Spatial and Attribute Data Management J M Piwowar

Spatial and Attribute Data Management © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Spatial and Attribute Data Management 1

Spatial Data Management § How does Arc. GIS store its files? © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Spatial and Attribute Data Management 2

v A very common format for spatial data files. v Only for vector data. © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Spatial and Attribute Data Management 3 Carlson, Lynn, “Understanding Geospatial Data Files used in Geographic Information System Software: A Basic Introduction”. http: //gisatbrown. typepad. com/gis/files/spatialdatafiles. pdf. Accessed 2007. 01. 15 Shapefiles

v An old Arc/Info file format. v Only for vector data. © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Spatial and Attribute Data Management 4 Carlson, Lynn, “Understanding Geospatial Data Files used in Geographic Information System Software: A Basic Introduction”. http: //gisatbrown. typepad. com/gis/files/spatialdatafiles. pdf. Accessed 2007. 01. 15 Coverages

v An old Arc/Info file format. v Only for raster data. © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Spatial and Attribute Data Management 5 Carlson, Lynn, “Understanding Geospatial Data Files used in Geographic Information System Software: A Basic Introduction”. http: //gisatbrown. typepad. com/gis/files/spatialdatafiles. pdf. Accessed 2007. 01. 15 Grids

v The Geodatabase (GDB) is the newest ESRI file format. v Advantages: Ø Ø Ø © J. M. Piwowar All your data is contained in a single file (*. gdb). Can hold raster and vector data. Can enforce topology rules (e. g. to prevent features from overlapping that aren’t supposed to). Geog 409: Advanced Spatial Analysis & Modelling Spatial and Attribute Data Management 6 Carlson, Lynn, “Understanding Geospatial Data Files used in Geographic Information System Software: A Basic Introduction”. http: //gisatbrown. typepad. com/gis/files/spatialdatafiles. pdf. Accessed 2007. 01. 15 Geodatabases

§ Keep The Names Short v v § Do Not Use Spaces v v § e. g. town#boundaries is a bad name for a file e. g. my!gis!data is a bad name for a folder Never Put A Number As The First Character v v § town boundaries is a bad name for a file; use town_boundaries instead my gis data is a bad name for a folder that will contain spatial data files; use my_gis_data instead Do Not Use Special Characters (the only exception is the underscore) v v § Between 8 and 15 characters If you work with spatial data that are in the “coverage” vector format, or the “grid” raster format, only 8 characters are allowed. e. g. 2000 population is a bad name for a file a good alternative would be y 2000 pop Keep The Names Simple v v use abbreviations where possible use underscores where possible as a replacement for spaces use upper case where it makes sense e. g. twn_bndy or Twn. Bndy © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Spatial and Attribute Data Management 7 Carlson, Lynn, “Understanding Geospatial Data Files used in Geographic Information System Software: A Basic Introduction ”. http: //gisatbrown. typepad. com/gis/files/spatialdatafiles. pdf. Accessed 2007. 01. 15 File Naming Guidelines

§ Implement A Tracking Method v When you begin to perform analysis, you will frequently be generating a copies of the data that have “added value”. v Therefore, it is important that you have a naming convention that will allow you to keep track of these sequential files. v Example: you may start with a shapefile of town_boundaries which only has one attribute (e. g. the name of the town). Performing a process called a Join results in new attributes (population of each town, zip code, the number of grocery stores in each town, etc) being appended to the table. v Once the join is completed, you would export the entire file to a new file (e. g. town_boundaries_2) in order to permanently retain the new attributes. v Because you have implemented a tracking method it will be easy to distinguish the latest file you are working with. © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Spatial and Attribute Data Management 8 Carlson, Lynn, “Understanding Geospatial Data Files used in Geographic Information System Software: A Basic Introduction ”. http: //gisatbrown. typepad. com/gis/files/spatialdatafiles. pdf. Accessed 2007. 01. 15 File Naming Guidelines