Editing Content :: Admin Scraper

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SequenceofGISActivities The following sequence of the activities are involved in GIS-related work : 1. Spatial data input 2. Entering of the attribute data 3. Data verification and editing 4. Spatial and attribute data linkages 5. Spatial analysis Spatial Data Input As already mentioned, the spatial database into a GIS can be created from a variety sources. These could be summarised into the following two categories : (a) Acquiring Digital Data sets from a Data Supplies The present day data supplies make the digital data readily available, which rangefromsmall-scalemapstothelarge-scaleplans. Formanylocalgovernments and private organisations, such data form an essential source and keep such groups of users free from overheads of digitising or collecting their own data. Although, using such existing data sets is attractive and time saving, serious attention must be paid to data compatibility when data from different sources/ supplies are combined in one project. The differences in terms of projection, scale, base level and description in attributes may cause problems. At a practical level, users must consider the following characteristics of the data to ensure that they are compatible with the application: • The scale of the data • The geo-referencing system used • The data collection techniques and sampling strategy used • The quality of data collected 53 • The data classification and interpolation methods used • The size and shape of the individual mapping units S t • The length of the record. a It must also be noted that where data are used from a number of sources, I and particularly where the area of study crosses administrative boundaries, the f difficulties in data integration are caused by different geographical referencing m systems, data classification and sampling. Hence, the user needs to be aware of a o these problems, which are particularly prone when compiling inter-province, n and inter-district data sets. Once, the compatibility between the data acquired c from different suppliers is established, the next stage involves the transfer of n data from a medium of transfer to the GIS. The use of DAT tapes, CD ROMS and o floppy disks is becoming increasingly common for the purpose. At this stage, the y conversion from encoding and structuring system of the source to that of GIS to be used is important. (b) Creating digital data sets by manual input The manual input of data to a GIS involves four main stages : • Entering the spatial data. • Entering the attribute data. • Spatial and attribute data verification and editing. • Where necessary, linking the spatial to the attribute data. Reprint 2026-27