Data Services Overview

Here is a quick overview of the data provided by SDMI via Web Mapping Serivces (WMS), Web Coverage Services, and Web Feature Services (WFS). Please let us know if you have any suggestions as how to make the services more useful. We also welcome discussion of these services on our online support forum .

Services

  1. Web Mapping Services
  2. Web Coverage Services
  3. Web Feature Services

Web Mapping Services

 We provide a number of Web Mapping Services (WMS) that provide raster (imagery) data and are intended to be used by desktop GIS clients as a base layer.

We provide a wide range of Web Mapping Services:

  1. WMS: Best Data Available
  2. WMS: Extras
  3. WMS: NOAA Raster Nautical Charts
  4. WMS: NOAA Raster Nautical Charts, Unclipped

WMS: Best Data Available

 The Best Data Available layer (BDL) is intended to provide a imagery base layer that covers the entire state of Alaska.

It contains three main layers:

  1. BDL: Low Res
  2. BDL: Mid Res
  3. BDL: High Res

BDL: Low Res
  • The bdl_low_res layer contains the Blue Marble Next Generation July dataset (http://www.nasa.gov/vision/earth/features/blue_marble.html). It is intended to be viewed at scales greater than 250m per pixel


BDL: Mid Res
  • The bdl_mid_res layer contains a Landsat mosaic generated by the USGS from data acquired from 1988 to 1992 and a simulated true colour Landsat mosaic provide by Earthstar Geographics LLC. It is intended to be viewed at scales greater than 15m per pixel. Imagery copyright Earthstar Geographics (http://www.terracolor.net).


BDL: High Res
  • The bdl_high_res layer contains data from a variety of sources and is intended to be viewed at scales from 25m per pixel to 1m per pixel. Images courtesy of Digital Globe, USDA-NRCS, USDA-FS, USGS, BLM, NPS, FAA, Alaska DNR, DMVA, DCED, DOT&PF




WMS: Extras

 The Extras service is intended to provide a number of imagery base layer that do not fit well within the Best Data Available service.

It contains these main layers:

  1. Extras: DRG
  2. Extras: Pseudo Color Landsat
  3. Extras: Shaded Relief NED
  4. Extras: Landsat Pan

Extras: DRG

 This layer group provides four layers, “drg_24k”, “drg_25k”, “drg_63k”, “drg_250k”, which contain the USGS topographic maps for the scales 1:24,000, 1:25,000, 1:63,360, and 1:250,000 respectively. For more information please see the USGS’s topographic maps website.

Extras: 1:24,000 DRGs
  • This layer is called “drg_25k” and provides the USGS Topographic Maps available at the 1:24,000 scale. The area covered by these maps is quite limited and mainly covers the Beechey Point area.



Extras: 1:25,000 DRGs
  • This layer is called “drg_25k” and provides the USGS Topographic Maps available at the 1:25,000 scale.


Extras: 1:63,360 DRGs
  • This layer is called “drg_63k” and provides the USGS Topographic Maps available at the 1:63,360 scale. The area covered by these maps is covers most of Alaska, with the exception of some areas in the Aleutian Islands.




Extras: 1:250,000 DRGs
  • This layer is called “drg_250k” and provides the USGS Topographic Maps available at the 1:250,000 scale. These maps cover the entire state of Alaska.



Extras: Canadian Topographic Maps
  • This layer is called “can_drg_250k” and provides the “Natural Resources Canada”:http://www.nrcan-rncan.gc.ca/com/index-eng.php 1:250,000 scale topographic covering Canada. For more information, please see “Natural Resources Canada Mapping Services”:http://maps.nrcan.gc.ca/topo_e.php . This layer is intended to supplement the other DRG layers by providing topographic data for areas near Alaska that are not covered by the USGS maps.





Extras: Pseudo Color Landsat

This group provides a single layer called “Mid Resolution Pseudo Color (15 meter)”. This layer is derived from the the Landsat datasets provided by OnEarth.




Extras: Shaded Relief NED

 This group has one layer which provides a shaped relief dataset derived from the National Elevation Dataset (NED)

Extras: Landsat Pan

 This layer group provides a single banded dataset derived from Landsat 7’s pan-chromatic band. It was generated from the Landsat 7 datasets provided by OnEarth. It is broken up into two layers to increase the rendering speed.




WMS: NOAA Raster Nautical Charts

 These services provide a copy of NOAA’s Raster Nautical Charts (RNCs) that cover Alaskan waters. These services are to be used for NONE NAVIGATION purposes only.

Included Charts

This service includes all the NOAA RNCs that cover Alaskan waters. The complete list can be viewed here .

Missing Charts

This service does not include a number of charts because of issues with the RNCs metadata. In most cases this was because the charts are in a projection that is not documented, but in a few cases it is because of improper chart metadata.

Here is the list of charts that are not included in the service:

  • 17339 sub-chart #1 HOOD BAY AND KOOTZNAHOO INLET
  • 17339 sub-chart #2 HOOD BAY AND KOOTZNAHOO INLET
  • 16646 sub-chart #1 SELDOVIA HARBOR
  • 16568 sub-chart #2 WIDE BAY TO CAPE KUMLIK
  • 17435 sub-chart #2 PORT CHESTER
  • 16661 sub-chart #2 COOK INLET ANCHOR POINT TO KALGIN ISLAND
  • 17425 sub-chart #1 PORTLAND CANAL NORTH OF HATTIE ISLAND
  • 16240 sub-chart #1 CAPE ROMANZOF TO ST. MICHAEL
  • 16240 sub-chart #2 CAPE ROMANZOF TO ST. MICHAEL
  • 16433 sub-chart #2 SARANA BAY TO HOLTZ BAY
  • 16381 sub-chart #2 ST GEORGE HARBOR
  • 16436 sub-chart #2 SHEMYA ISLAND
  • 16382 sub-chart #2 VILLAGE COVE
  • 16549 sub-chart #2 ALASKA PENINSULA COLD BAY AND APPROACHES
  • The Charts service is meant to provide a unified view of the RNC data, without the collar information. The service is designed to only display charts that are meaningful at the requested scale. The url for this service is “http://wms.alaskamapped.org/cgi-bin/charts.cgi?”. Here is a link to the Get Capabilities document.

Layers

  • This service provides a large number of layers. The visibility of the layers are controlled by scale limits in such a way as so layers are only visible if they are meaningful at the scale of the current request. The recommended way to use the service is to turn all the layers on and let the service choose which layers are visible for a given request.
  • Entrance to Yakutat:


WMS: NOAA Raster Nautical Charts, Unclipped

These services provide a copy of NOAA’s Raster Nautical Charts (RNCs) that cover Alaskan waters. These services are to be used for NONE NAVIGATION purposes only. This service provides the RNCs in the original, unclipped form, and includes the “collar” around the charts. Each chart is in a separate group, and each group contains all the sub charts within the chart. A paper chart might include a number of smaller charts inset inside of it. All of the sub-charts that would compose a single paper map are grouped into a single layer group, with each sub-chart as a separate layer. Please keep in mind that this service includes the collars around the charts. The url for this service is “http://wms.alaskamapped.org/cgi-bin/charts_nc.cgi?”. Here is a link to the Get Capabilities document.

Layers

  • The list of layers included in this service is huge, and so is not included here. The full list can be found here .




Web Coverage Services
  1. WCS: Elevation Data

WCS: Elevation Data

We have a Web Coverage Service up that is intended to serve elevation data. This service is in a testing phase and we would appreciate feedback as to how well it works for our users.

A WCS serves up data values rather than pixels. In the case of the elevation data in is service, it is serving the heights above the horizontal ellipsoid.

  1. WCS: STRM Version 2
  2. WCS: ASTER DEM
  3. WCS: Katalla
  4. WCS: NED 1/3 Arc Second
  5. WCS: NED 2 Arc Second
  6. WCS: Eagle River
  7. WCS: Chugach SPOT DEM
  8. WCS: Kenai Lidar AREA A
  9. WCS: Kenai Lidar AREA B
  10. WCS: Kenai Lidar AREA C
  11. WCS: Kenai Lidar AREA D
  12. WCS: Kenai Lidar AREA E
  13. WCS: Kenai Lidar AREA H

WCS: STRM Version 2


This layer contains the region of the SRTM version 2 dataset that covers Alaska. The layer is called “SRTM_V2”. The horizontal datum is WGS84.



WCS: ASTER DEM


This layer contains a region of the global ASTER DEM covering Alaska. The layer’s name is “ASTER DEM”. The vertical datum is mean sea level.



WCS: Katalla


This layer contains a small bare-earth DEM that covers a small area of the St. Elias Mountains. The layer is named “katalla”. The vertical datum is NAVD88. This dataset is complements of NCALM":http://www.ncalm.ufl.edu





WCS: NED 1/3 Arc Second


This layer contains the 1/3 arc second NED covering Alaska. The layers name is “NED_ONE_THIRD_ARC_SEC” and the vertical datum is NAVD88.



WCS: NED 2 Arc Second


The 2 arc second NED covering Alaska. The layers name is “NED_2_ARC_SEC” and the vertical datum is NAVD88.




WCS: Eagle River


This layer is named “Eagle River” and contains a small 3 foot resolution DEM covering part of the Eagle River area. The vertical datum is NGS 72. This dataset is complements of The Alaska Department of Natural Resources



WCS: Chugach SPOT DEM


This layer is named “Chugach Spot DEM” and contains a 20 meter resolution DEM covering the greater Chugach State Forest area. The vertical datum is “altitude over GEM 96”. This dataset is complements of The U.S. Forest Service



WCS: Kenai Lidar AREA A


The “Kenai Lidar AREA A” layer contains a small 4m resolution DEM covering the Kenai area. The vertical datum is GEOID06 (Alaska) Orthometric Heights. This dataset was provided by the Kenai Watershed Forum.




WCS: Kenai Lidar AREA B


The “Kenai Lidar AREA B” layer contains a small high resolution DEM covering the Kenai area. The vertical datum is GEOID06 (Alaska) Orthometric Heights. This dataset was provided by the Kenai Watershed Forum.



WCS: Kenai Lidar AREA C


The “Kenai Lidar AREA C” layer contains a small high resolution DEM covering the Kenai area. The vertical datum is GEOID06 (Alaska) Orthometric Heights. This dataset was provided by the Kenai Watershed Forum.



WCS: Kenai Lidar AREA D


The “Kenai Lidar AREA D” layer contains a small high resolution DEM covering the Kenai area. The vertical datum is GEOID06 (Alaska) Orthometric Heights. This dataset was provided by the Kenai Watershed Forum.



WCS: Kenai Lidar AREA E


The “Kenai Lidar AREA E” layer contains a small high resolution DEM covering the Kenai area. The vertical datum is GEOID06 (Alaska) Orthometric Heights. This dataset was provided by the Kenai Watershed Forum.



WCS: Kenai Lidar AREA H


The “Kenai Lidar AREA H” layer contains a small 3m resolution DEM covering the Kenai area. The vertical datum is GEOID06 (Alaska) Orthometric Heights. This dataset was provided by the Kenai Watershed Forum.







Web Feature Services
  1. WFS: Inventory

WFS: Inventory

 This service provides a Web Feature Service that allows access to information about the data available though SDMI’s WMS. This includes information about all of the data holdings in SDMI, including license information, resolution, coverage, and a method for obtaining the original data if the license allows. The URL for the service is http://wfs.alaskamapped.org/inventory . More information on how to use the service can be found in our WMS and WFS tutorial .

Please let us know if you encounter problems or have questions.




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