Category Archives: Geodatabase
LAS Dataset: How to use the 3D Analyst toolbar with my LAS Dataset
Lidar data is become increasingly available and there are likewise new tools to analyze and display the data. LAS is the public file format for the interchange of three dimensional point cloud data between data users. LAS information can be … Continue reading
Easy Connect – Connecting to ArcSDE just got easier!
A lot of changes were made at ArcGIS for Desktop 10.1 regarding database connections within the client software. The ‘Add Spatial Database Connection’ dialog is renamed to ‘Add Database Connection’, and new functionality is added, allowing connections to enterprise geodatabases and other … Continue reading
Connecting – To Be or Not To Be with ArcSDE [10.1]
Are you working to put together a migration plan for the transition to ArcSDE 10.1? There are some new changes for connecting and disconnecting users with ArcSDE 10.1!
Good to Know
One of the more significant changes with ArcSDE 10.1 is that the default means of connecting to the geodatabases is via Direct Connections. And gone is the script, i.e. sde:sqlserver:servername, replaced by simply providing the instance name where the RDBMS resides.
Table or Dataset? That is the question… if you are talking about a Mosaic Dataset
The Add Raster to Mosaic Dataset tool has many input options to consider when adding your data, including choice of raster type. Within the help documentation, there are twenty one different raster types to choose from among sensor products, aerial imagery, … Continue reading
Ye Ole Db Connection
"The fabled blue marker, what do you do?!"
Our lives are filled with things we often overlook. Case in point, what are the little blue reflectors on the road that you see on the way home from work every day? I’ve tried to establish a pattern. Are they marking the center of the lane? Sometimes they’re right on the road center line, sometimes they’re right in the middle of your wheel path, thump thump, and sometimes they’re barely on the road at all. If you look, you’ll see them all the time; you just have no earthly clue as to what they actually do. Continue reading
New ArcGIS Performance calibration tool
Ever wonder how long your Desktop application takes to render mapped features on a layer to layer basis? Or have you ever needed to know the time it takes to edit mapped features from a particular edit version?
What is the NET_BUILDERR Table, and What Can It Do for Me?
So you have built a Geometric Network and encountered some errors in the process. Enter the NET_BUILDERR table, a resource to help you correct any potential problems uncovered during the build.
The NET_BUILDERR table is a table that is output during the creation of the geometric network. The table is generated if errors are encountered and if the geometric network is owned by the user or the schema that builds the geometric network. This table is created n the same Feature Dataset where your network resides and can be easily previewed in ArcCatalog. Continue reading
Null Doesn’t Mean Zero?
How to add different-sized rasters with NoData Values
One of the most common forum topics is on how to add two rasters with different spatial extents and get a result more than just where the two rasters overlap. Well, the reason the result is only those areas has to do with null values.
There are environment variables to modify to ensure that the rasters line up (snap raster) and the extent is preserved during the process (Spatial Extent). Fixing the environment setting alone will still not fix the output of the process. If you modify the spatial extent to match the “union of inputs”, the output raster will have the correct spatial extent, but the only values will be the values where the two rasters overlapped. So what is going wrong?
Obviously it is the pixel values … or, wait, I guess it isn’t that obvious. Try this piece of wisdom provided by forum poster and Product Engineer, Eric R.
Pixel value + NoData Pixel = NoData Pixel
Pixel value + 0 = Pixel value
Pixel value + Nothing (because your extents are different) = Nothing.
Two different rasters used in calculation (NoData is red).
Sum of Rasters
You may be asking, “What is actually happening? Are the values being used in the analysis or not?” Well, the answer is they will be as long as part of that equation doesn’t include a null value. If there is a null value present that will make the output null, then the output will not be correct.
The next question is how to fix it. Bear in mind, both solutions require you to make the rasters that are being used as the inputs match in spatial extent, pixel registration and cell size. You can use the Copy Raster tool and set the appropriate environment settings to accomplish this. Once you have corrected the rasters, then there are two options depending on the desired output,
1. Set the NoData values to a value of zero, so that when they’re added together, the output will have the correct spatial extent and values from both rasters.
Output from Setting the NoData value (blue pixels = 0)
2. Utilize the Con( IsNull ) workflow to include all of the pixels and add them where appropriate.
Con(IsNull(“RasterSMALL”),”RasterBIG, (“RasterSMALL” + “RasterBIG”))
Output from Con Tool
To recap, there are options to handle the NoData cells. Depending on what output you’re trying achieve, there are different techniques. It’s also important to understand the effect that NoData has when used in raster calculation.
There is a related forum post that discusses using Python to sum multiple rasters together: Calculate sum of 2334 raster layers.
Jeff S. - Geodata Raster Support Analyst
The Evolution of the ArcSDE Geodatabase Upgrade Process at 10.0
When using ArcSDE geodatabases, you may have noticed a change within the 10.0 release in how the upgrade process is now handled. Instead of using the Post Installation Wizard and selecting Repository Setup, as in previous releases, there is a new upgrade process. Upgrading your geodatabase is now performed within ArcCatalog using the new Upgrade Geodatabase (Data Management) tool.
The Upgrade Geodatabase (Data Management) Tool can be accessed in ArcCatalog via the Database Properties of a database connection under the General tab > Upgrade Status or within the Upgrade Geodatabase geoprocessing tool referencing an existing connection. For ArcSDE geodatabases, a direct connection to the geodatabase is necessary to run the upgrade.
Post Installation Wizard at 10.0:
The Post Installation Wizard in 10.0 can be used for the following:
- Defining Database and SDE DBA User – Creating new ArcSDE enterprise geodatabases
- Repository Setup – Populate system repository tables (for new geodatabases only)
- Authorize ArcSDE – Perform Software Authorization of the geodatabase
- Create ArcSDE Service – If using application server service (when not using direct connections)
More changes are on the horizon to incorporate Post Installation functionality into the client tools for the 10.1 release, so stay tuned!
