by Cynthia Deischer and Ray Postolovski
Juliet: “What’s in a name? That which we call a rose by any other name would smell as sweet.”
Romeo and Juliet meet in Shakespeare’s tale. They are predestined from the start because of their surnames. Juliet tells Romeo that a name is an artificial and meaningless convention. Meaning what matters is what something is, not what it is called. However in the geospatial community, a name is far from meaningless and what something is named is just as important as what something is. Continue reading
by Cindy McKay, Horizon Systems Corporation, Member of the EPA/USGS NHDPlus Team A national compilation of the WBD snapshots used to build NHDPlusV2 has been assembled and is posted at: http://www.horizon-systems.com/NHDPlus/V2NationalData.php The data is posted in both shapefile and File … Continue reading
by Tommy Dewald, USEPA Office of Water The National Hydrography Dataset Plus (NHDPlus) is a suite of geospatial products that build upon and extend the capabilities of the NHD (1:100,000 scale) by integrating it with the National Elevation Dataset (30M) … Continue reading
by Ernest To* – RPS Espey, Carissa Belsky – Crespo Consulting Services, Inc., David Harkins – RPS Espey,
Jim Patek – Parsons Corporation, Steve Stecher – Crespo Consulting Services, Inc., Mel Vargas – Parsons Corporation,
Jennifer Walker – Watearth, Inc.
* =corresponding author
Sedimentation in Texas reservoirs is a significant problem that affects both water availability and quality in Texas. The Texas Water Development Board estimates that Texas’ major reservoirs are losing 90,000 acre-feet per year due to sedimentation. This is equivalent to a loss of 4.5 million acre-feet by 2060 and exceeds the projected increase of 3.4 million acre-feet from new reservoirs. The reduction in storage volume not only impacts water supply but also necessitates the alteration of supply infrastructure to handle deteriorating water quality. Uncertainty regarding rainfall supply due to climate change further burdens the already stressed reservoirs.
by Ariel T. Doumbouya, NHD Team, United States Geological Survey
Fish sampling sites in the Nashua River Subbasin in Massachusetts are linked to the National Hydrography Dataset (NHD) as events using the Hydrography Event Management (HEM) Tools. Events allow scientific information to be linked to the NHD which provides a powerful modeling framework that can be used to locate water related information on the network, establish up and/or downstream relationships, perform habitat and species modeling, and determine relationships between other environmental factors.
by Kathy Isham, National Hydrography Dataset, USGS The US Geological Survey (USGS) has redesigned its applications page for the National Hydrography Dataset (NHD). The new applications page is organized into the six different types of applications that highlight how USGS … Continue reading
by Alison Wood, Graduate Student, The University of Texas at Austin
As GIS users, we often have to collect data from many sources and compile them into a single map. For just a few sources and a single map, this might be feasible. But what if you have to make a new map with updated data every day? Or every hour? Automation can save you the enormous time it would take to do that by hand, and also help to avoid the errors that can happen in repetitive tasks done by hand. In this blog entry, I’ll describe an example of automating a process to retrieve data, execute file format conversions, and update an online map; I’ll also talk a little bit about some of the tools and strategies I used that will be useful for someone else automating a similar process.
The USGS periodically reviews the NHD Data model to determine if changes are needed to better suit our community’s needs. These changes must be approved by a panel in order to ensure the NHD community will not be negatively impacted.
The updates to the NHD model are as follows:
1. Removed attribute ComID from all NHD feature classes and tables
- Removed FeatureComID from NHD event feature classes
- Remove d attribute AboveComID and BelowComID from NHDVerticalRelationships table
- Remove d attribute FromComID and ToComID from NHDFlow table
- Remove d attribute WBAreaComID from NHDFlowline feature class
A new release of the Hydrography Event Management (HEM) Tool is available for ArcGIS 10. The HEM Tool provides full functionality for adding and editing events in the National Hydrography Dataset (NHD). Events are informational data that are linked to the NHD using a linear referencing on NHDFlowlines. The HEM tool handles all the linear referencing mechanics to make working with events simple. Hydrography events support many applications such as resource management, environmental protection, emergency response, fisheries and much more.
Enhancements to Version 2.5 include:
- Added a Pan button to candidate form.
- Candidate form can list an additional attribute per event layer. Values from each event layer’s ‘Display Expression’ field will be listed in the candidate form.
- Import to Events – before starting batch import the tool will now verify the spatial reference of the data frame and the NHDFlowline feature class are exactly the same.
- Import to Events will warn the user if they are about to apply approved imported events to a base table with the same name. Users have the option to stop or continue the process.
- Import to Events can now transfer no fields, just the link field, or all fields. All fields only works for standard field types (string, date, and numeric). Blobs, OIDs, GUIDs and shape type fields will not transfer.
- Create Multiple Events Downstream – Added new functionality (button) to create multiple downstream events from a point layer in the map. Not default on HEM toolbar, found under Customize > Commands > Categories > HEM > Batch Downstream from Points. Option to create overlapping or non-overlapping events from input points.
- Import to Events QC and Batch Sync QC will now allow users to select multiple rows at once and approve them all.
- SourceFeatureID now has an option to enforce unique IDs in event feature classes.
Find out more information and download the tool at: http://nhd.usgs.gov/tools.html.
An online demo of new features will be scheduled for the week of Oct 31st, email firstname.lastname@example.org to attend.
Special thanks to Ariel Doumbouya for providing this post. Questions for Ariel: email@example.com.
With a recent ArcGIS Online update the USA Topo basemap (containing the USGS topo map services) no longer appears in the ArcGIS.com map viewer and Explorer Online basemap galleries. The basemap was replaced by others having more global coverage.
Though it no longer appears in the gallery, the USGS topographic maps continue to be available and can be easily found and used as your basemap whenever you want. Here’s an easy way how to find and use them as your basemap:
Open the ArcGIS.com map viewer with a new map and click Add, then choose Search for Layers: