Latest Contributions by ChrisDonohue__GISP

‎10-29-2016

One can normally update the attributes of a feature class without altering the geometry. Typically this is done in an edit session. One can also use Field Calculator outside an edit session to update values. If you are good with Python, attributes can also be updated using a Python Script. So I suspect there are some other factors involved in what you are trying to accomplish. Can you elaborate more on what you are trying to achieve? This will help GeoNet participants in providing solutions. Include what software and version you have available. For example, ArcGIS Desktop 10.3. Chris Donohue, GISP

‎10-29-2016

There are several ways to do this. Here's some methods. Note also the Important Considerations below. 1). If you have access to the Spatial Analyst Extension, you could convert your polyyons to raster using the Feature To Raster Geoprocesing tool (or one of the several vector to conversion tools), specifying the size of the square. Then convert that raster back to vector. Here's the help for ArcGIS Pro, which will give you a general idea of how it works. Look up the specifics in the help for your version and software, as there may be differences: Feature to Raster—Conversion toolbox | ArcGIS for Desktop Raster to Polygon—Conversion toolbox | ArcGIS for Desktop 2). You could create a Fishnet for your project extent. Then use a Spatial Join to attach the attributes to the fishnet. Last, delete the polygons on the exterior that did not cover the input data. The Spatial Join could be performed with either the Geoprocessing tool of the same name or by doing a Join to the Attribute Table of the Fishnet based on Location. Create Fishnet—Help | ArcGIS for Desktop Spatial Join—Help | ArcGIS for Desktop Important Considerations: Before running any process, you will need to decide what the desired result will be when one of the "squares" covers multiple polygons in your input data. In other words, what value would you expect to end up assigned to the "square" in your new fishnet or raster? The above methods will produce different results, so this will need to be considered. Some possibilities (there are several): - Average of all values covered by the new "square" - Only the value at the exact center of the "square" To resolve this: Some methods offer options to change how the desired value is determined, so look at the Help for each method. An intermediate feature class may need to be created to use in the processing. For example, if the desired output is the value at the exact center of the new "square", you may want to create a Centroids point layer of the exact center of each of the new squares and then Join your original data to that point layer, then Join the point layer to the new squares (polygons). http://help.arcgis.com/EN/ArcGISDesktop/10.0/Help/index.html#//00170000003m000000 Chris Donohue, GISP

‎10-28-2016

As a start, I don't have an exact answer for you, but a suggestion to try. I was thinking you could use Replace, but put "" instead of what was used (see thread): Python - using Replace in Field Calculator That said, I'm sure some of the experienced Python folks have a more elegant solution, so I'm curious to see what they come up with. Dan_Patterson Darren Wiens Chris Donohue, GISP

‎10-27-2016

Not sure if this is a possible cause, but some of the results seem odd in ways other than the directionality you mentioned, at least compared to the Quad map displayed. In the North, there are two areas where the derived stream lines seem to go parallel to the contour lines for a distance instead of traveling down the slope as expected. Also, by the label "Upper Rock Tank" the lines go "horizontal" at first (which is a typical output result when derived streamlines cross a water body), but then seem to cross a ridge, which is not what one would expect. Of course, the elevation data you used in deriving the stream lines may be different than the data used when the quads were constructed (time may have passed and the landscape may have changed, the resolution between the two datasets may be very different, etc), which may account for it. Still, it seems odd. Chris Donohue, GISP

‎10-27-2016

Some ideas: Just to confirm - the linework is definitely going uphill, not due to the line direction being reversed when symbolized? Check the linework versus your rasters. To convert from Raster to Vector, did you use Stream to Feature (Spatial Analyst)? ArcGIS Help (10.2, 10.2.1, and 10.2.2) How Stream to Feature works ArcGIS Help (10.2, 10.2.1, and 10.2.2) Stream to Feature Also, if they are all uniformly reversed, as a workaround, one can reverse the line directionality. ArcGIS Help (10.2, 10.2.1, and 10.2.2) Flip Line (Editing) caveats - requires at least a standard license. - alters the input dataset instead of making a new output, so back up your data before running. Chris Donohue, GISP

‎10-27-2016

Thanks for the info Tycho. Our CAD system also does address points first, then falls back on centerlines if the points don't work out. So a question along those lines which has come up for us - would it be worth it to put additional address points at the location where the driveway starts away from the road and give them a unique category like "Access point"? We've run into similar where the CAD can't find a valid address point because the building is far from the road, so it falls back on the centerline data, which is not ideal. Also, some commercial facilities have multiple long private entrances on either side of a property, so even if the CAD finds the right address point, it sometimes gets confused on the best route and picks the longer way when routing. Chris Donohue, GISP

‎10-27-2016

Wait, will NextGen 911 include capabilties for the infamous Shoe Phone? Get Smart - Wikipedia Chris Donohue, GISP

‎10-27-2016

There are several ways to do this: The most basic way is to a Spatial Join. This can be done with either the Spatial Join (Analysis) geoprocesing tool, or by going into the attribute table of one layer and performing a Join using "Join data from one layer to another by spatial location". ArcGIS Help (10.2, 10.2.1, and 10.2.2) Spatial Join Geoprocessing tool ArcGIS Help (10.2, 10.2.1, and 10.2.2) Spatial Join by Location If one has access to an Advance license, one could also consider using the Identity (Analysis) geoprocessing tool. ArcGIS Help (10.2, 10.2.1, and 10.2.2) Identity Geoprocessing tool The one catch will be dealing with the polygons that have two or more grids in them. Probably the easiest way to handle this is to first add a field to the County layer called OriginalArea. Use Calculate geometry to populate this with the area . Then do a spatial join or Identity. In the output, create another field, this one called OutputArea. Calculate geometry on this one to populate it with area. Then create a Percentage field. Populate this by calculating OutputArea/Original Area. Now one has a means to distinguish how much of each county part is in each grid. One can go further with this to refine the processing more to avoid doing manual work in updating the final result (but I will have to scratch my head more, as it is not immediately coming back to me). For example, one can run a Frequency of the counties in the output to find out how many "pieces" resulted from the processing, then join that data back to the output so one can query all the counties that resulted in more than one polygon (and thus need evaluating to determine what the majority grid is). I think one can then Dissolve (Data Management) the output based on Statistics Fields (Optional) of "Max" to rebuild the counties with the grid the covers the most populated, but I have not tested that to be sure. ArcGIS Help (10.2, 10.2.1, and 10.2.2) - Dissolve Chris Donohue, GISP

‎10-27-2016

So a broad question organizational question comes to mind. Who ultimately is the lead agency/organization for implementing NextGen 911 in the United States? Is a State-level agency? Federal? County-level? Or is each PSAP responsible to make it happen? All of the above? None of the above? Total Chaos? Chris Donohue, GISP

‎10-27-2016

Going from Illustrator to GIS can be difficult, as Illustrator uses different formats, doesn't have any capabilities to deal with projections and coordinate systems, and doesn't store attributes. One route to try is to convert the .ai file to .dwg or .dxf. However, there can be some issues. See this older GeoNet thread: Convert illustrator vectors to arcgis There also are some commercial products out there that try to span the gap if one has funds. Here's one of them: Avenza Releases MAPublisher 9.8 for Adobe Illustrator Given your specific project, I would suggest a different approach, though, than using Illustrator. Instead, make the pictures digital (scan), then bring them into ArcGIS with the desired projection/coordinate system already set in the Data Frame. Then Georeference the pictures. Finally, create a new feature class and then use Heads-up digitizing to trace the boundaries into the feature class. You can always export back out to Illustrator if the results need to be there for the final product (exporting from GIS to .ai is less problematic than .ai to GIS). Chris Donohue, GISP

‎10-27-2016

Visuals to add to Joe's explanation: 1). In an Edit Session, with the layer you want to edit Selectable, select the three polygons. Then, on the Editor toolbar, click on Editor, then click on Merge: 2). On the Merge window that pops up, choose the polygon you want to have the others merged into. Click on the 3 different ones in Merge window and it will flash the chosen one so one can figure out which is which. Hit OK once you have the correct one selected. 3). Final Result. To make it permanent, go to the Editor toolbar, click on Editor and then select Save Edits. Chris Donohue, GISP

‎10-27-2016

Interesting. So in NextGen 911 one would have polygons of ESN zones and the system would dynamically access it in GIS to do a spatial join of the information on demand so as to find the correct ESN for the incident location? Chris Donohue, GISP

‎10-26-2016

Tim, Thanks for your input. Quick question. In your comment "The biggest issue will be to get your data ready (left and right ranges, ESN for left and right....)" what is ESN? Chris Donohue, GISP

‎10-26-2016

But.... The big difference between me and the rest of them, and I mean no disrespect, is, like you I'm 9-1-1 focused; they are not. I know what you mean. My group inherited the addressing responsibility for the City two years ago and one thing we immediately found out is that addressing is used by several groups for different purposes. Now I'm not saying this in a bad way, but every group has a specific need of addressing but little interest in the other uses. For example, for the Utility folks we address assets in some cases, but I'm sure the 911 folks really don't care that one of the buildings is served by an landscape irrigation water meter with a slightly different address than the building. So I can see the case where there is the master address database, then the cut-down replicated copies that are sent out to each group that meets their specific needs. Chris Donohue, GISP

‎10-25-2016

There are three required files for a shapefile. In Windows Explorer, look for the following extensions after your shapefile name: .dbf (dbase file, i.e. the attributes) .shx (index file that connects the .dbf to the .shp) .shp (geometry) Then there are several that are nice to have, but are not always available. One example: .prj file (projection file) ESRI Shapefile - components list To ensure that you are sending all the components of a shapefile, I would do as jborgion suggested and Zip them, then send the Zip file to the other user. Chris Donohue, GISP

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My Ideas

Latest Contributions by ChrisDonohue__GISP

Re: How to change value attributes in a polygon fc without changing the geometry

Re: How do I change a map to squares

Re: Using Python to Split Address Field

Re: My flowlines all go uphill, why?

Re: My flowlines all go uphill, why?

Re: Next Generation 911 (NextGen) rollout?

Re: Next Generation 911 (NextGen) rollout?

Re: Assigning each Polygon to a Larger One

Re: Next Generation 911 (NextGen) rollout?

Re: illustrator to shape

Re: How do I join 3 adjacent polygons into 1 polygon? Merge and Dissolve create 1 feature, but it still has the 3 polygons.

Re: Next Generation 911 (NextGen) rollout?

Re: Next Generation 911 (NextGen) rollout?

Re: Next Generation 911 (NextGen) rollout?

Re: Ok, so I know that it is important to copy all files of an ESRI shapefile in Windows Explorer in order to send it to another user. Question: What are the files (at least five) of an ESRI Shapefile that need to be copied ??. Thank you in advance!

Re: ArcGIS 10: Graphics won't display in Data View

Re: Can't set output as intermediate data

Re: Addressing - Plus Code or What3Words (W3W)

Re: How to label "_, Mount" as "Mount _" ?

Re: Raster/Vector Land use Analysis

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