Browse through our answers to frequently asked questions; if you can’t find the answer you need, contact us!
What are geospatial data?
- of or relating to the relative position of things on the earth’s surface
- pertaining to the geographic location and characteristics of natural or constructed features and boundaries on, above, or below the earth’s surface; especially referring to data that is geographic or spatial in nature.
Definition source: Dictionary.com (last date accessed: 6 August 2017)
All data available for download from RIGIS is tied to real locations throughout the state of Rhode Island, and represent either natural or man made features that can be found within our state. Some of the data available for download also represent what could happen sometime in the future; the scaled Sea Level Rise data is a great example of this type of “predictive” geospatial data.
If I have a question about a specific dataset, who should I contact first?
For questions pertaining to specific datasets, please first contact the Point of Contact (PoC) listed in the metadata record under the “Identification Information” section for that dataset. The person listed as the PoC will have the most comprehensive knowledge about that dataset.
Alternatively, please feel free to contact Greg Bonynge, the RIGIS Data Manager, at email@example.com or at 401-874-2180 with any questions, comments or concerns.
What projection can I download data in?
All vector data is downloadable, by default, in WGS 1984; all vector datasets can also be downloaded in the RIGIS native Rhode Island State Plane (feet) North American Datum 1983 projected coordinate system. This option is available at the very bottom of a datasets “Download Data” drop down menu.
All tiled raster data, such as aerial imagery, US Topo Maps, or elevation data, can be downloaded only in the Rhode Island State Plane (feet) North American Datum 1983 projected coordinate system.
All raster datasets, such as impervious surfaces and soil erosion, can be downloaded only in the Rhode Island State Plane (feet) North American Datum 1983 projected coordinate system.
What are the horizontal units of the data I downloaded?
All vector data downloaded in WGS 1984 has units of meters. All vector datasets downloaded in the Rhode Island State Plane (feet) North American Datum 1983 projected coordinate system has units of feet.
All tiled raster data, such as aerial imagery, US Topo Maps, or elevation data, are downloaded with units of feet.
All raster datasets, such as impervious surfaces and soil erosion, are downloaded with units of feet.
Are parcel data available on RIGIS?
No, parcel data requests must be made directly to the municipality in question. Select the appropriate municipality from our Municipal GIS Resources page.
Are voting districts (precincts) available on RIGIS?
At this time, no municipal voting district or precinct data are available via RIGIS.
Those who are interested in obtaining these data must contact each municipality individually with such requests. For a list of options on accessing municipal data, please reference the parcel FAQ.
What are all of those files contained within a shapefile (.SHP) zip?
An ArcMap Shapefile (SHP) consists of 6-8 different individual files (.cpg, .dbf, .prj, . sbn, .sbx, .shp, .shx, .xml). These will all have the same file name and need to be located with the Shapefile in the same directory.
- .shp: the feature geometry - .shx: a positional index of the feature geometry contained with the .shp - .dbf: attribute information
- .prj: coordinate system and projection information - .sbn & .sbx: a spatial index of features - .cpg: used in conjunction with the .dbf - .xml: metadata, usually in the FGDC metadata format, although there are other formats
What is a .ZIP file?
A .ZIP file is a compressed binary file format that utilizes lossless data compression. .ZIP files were developed to expedite file transfers, and to serve as an archive file format. A .ZIP file will contain one or more individual files within it.
How can I stay up-to-date on happenings in the RIGIS user community?
There are a few ways to stay up to date with the RIGIS user community!
- Join our email listserv RIGIS-L – this is great way to stay in touch with happenings within the RIGIS user community.
- Follow us on Twitter at @RIGIS
How do I access map & image services featuring RIGIS data through ArcMap?
To access Map & Image services in ArcMap, follow the following instructions:
1) Click the arrow next to the Add Data button to expand the menu. 2) Select Add Data from ArcGIS Online…
3) In the search bar, type in RIGIS. This will display all available map and image services hosted by the University of Rhode Island Environmental Data Center. To get more details about an item, click Details; to add to your ArcMap document, click Add.
NOTE: Services containing authoritative RIGIS data will be posted by the account URIEDC_RIGIS. Please look for this when selecting data.
Can I connect to RIGIS services via an ArcGIS Server Connection?
Yes, you can! Follow the instructions below to establish a connection with RIGIS services.
First, open ArcCatalog and scroll down to the “GIS Servers” area of your Catalog Tree. Double click on “Add ArcGIS Server”; within the dialog box that opens, select the option to “Use GIS Services”. On the next dialog, copy and paste in the following link – https://maps.edc.uri.edu/arcgis – into the line for Server URL and click “Finish”.
This is a great way to connect to RI Digital Atlas map services featuring RIGIS data.
How do I efficiently download many tiles of data?
To download imagery in bulk, utilize a bulk download tool such as DownloadThemAll!
How do you recommend citing data obtained from RIGIS within an academic paper or professional report?
Use of a professional or academic publication standard is encouraged.
Use this format as an example of a citation for an individual RIGIS dataset:
RIGIS, 2017. Rhode Island Senate Districts; senateDist13r2. Rhode Island Geographic Information System (RIGIS) Data Distribution System, URL: http://www.rigis.org, Environmental Data Center, University of Rhode Island, Kingston, Rhode Island (last date accessed: 10 April 2017).
And a citation for the collective RIGIS online database might be:
RIGIS, 2017. Rhode Island Geographic Information System (RIGIS) Data Distribution System. URL: http://www.rigis.org, Environmental Data Center, University of Rhode Island, Kingston, Rhode Island (last date accessed: 10 April 2017).
Can I get official RIGIS logos to use on my maps?
Drop by the RIGIS Logo Depot!
How do I view MrSID images?
MrSID (Multiresolution Seamless Image Database; *.sid) is a proprietary image format owned by LizardTech. This format is known for its capacity to greatly reduce (compress) image file sizes, with only minor sacrifices to image quality when compared to the traditional GeoTIFF format.
After downloading a MrSID formatted image from RIGIS, you may need to install some software to view the file. If you are not a GIS user, our recommended viewer is either GeoViewer (standalone software for Windows) or the ExpressView Browser Plug-in for Windows, or GeoViewer for iOS, both available from LizardTech. These software perform well, and also may be used to view the MrSID compressed images RIGIS distributes.
Please email us if you find other useful, free software that display MrSID formatted images!
Users are encouraged to explore the offerings available in the RI Digital Atlas; this online atlas hosts viewable web maps of all our historical imagery collections (and much more!). Using the services provided by the RI Digital Atlas is a great way to incorporate historical imagery into your ArcGIS Online or ArcMap document.
What is the difference between a GeoTIFF and a JPEG2000 (JP2)?
A GeoTIFF is a lossless geospatial file format, typically resulting in large file sizes.
A JPEG2000 (JP2) is a geospatial file format available as either lossy or lossless, and offers highly compressed file sizes.