Frequently Asked Questions
1. I left the office still connected to the Hub geodatabase, and when I returned in the morning, my connection had been cancelled. Why is this?
Periodic data updates are done to the Hub geodatabase. This is normally done at 2AM. It is necessary to remove all users's locks prior to updating the geodatabase with the new information. If you are planning on running something that requires a connection all night long, you can contact us. We may be able to postpone our update.
2. How do I set up an ArcGIS layer (.lyr) file? I want to pre-define the data source and display characteristics to make things easier on myself and the people in my organization.
In ArcGIS, you can do this with ArcCatalog or with ArcMap. If using ArcCatalog, right-click on the selected data set, and from the menu, select "Create Layer…" You will be presented with a dialog, where you will browse to where you will name the file and where you want to store the .lyr file (we suggest one standard area, so that all users will benefit). Use ArcCatalog to browse to the location of the .lyr file, right-click on the name, and select "Properties…" from the menu. You can now customize the display properties by clicking on the General tab to set the display scale, clicking on the Symbology tab to set the display characteristics, etc.
You may find it easier to set up the layer file using ArcMap. Load the information into ArcMap, set the display characteristics of that data. When ready, right-click on the data set name, and select "Save As Layer File…" from the menu. You will be presented with a dialog, where you will browse to where you will name the file and where you want to store the .lyr file (we suggest one standard area, so that all users will benefit).
3. In ArcMap, I am trying to extract data to a shapefile from a feature service by right-clicking on the layer, selecting Data, then Export Data... After a bit, my computer appears to become locked up or runs very slowly and the Export Progress window doesn't show anything happening. I've let this go on for 30 minutes, and still nothing has happened.
Extracting data from a feature service in ArcMap appears to cause ArcMap to do a severe amount of pre-processing prior to the extraction. This work is not displayed in the Export Progress window and can take a long period of time. Please shut down as many applications as possible, to free up all available memory and minimize load on the CPU. During this pre-processing, ArcMap will likely consume 100% of the computer processor and begin to consume large amounts of computer memory. Unless the computer runs out of memory and swap space, the extraction will eventually complete.
4. When viewing the Water_Poly feature class in ArcMap, I see large areas of what appear to be water in the northern and northeastern part of the state. These large water areas do not exist. Why are these displayed?
If you look at the attributes for these areas, you'll see that these polygons have no attributes. The reason these polygons show up, is that in the processing of this GIS data, there are areas where mainly streams and irrigation ditches close into polygons. You could also have this occur where you have a swamp feature joining two lakes that drain to two different basins which ultimately drain into the same river downstream. Or you might have an intermittent stream that causes an area to close into a polygon, but you might not think about it being there since it may be dry most of the time. In any case, there are several different scenarios where the lines in the map layer could form closed polygons, and thus, show up as water areas when you just pull up the data and look at it with out filtering out the polygons that aren t actually water features.
Here's how to get rid of those water areas. Assuming that you are already going into the layer properties to change the random color that ArcMap assigns to data brought, this is where you'll break out the water features. On the Symbology tab, you'll see on the left side Features, Categories, Quantities, Charts, and Multiple Attributes.
- go to Categories
- select Unique Values
- set your Value Field to Major1
- and click the Add All Values button
- uncheck the <all other values> box
- click on the 0 value in the legend and remove it with the Remove button.
You should only have USGS codes that stand for water features, and thus will get rid of upland areas that initially show as water features.
Yet another method would be to use the items:
Flow_type which breaks the dataset into perennial versus intermittent. If there is no value present, it's not a water feature.
Feature_type again, if there is no feature name, it's not a water feature
Or, if you use Unique Values, many fields to categorize your data, you can easily remove those polygon features that are showing up by default, and show many different unique combinations of feature types. Once you ve defined what you want to display, you'll probably want to create a layers file so you don't have to set the symbology every time you add that data layer.
5. When I try to run the Hub Explorer with Internet Explorer 6.0, I get an error message, "A runtime error has occurred. Do you wish to debug? Line 169. Error: invalid argument"
This can be a problem if you have recently installed Office 2003. In Internet Explorer, click on Tools, then click Internet Options. In Internet Options, click on the Advanced tab. Under the Browsing section, click to SELECT "Disable script debugging." Click to CLEAR "Display a notification about every script error." More information can be found on the Microsoft web site: http://support.microsoft.com/default.aspx?scid=kb;en-us;822521&Product=ie600
6. I used to see the map coordinates in the browser status bar at the bottom of the browser but they no longer appear. What has happened?
7. I am confused on the definition of township. Sometimes I see or hear township labeled with a name such as "Grand Harbor" and other times with a number such as "159." What is going on?
There are three different ways in which the term "township" is used in geographic and cartographic discussions.
One of the most common references to the term "township" is used in describing the U.S. Public Land Survey System (PLSS). This is the common legal description used in land holdings and refers to a system that was developed in the early 1800’s for describing surveyed land. These townships are also called survey townships or congressional townships (because they were defined by U.S. congressional mandate). This is the system of having a township, 6 miles by 6 miles in size, subdivided into 1 mile by 1 mile sections.
Image 1 (36kb gif) [taken from Maps for America, Third Edition, Morris Thompson, USGS, pg. 81, Fig. 87]
These townships also have a numbering system that uses the term "township" to indicate the northing row of townships established from an established baseline. Ours (North Dakota’s), is in Arkansas. Using Township 159 North as an example, this indicates that it is the 159th township row that was established north from the baseline in Arkansas. If one takes 159 and multiply by 6 (miles), the result will be 954 miles; and that is about how far north 159 is from the baseline in Arkansas. Range is the term applied to the east/west component of the PLSS township’s "name." As one can see from the example above, Township 2 South, Range 3 West is two townships south of the baseline and 3 townships west of the principal meridian. As an example, Township 159 North, Range 99 West, means it is in the 159th township row north of the baseline in Arkansas and 99 township columns west of the 5th Principal Meridian as shown in the map below.
Image 2 (48kb jpg) [taken from Maps for America, Third Edition, Morris Thompson, USGS, pgs. 82-83, Fig. 88]
The last use for the term "township" is with civil townships. Civil townships are minor civil divisions with established governments. They can have town boards, town assessors, town clerks, their own maintained roads, etc. They are essentially a governmental sub-division of a county. Many times these townships correspond with PLSS townships. Many times they don’t. There are civil townships in Golden Valley County, North Dakota that cover 4 PLSS townships (i.e., 144 sections). There is one civil township in Ransom County that covers one complete PLSS township, and half (18 sections) of the PLSS township to the south. Most, if not all, of these townships have established names such as the Town of Almond, or the Town of Rose, or the Town of Rome. There are also many areas that are unorganized, meaning that no civil township government structure is in place. There may have been one there at one time, but maybe the residents chose to disband their local government, or maybe the population could no longer support it. Or maybe one was never formed. In either of these cases, the county usually takes over the local governmental issues.
8. How can a township have two sections within its boundaries with the same section number?
As an example, the PLSS surveys of the Sisseton tribal/reservation lands were conducted about the 1869/1870 timeframe, while the surrounding surveys weren't finished until the mid-1880's. A rational explanation is that some mistakes were made due to the surveys being placed in the middle of "no where", 300 miles from the prime meridian and almost 800 miles from the baseline. Normally the PLSS surveys were started in the southeast corner of the township and they would survey each mile north and west until a township was finished. Errors across the township would be corrected when the township was finished by creating government lots on the north and west sides of the township. The townships would be built south to north like a brick building with corrections taking place about every four townships to account for the length of a degree of longitude shortening as you move north (One degree of Longitude at the Equator is about 70 miles while here in ND it is only about 45 miles). So when you consider the time periods and conditions they were working in, and the relatively imprecise methods they were using (compared to now), it's amazing that they came as close as they did. It'd be something like building a skyscraper and putting a window in on the 50th floor and hoping that the wall you built from the ground to the window later would fit exactly. The older surveys hold legal precedence over newer surveys, so nothing would change on the tribal lands even after they discovered the differences.
9. Some of the 250K DRGs have file names that don't match the directories that they are located in. Why is this?
Those files are named that way so that they could remain consistent in the directory structures for the 24k, 100k, and 250k map series. Even though data are duplicated in the odd directories, it is because a 250k map covers a 1 degree x 2 degree area. All of the other directory structures are based on 1 degree x 1 degree blocks. This makes it easier for people to find their map sheet without necessarily knowing that a 250k sheet is 1x2. For example, if you are looking for the sheet that corresponds with 45099, you simply go to that directory. You don't worry about whether you should check 45100 or possibly 45098, you know that the map sheet in that directory covers the 45099 block. You might want to take a look at the 250k_DRGIndex.pdf file that is in the main directory
10. Some imagery does not print with the Hub Explorer, is this a bug?
All imagery should print and technically the software that we use for the Hub Explorer should allow printing. A fair amount of time has been spent looking for a solution to the problem with no success. Typically it is the most recent imagery that does not print. This is because that imagery is served up using a different piece of Esri technology. The existing Hub Explorer will be replaced with a newer version that will support printing. Meanwhile, please have patience and consider using ArcGIS Explorer to utilize the web services from the GIS Hub.
11. Why is there a number for the HU_12_NAME in the Watershed Boundary Dataset?
Although not very many nationwide, some hydrologic units (HU) carry their number as their name. That is the case for over 300 of the 2,656 hydrologic units in North Dakota. The number is used in places where there is no significant hydrological features or where the hydrologic features are used for larger, parent features, such as near Lake Sakakawea or the Missouri River. We have elected to give many units its number for its name since there is no other water feature that can be used. As the WBD is a certified dataset, this choice was reviewed not only at the state level but the national level as well.
We strive to use GNIS (Geographic Names Information System) names whenever possible, if there is a GNIS feature that falls within the boundaries of a hydrologic unit. In some cases, we could have used a named cemetery or school as a name, but the preferred standard is to use a named hydrographic or geomorphic feature on the landscape (coulee, river, stream, bluff, hill, etc.). If there is no other hydrologic name that would be appropriate for a particular HUC_12 unit, the number is used. It is a common occurrence in North Dakota where there are large areas of un-integrated drainage, unpopulated places, unnamed intermittent creeks, or a large area of a reservoir that spans at least 27 12-digit hydrologic units.
12. Where Can I Find Source Water Protection Program Data?
What are the ND_WHPA_Community and ND_WHPA_NonCommunity feature classes?
One of the federally mandated outcomes of the Source Water Protection Program is the delineation of Wellhead Protection Areas (WHPAs) and Source Water Protection Areas (SWPAs); these are areas around a well or surface water intake from which a public water system draws its water. The ND_WHPA_Community and ND_WHPA_NonCommunity layers depict those WHPAs and SWPAs that have been completed by the North Dakota Department of Health-Division of Water Quality. The data is dynamic and the GIS layer on the ND GIS hub will be updated at least twice per year in the spring and the fall.
What is the North Dakota Source Water Protection Program?
The North Dakota Source Water Protection Program was developed in response to the 1996 Safe Drinking Water Act amendments that required all states to define and assess the source waters of public water systems. All public water systems that have wells or surface water intakes are participants in the Source Water Protection Program. Three elements of the Source Water Protection Program are federally-mandated requirements and are completed by the Department of Health:
- Delineation of the wellhead protection area (WHPA) for groundwater systems or source water protection area (SWPA) for surface water systems,
- Completion of a contaminant source inventory, and
- Completion of a susceptibility analysis.
The remaining four elements (development of management strategies, development of contingency plans, public awareness and procedures when installing new wells) are strictly voluntarily and can be pursued by the governing body of the public water system.
How do I get more information regarding the North Dakota Source Water Protection Program?
For more information on the North Dakota Source Water Protection Program, a list of direct contacts for North Dakota Public Water Systems, or site specific information please see http://www.ndhealth.gov/WQ/GW/sourcewater.htm or contact the North Dakota Department of Health, Division of Water Quality at 701.328.5210.