Archive for December, 2007

Import Google Earth KML Files to ESRI Geodatabase with Arc2Earth

Posted on December 17, 2007. Filed under: Arc2Earth, ESRI, Google Earth |

Arc2Earth was initially created as a tool for exporting your existing ArcGIS data to Google Earth, but has since evolved into a robust tool that is also capable of importing KML/KMZ, GeoRSS, and Atom files into an ESRI geodatabase format.  With the release of Arc2Earth version 2, the data import functionality has been rewritten to be more flexible, and includes the ability to import KML/KMZ, GeoRSS (simple, GML), and geo-enabled AtomPub files. The import process can create a new feature class to store the data or update an existing feature class in a personal or enterprise ArcSDE geodatabase.

Click here to see a demonstration of using Arc2Earth to import an existing KML/KMZ file into an ESRI geodatabase. 


The “Import KML/KMZ” and “Import GeoRss/Atom” items on the Import menu item open the same Import KML dialog.  The General tab contains a number of options related to the file that will be imported as well as the geodatabase export parameters.  By default, the Import KML dialog is assumed to be KML.  If the importer can’t discern the file type of the source document you will need to know the feed type (GeoRss, Atom) and check the option indicating the file is of type GeoRss if necessary. In the event that you need to import all files in a folder you may specify a folder by using the browse button.  The target layer for your import can be stored in a personal or enterprise ArcSDE geodatabase and can be an existing or new feature class.  In the event that you will be storing the target layer in an ArcSDE enterprise database you must specify the correct connection string for the database.  Three feature classes are created, one each for points, lines, and polygons with the root name of each feature class defaulting to the KML/KMZ file name along with an extension of _points, _lines, or _polys.



Import options can be saved into an import file (*.a2ei) for later use for commonly used import operations by clicking the “Save” button and specifying a filename and directory path. Both import menu items open the same window, but different options are set for each type of import.


The Schema tab on the Import KML dialog contains options for importing KML extended data values, a description templates schema, and the option to only import placemarks.  The “Description Templates Schema” option can be used to pull attribute data from existing description tags in KML Placemarks.  Normally description tags are free form text making them difficult to cull meaningful information.  Schemas allow you to define where in the description text your attribute data is hidden. The “Only Import Placemarks” option can be used to limit the import to only those Placemarks that match the filters on your Template Schemas and are good for targeting specific data in a large KML file.



The Options tab on the Import KML dialog contains some general options related to KML/KMZ files.  The “Update existing features using Placemark ID’s” option is used with a Placemark ID to find an existing record to update.  When exporting KML, you can specify which field to use for the Placemark ID.  The “Delete all records” option removes existing records from a feature class before the import takes place. This option is useful when you need to re-use a feature class.  In the event that you need to download data loaded in Network Links contained within a KML/KMZ file you can use the “Download all Network Links” option. This option follows nested Network Links and downloads all data associated with these Network Links.  The “Ground Overlays” option downloads all ground overlays in a KML/KMZ file as raster images, and you may specify a folder to place the downloaded images and associated world files.



Click here to see a demonstration of using Arc2Earth to import an existing KML/KMZ file into an ESRI geodatabase. 


For more detailed information on Arc2Earth, please see our new e-learning course.




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Replacing ArcIMS with Arc2Earth Publisher?

Posted on December 10, 2007. Filed under: Arc2Earth, Google Maps |

James Fee wrote about the “The Day ArcIMS Died” in an April 23rd blog entry on his Spatially Adjusted blog.  James argued that you might be better off saving the money, time, and effort you’re investing in ArcIMS and replace it with Arc2Earth.  As James mentioned, “By not being able to serve up tiles, ArcIMS is slow, outdated and ugly. Time to move on (and I say this with great regret because I’ve rolled out more ArcIMS sites than I can remember over the years).”  At a fraction of the cost of ArcIMS, Arc2Earth is an efficient way to publish your ArcGIS data into a simple web based application.  Arc2Earth is particularly well suited for organizations that want to provide online mapping functionality, but don’t have the hardware (servers), software budget for ArcIMS or ArcGIS Server, or technical capabilities to develop custom applications.  They simply want to provide online access to their maps and data without any hassle.  I’m not here to denigrate ArcIMS or any other ESRI product.  In its time, ArcIMS was certainly a force in the delivery of online mapping applications.  However, Arc2Earth provides an excellent, and in many ways a superior alternative to ArcIMS for some users.  For anyone unfamiliar with Arc2Earth please read our past entries for an overview of its capabilities.

In this post I’ll show you the mechanics of exporting your ArcGIS data to Google Maps or Microsoft Virtual Earth from Arc2Earth using Amazon S3 to store your output data.  This solution set is an excellent way for organizations to efficiently and inexpensively publish their ArcGIS data to an online mapping application.  Arc2Earth is an ArcGIS extension so you can use these tools directly inside ArcMap.  The diagram below gives you a visual depiction of the process of creating map tiles from ArcGIS data through the Map Tile Exporter and their ultimate destination inside an Arc2Earth generated Map Viewer. In this case the Google Maps viewer is used.  Click here to see a demonstration of this process.

The General tab (seen below) on the Map Tile Exporter includes options for naming your map, background color, map appearance, and image format. The map name should be unique across all maps and defaults to the name of the active data frame in ArcMap. Background options control the background color and transparency. The appearance options apply primarily to Google Maps and include parameters for including Google Maps base maps and hybrid maps along with an option for exporting map graphics. 


The Levels tab contains options and information concerning the various map levels that will be created. Map tiles will be created based on the format used by the particular mapping provider and consist of up to 22 levels with a Mercator World Projection applied. You can define a start and end level for your export, and Arc2Earth will export all levels between these two values. It is rare that you will need an application that needs all levels. Other options include an option for full extent export, the creation of debug tiles, and the creation of GE tiles and regions. Storage estimates are provided so that you can accurately gauge the storage requirements that will be necessary as a result of the output. Other options from this tab include the ability to define exclusion and inclusion masks, and a Restart option for Enterprise users.

An export mask is a polygon layer used during the export to limit the amount of geographic area processed. Masks are an important component in increasing the processing speed for large data exports. There are two types of masks that can be used during your export: exclusion and inclusion. All masks should be polygon layers.  An exclusion mask is a polygon layer used to exclude areas from the export process. Any map tile fully contained by any polygon in this mask is skipped during the export process.  An inclusion mask is the exact opposite of an exclusion mask in that only tiles that fall within this mask are exported. This process only checks tile chunks so polygons in this layer should be large enough to accommodate some extra overlay at the edges.

The Storage tab for the Map Tile Exporter is used to specify where your data will be exported, and can include local, remote web server, and Amazon S3 options. Local storage allows you to select a local directory on your computer. By default, map tiles will be stored in the My Documents\KML Documents\Export Data\<Your Map Name> folder. Remote storage can be to a local server or a web server. Local servers normally refer to a web server virtual directory. If you have an Amazon S3 account you can enter your access and secret keys. You will need to have an account through Amazon to use this option.

The Viewers tab can be used to decide which viewers to create for your map, and the options include Google Maps, Google Earth, and MS Virtual Earth. When selecting the Google Maps option you will need to enter the API key you were assigned when creating a Google Maps account.

Let’s take a look at a demonstration of this process.  Pretty impressive!

For more information on e-learning or instructor led courses provided by GeoSpatial Training Services please click here.

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Using Arc2Earth to Create 3D Google Earth Displays with ArcGIS Data

Posted on December 3, 2007. Filed under: Arc2Earth, Google Earth |

As I’ve mentioned in previous posts on Arc2Earth, one of my favorite functions is the ability to create 3D Google Earth displays using existing ArcGIS data.  The ability to visualize your ArcGIS data in a 3D display makes for stunning visualizations, but it can also help reveal and emphasize patterns in your data.  For example, in a previous post I described how we used a combination of ArcGIS Desktop along with the Spatial Analyst extension, Arc2Earth, and Google Earth to analyze crime patterns in Houston, Texas through the use of heat-maps and 3D display of various crime categories.

In this post we’re going to explore how you can use Arc2Earth to export your ArcGIS data as 3D extrusions.  One of the most visually appealing options in Arc2Earth is the ability to create 3D Google Earth extrusions from your ArcGIS data.  Clicking the Extrude Options button on the Layer tab brings up the Layer Extrude dialog which allows you to extrude a layer based on attribute values in your feature class, set specific values for all features, or use existing Z values of a layer.

Let’s take a closer look at the Layer Extrude dialog which is used to display vector data in three dimensions inside the Google Earth viewer. The Altitude Mode options allows you to set a value of absolute (based on sea level), relative (based on the current terrain level) which is the default, or clamped which is based on the current terrain level but clamped to the ground. In addition, you can extrude based on a number of options including Z values of a layer (if available), attribute values in a field (must be a numeric field), or a set value in meters for each feature. The visibility of extrusion walls can also be controlled through the “Show extrusion walls” checkbox. Finally, extrusion height can be calculated based on a percentage of all field values in relation to a minimum and maximum height in meters.

Now let’s examine the various options for performing 3D extrusion in Arc2Earth. As previously mentioned, you can extrude based on a number of options including Z values of a layer, attribute values in a field, or a set value in meters for each feature. Some ArcGIS layers already have valid Z values associated with their geometry data and are said to be “Z Aware”. In these cases it is possible to use the Z values associated with each feature as the value which will be extruded. Other methods of extrusion include the capability of extruding based on tabular attribute data for the layer. This uses numeric attribute fields to determine the height of extrusion. All data in this case is assumed to be in meters although feet can be selected as well. In addition, you can use the “Calculate Extrude height…..” check box to use a percentage of the min and max you enter to derive the extrude value. Finally, you can extrude each feature by a set value which you enter. This value is calculated in meters.

For more information about Arc2Earth please see our e-learning course “Arc2Earth for ArcGIS Users“.


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