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Tips and Tricks for linking data in ArcGIS

There are two basic types of joins in GIS tables and geo-data: spatial and relational (based on table IDs). Spatial join is the key concept in GIS and that is what sets all GIS technologies apart from other relational databases. Here we start with performing relational joint of list of zipcodes with names to the US zipcode shapefile.

Relational Join

To join table to shapefile based on ID (zipcode) the data type in the column you are planning to join should be the same. Let’s check on data type in Zip code shapefile. Right click on shapefile, select properties and look under Fields tab. The format of the data is Text and size is 5 digits.

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Converting multiple KML files into geodatabase for GIS project in ArcMap Desktop

Google Earth is wide-spread free GIS application which allows users to draw their own point, lines and polygons. Very often users create many separate files in KML or KMZ format and upon moving to the next step in GIS analysis are trying to recreate the same geographies in ArcGIS editing software. The fastest way to bring all those custom data into GIS project is described here. Assuming that you have Google Earth and ArcGIS Desktop 10.2 installed, bring all the KML/KMZ files into Google Earth through File\Open (you can select multiple files from the same folder):

Building geodatabase in ArcMap 10 Desktop

Those step-by-step tutorials are created for novices in GIS. By design, they are very simple and provide only essential and practical information to accomplish most common tasks with GIS software. For in-depth coverage of the topic, please, refer to ESRI ArcGIS Resources http://resources.arcgis.com/en/help/main/10.1/

The three primary types of datasets in GIS

Geodatabase can incorporate links to the non-spatial databases, shapefiles, images, etc. A key geodatabase concept is the dataset. It is the primary mechanism used to organize and use geographic information in ArcGIS. The geodatabase contains three primary dataset types:

  • Feature classes
  • Raster datasets
  • Tables

Creating a collection of these dataset types is the first step in designing and building a geodatabase. Users typically start by building a number of these fundamental dataset types. Then they add to or extend their geodatabases with more advanced capabilities (such as by adding topologies, networks, or subtypes) to model GIS behavior, maintain data integrity, and work with an important set of spatial relationships.

Geodatabase elements

All GIS users will work with three fundamental dataset types regardless of the system they use. They'll have a set of feature classes (much like a folder full of Esri shapefiles); they'll have a number of attribute tables (dBase files, Microsoft Access tables, Excel spreadsheets, DBMSs, and so forth); and most of the time, they'll also have a large set of imagery and raster datasets to work with.

Fundamentally, all geodatabases will contain this same kind of content. This collection of datasets can be thought of as the universal starting point for your GIS database design.

Importing KMZ/KML data into ArcMap and creating shapefile

Very often your collaborators/scouts send you their geographical data (points, lines, polygons) in KMZ/KML format as GoogleEarth application is freeware and readily available. In order to do GIS analysis on such data and incorporate them into your ArcMap project you will need to import such data into ArcMap.

1. Make sure you received KML and not KMZ (zipped KML package) data. If you received KMZ, open the file in Google Earth first and save as KML. Refer to this blog post for detail instructions. Note: You might try to work on KMZ directly in ArcMap, I confirmed that ArcMap 10.2 can import point data from KMZ file, but previous version and other data (lines, polygons) had given me problems in the past when I tried importing from KMZ directly.

2. Start ArcMap (new project or any project covering the area your data are coming from). Open ArcToolBox (click on the red toolbox icon on the top). In Conversion Tool/From KML start KML To Layer.

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Performing spatial joint in ArcMap: points to polygons

1. Bring polygon dataset to ArcMap – can be shapefile from the local drive.

2. Bring CSV or Excel table with Lat Long for points:

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3. Right click the CSV file and export data as shapefile (creates a shapefile from table data).

Extracting Geographical Lat-Long data from Google Earth KML / KMZ files to Excel

If you have some data in table format with IDs for fields or point locations on the map and Google Earth KML file with those fields having same IDs, it is generally possible to bring spatial information to Excel and merge those data sources together to use in further spatial analysis in other GIS software and in newly released FREE ESRI Maps for MS Office Beta 2. There are a few little tricks to it, though…

Google Earth KML files are essentially XML files with geographical information, but Excel will not open them directly.

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Adding Lat-Long for the centroids of USA counties in a new point shapefile (ArcMap 10)

Software: ArcGIS - ArcEditor 9.2, 9.3, 9.3.1, 10 ArcGIS - ArcInfo 9.2, 9.3, 9.3.1, 10 ArcGIS - ArcView 9.2, 9.3, 9.3.1, 10 ArcGIS for Desktop Advanced 10.1 ArcGIS for Desktop Standard 10.1

USA counties center pointsThis is documented step-by-step and hands-on exercise on how to create XY point shapefile for the centers of USA counties (with linked basic demography and FIPS) in ArcMap 10.1. You don’t need to follow those steps (and if you don’t have ArcGIS for Desktop, you cannot) and may just grab the resulted layer file in various formats at the end of this post. Formats available are MS Excel table, CSV table with XY, zipped SHP file package, and KMZ file.

This layer is not directly shareable on ArcGIS Online, as it has more than 1000 features (3143, to be exact), we may post it there later as partial files…

If you need help with your GIS project, please, do not hesitate to contact Landviser, LLC - post comment, email info@landviser.com, or call 609-412-0555. Current complete catalog of Landviser LLC

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