A raster image, also called a bitmap, is a way to represent digital images.It can be created in a wide variety of formats, including the familiar.gif,.jpg, and.bmp. The image is represented in a series of bits of information that translate into pixels on the scr. The raster below displays elevation—using green to show lower elevation and red, pink, and white cells to show higher elevations. Rasters as thematic maps. Rasters representing thematic data can be derived from analyzing other data. A common analysis application is classifying a. Raster images are the preferred method when working with photographs. When photos are taken with a digital camera or copied on a scanner, the resulting files are raster images. Almost all of the images you find on websites are raster images, even those that may have originally been created with paths. Raster data is simple yet heavy to handle due to toa large amount of imagery related files. Unlike earlier days, RDMS and Systems have become robust to handle these large and heavy data models. Both the data types are crucial in the world of GIS, but Raster data is the most preferred one. Recommended Articles. This is a guide to Raster Data.
Origin of raster
- German from Latin rāstrumrake (from the resemblance of the parallel lines to a rake's path)rēd- in Indo-European roots
From American Heritage Dictionary of the English Language, 5th Edition
- From GermanRaster, from Latinraster, from rastrum (“a rake'), from verb radere (“to scrape').
From Wiktionary
NOAA offers raster chart products in a variety of formats
How to transition from traditional NOAA paper nautical charts to ENC-based products, including paper NOAA Custom Charts.
End of Traditional Paper Charts - In November 2019, NOAA initiated a five-year process to end all raster nautical chart production, including the five traditional paper chart products described on this webpage and within the expandable blue bars below. NOAA is intent on easing the transition to ENC-based products while continuing to support safe navigation. This includes improving data consistency and providing larger scale coverage for the electronic navigational chart (NOAA ENC®).
New Paper Chart Product - NOAA is aware that some chart users prefer paper charts. Although production of traditional paper charts will stop, a new form of paper nautical chart will be available through the NOAA Custom Chart capability (currently in prototype form). This system will enable users to create, customize, and print paper charts themselves, or have large format charts printed and delivered by a NOAA certified print-on-demand (POD) chart agent. We encourage those who want to continue using paper charts to become familiar with the NOAA Custom Chart prototype and let us know how to improve the system.
These documents provide more details about the sunsetting of NOAA raster/paper charts, ongoing improvements to NOAA’s premier electronic navigational chart product, and NOAA Custom Charts.
- Initial NOAA announcement to end production of traditional paper nautical charts – November 2019
- Sunsetting Traditional Paper Charts – Explains the sunsetting process, rationale, and affected products.
- Transforming the NOAA ENC® – Provides more information about ENC improvements.
- NOAA Nav-cast: How to obtain ENC-based paper nautical charts after NOAA ends production of traditional paper charts? – Recorded presentation that (1) discusses the decision and timeline to sunset raster charts, and (2) provides a demonstration of the NOAA Custom Chart prototype.
Five Raster Chart Products
NOAA produces raster charts in five formats:
- Paper nautical chart
- Full-size nautical chart
- Booklet Chart™
- Raster navigational chart (RNC)
- RNC Tile Service
Common Features of all NOAA Raster Charts, Including Paper Charts
Just as NOAA electronic navigational chart (NOAA ENC®) cells do, all raster charts portray water depths, coastlines, dangers, aids to navigation, landmarks, bottom characteristics and other features, as well as regulatory, tide, and other information. All raster chart products are based on and have the same appearance as the “traditional” paper charts that Coast Survey has provided for U.S. waters since the early 19th century.
They contain all critical corrections published in notices to mariners since the last new edition of the chart was released, as well as any newly compiled routine changes (see the “Chart Updates” sidebar on the right).
The U. S. Government no longer prints paper copies of its raster nautical charts. However, NOAA provides digital images of its raster charts to NOAA certified chart agents, from whom the public may purchase NOAA paper nautical charts.
Certified chart agents ensure that the charts are printed at the proper scale and quality to meet U.S. Coast Guard (USCG) chart carriage requirements. In fact, only charts printed by a NOAA certified chart agent are accepted by the USCG as meeting chart carriage requirements for commercial vessels. No other raster chart format meets USCG carriage requirements.
Raster Image Definition
Some NOAA certified chart agents offer additional premium services, such as printing charts on waterproof materials, and printing user overlays on charts.
NOAA paper charts fulfill IMO requirements for ECDIS backup.
To purchase a paper nautical chart, contact a NOAA certified chart agent
These are full size Adobe Portable Document Format (PDF) images of NOAA paper nautical charts. PDFs may be viewed with free PDF readers such as Adobe Reader. Others may be found with an Internet search for “free PDF reader.”
PDFs may be downloaded free from the NOAA chart locator.
Most, but not all, charts may be printed at true chart scale on plotters that accommodate 36” wide paper.
Paper plots of Full-size nautical chart PDFs DO NOT meet USCG chart carriage requirements for commercial vessels. Only NOAA paper nautical charts printed by a NOAA certified chart agent, who will ensure that the charts are printed at the proper scale and quality, meet USCG chart carriage requirements.
Full-size nautical chart PDFs may be downloaded free from the NOAA chart locator.
NOAA Booklet Chart Example
Booklet charts are reduced scale copies of NOAA paper nautical charts divided into a set of a dozen 8.5” x 11” pages that show different portions of a chart.
The image at left shows the index of the 12 chart pages of booklet chart 13246 of Cape Cod Bay. The extent of each page extends past the boundaries shown in the index, so that the coverage of each page overlaps a bit with adjacent pages.
These pages can be printed at home (double-sided or affixed back-to-back) and assembled into a booklet.
Other pages in the booklet include excerpts from the U.S. Coast Pilot® and other information such as descriptions of navigational aids and hazards in the area. Emergency information for the charted area is printed on the back cover.
Booklet charts DO NOT meet USCG chart carriage requirements for commercial vessels.
Booklet chart PDFs may be downloaded free from the NOAA chart locator.
NOAA RNC® charts are full-color, geo-referenced, digital images of NOAA paper nautical charts.
RNCs can be used with global positioning system (GPS) enabled electronic chart systems or other “chart plotter” display systems to provide real-time vessel positioning.
NOAA RNCs comply with the International Hydrographic Organization RNC Product Specification.
RNCs are approved for use by IMO ECDIS mandated vessels only if adequate ENC data is not available. Since complete ENC coverage is available in all U.S. waters, vessels required to use ECDIS may not navigate with NOAA RNCs.
NOAA RNCs DO NOT meet USCG chart carriage requirements for commercial vessels.
NOAA RNCs may be downloaded free from the NOAA chart locator.
The NOAA RNC Tile Service is comprised of 15 million individual chart tile images.
Each full RNC is cut into thousands of smaller “tiles” that display much faster than full RNC images.
The tile service provides geo-referenced, nautical chart tile sets for the public that comply with several web map and map tile standards.
NOAA RNC tiles can be used with GPS enabled electronic chart systems or other “chart plotter” display systems to provide real-time vessel positioning. Tiles are also being used on third party nautical data integration websites.
NOAA RNC tile service data DOES NOT meet USCG chart carriage requirements for commercial vessels.
More information about accessing RNC tiles is available at the RNC tile service webpage.
Two Ways to Download Raster Products
Raster
The Chart Locator is an online, interactive map that enables users to locate, view, and download individual RNCs, Full-size nautical charts, and BookletCharts, as well as ENCs.
The RNC listing provides several options for downloading individual RNCs or groups of RNCs bundled by state, U.S. Coast Guard District, and other groupings, including downloading all RNCs at once.
Related Links
Three ways to download Raster Products
The Chart Locator is an online, interactive map that enables users to locate, view, and download individual RNCs, Full-size nautical charts, and BookletCharts, as well as ENCs.
Rasterize
The NOAA Nautical Chart Catalogs are seven sets of 8.5”x11” formatted, regionally based, catalogs that are easy to print at home. The chart catalog webpage enables you to download the catalogs, as well as to view and download individual raster chart products.
The RNC Listing provides several options for downloading individual RNCs or groups of RNCs bundled by state, U.S. Coast Guard District, and other groupings, including downloading all RNCs at once.
Raster Vs Vector
Related Links