolization of ONE active theme
(15) : to display the attribute table of ONE active theme
(16) : to search for an attribute value containing a set of characters entered via a dialog box
(17) : query builder
(18) : button for managing the map display area
(19) : deselect all
(20) : to query information about an entity clicked on the display window
(21) : pointer
(22) : to display the vertices
(23) : to select geometric entities
(24) : display area management tool
(25) : distance measurement
(26) : HotLink link
(27) : to fit in with the area of interest
(28) : Individual label (attribute display)
(29) : Writing in graphic form
(30) : Creation of geometric shape, in the graphic form if no modifiable theme
the geometric entity in the active theme if it can be modified
(31) : Scale
(32) : Contact details
ArcView Theme
(33) : The theme (Cntry92.shp)(34) : if the box is checked the theme is visible, otherwise, it is not
(35) : the theme is active if its name is raised on the table of contents
NB :
* to be able to work on a theme (change the property, change symbols, etc.), it must be active
* Do not confuse visible theme with active theme
Adding a theme
- menu "View" >> "Add Theme" or click on (12)
- Click on (40) the drive on (39), choose the working directory that appears on (36)
- Choose from (38): "Feature Data Source" for a vector theme"Image Data Source" for a raster theme
- Choose the useful file in (37)
- Click on OK to finish
- For images, TIF files can be opened automatically. These files have a TFW header.
- On the other hand, JPG files require the loading of the "JPEG (JIFF) Image Reader" extension
Property of a view
- It is important to change "Map Units" and "Distance Units":
To be able to enter the scale in (31)
Some operations requiring distance measurements such as buffer zones are impossible.
- To avoid confusion, it is sometimes useful to change the name of the view
- (46) Changing the projection is useful if you have data in geographical coordinates. But when the data are already projected (such as the FTM databases), it is sufficient to change the units to the database unit (meters for BD500, BD100, BD200, BD10).
Symbolization of data
double-click on the name of the theme
Or make the theme active and click on (14)
By scrolling through the menu (50): "Legend type" we have:
PRACTICAL WORK ARC VIEW SOFTWARE PART 2
ArcView gis
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