Latest Contributions by RichardFairhurst

Or is there anyway that I can view the source code of dissolve or merge process tool? There is no need to use any scripting.  You can do this with the basic geoprocessing tools and a simple ModelBuilder model that chains the tools together. 1.  Use the buffer tool to make your parcels have a 100 feet buffer around them.  2.  Dissolve the buffered output on owner name with the option that makes single part polygons. 3.  Use the Spatial Join Tool on the original parcels and the Buffered and Dissolved output using the One to Many option (make sure the original parcels are the primary input and the Dissolved polygons are the sencondary input). 4.  Select all the results of the Spatial Join where the Owner name of the original polygon is the same as the owner name of the dissolved polygon. 5.  Dissolve the Spatial Join output selection using the Owner Name together with the FID of the dissolved polygon and use the multi-part option. The final dissolve will have all parcels with the same owner name that are within 100 feet of each other dissolved using the original parcel boundaries.  Multiple polygons for the same owner name will exist in the output if there were multiple areas that did not dissolve together when the buffer was applied. ... View more

In VB Script you would do the following: Parser: VB Script Use Codeblock: checked Codeblock: If [Other_Field] = 1 Then   Output = "Minor" ElseIf [Other_Field] = 2 Then   Output = "Major" Else   Output = [Layer] '  Use the existing value of the field being calculated so that it won't change. End If expression: Output ... View more

Hello all I have a problem that I believe can be solved with model builder, however I have limited experience using model builder and need some help putting it together. Problem: My business is in highways maintenance. Everything we do is located by using 'Sections' and 'Chainage'. A section is simply a defined length of road which has a unique reference and the chainage is the distance in mtrs along the section. I have a polyline shp for my roads. Sections have a defined direction and the lines are digitised accordingly so that the start and end are always the right way around. When any new road surface is laid, we need to know the start and end points of the new road surface in 'section & chainage' format. It is difficult to record measurements in this way on site as sometimes the beginning of a 'section' will not be accessible and so a measuring wheel can not be used, but we will log GPS locations on site. Solution: My idea is to build a model that allows a user to input a GPS location (preferably in 12 figure OSGB e.g. NZ 12345 12345) and for the model to output the 'section' and 'chainage' of that point (or closest possible). Method: I think the 'core' tool in the model is going to be 'locate features along routes'. I have used this tool before with existing data in tables. What I'm stuck with is providing an input because there is no 'feature' as such. So perhaps I need the first step in the model to create the feature (a point shp)? Is there a tool that creates a point shp by entering coordinates? I thought about 'Make XY Event layer' but does that need a table as an input? This is where I am up to. I think I know what I want; I just don't have the experience to throw a model together knowing which tools to use. Any help appreciated!!!!!!! Thanks Chris You do need a table as input to Make XY Event Layer, and that is the tool to use.  You are going to have to take the data entered by the user and create a table or feature class at some point, but you can create an in memory table and/or feature class to generate the point event table and locate features along route table if you do not intend to store these values. 1. Basic starting point is to copy a table in memory by borrowing a schema already built to store the Lat Long of the user.  http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Using_in_memory_workspace/002w0000005s000000/  To make it simple the copied table should have a single record in it with blank data. 2. Use Field Calculator to fill in the Lat Long fields from user input into the in memory table. 3. Generate the XY point event table (set your environment to the same coordinate system as your routes). 4. Process locate feature along route to an appropriate output (in memory, temporary or permanent table). 5. Do whatever other process you need to do to translate the Route ID and measure to your section and chainage (if the routes are not already built to output this information). 6. Append the final output to a QC database. ... View more

An invalid SQL statement was used - I've never seen this before. Has anyone else? What is the cause and how can I fix it. It seems to be map specific. I know I can make a new map and it isn't happening in all my maps. I'm very curious as to why it's happening and if there is a way to fix it. It normally occurs if you have a label expression that was stored on a layer that no longer makes sense.  If field names were dropped or changed this error will occur when the label engine fires up if the label property of the field is still enabled.  It should list the Feature Class that is failing in the error message, which should lead you to the layer that is failing.  If this is not it, then the definition query of a layer is similarly corrupted. ... View more

Hey Guys, I am trying to join three different layers. I have one layer of my state (Florida), one layer that i created from the Florida layer where i used the dissolve tool to break the state up into several regions, and then i have an excel file that i am working with that has population data. What i need to know is how many regions have a population greater than xyz and a population density of xyz...Now, to do this i joined my spreadsheet of population data to the Florida layer. Then, i took my dissolved layer and put it on top of the Florida/Spreadsheet joined layer. My idea was that if i spatial joined the dissolved layer with the underlying layer it would aggregate the data and tell me the population (since its by county) of all the counties that make up say Region 1 so i can then tell how many people there are in Region 1....well when i added up the population from my spreadsheet of the counties in Region 1 i get like 490,000 people but when i spatial join it says that the population for Region 1 is like 800 something thousand. I have used the quick right-click join you can do in the TOC and i also used the Spatial Join tool in the toolbox and they both yield the same results. Can anybody help because i can't figure it out to save my life right now... You cannot use Spatial Join for Polygon to Polygon matches like this, because every boundary touch will cause a join, even if the interior of the two shapes has no overlap.  Export the centroids of the county's first and then to the method you are attempting.  The points should fall within only one region polygon and when they are summed they should add up to the correct amount. ... View more

I forgot to mention that in the final join, before the export, that you should also hide the joined table's ObjectID field.  The objective is to make sure that no field names of the two tables are duplicated so that when you export you get normal field names in the output.  If any field names duplicate, then the original table name gets appended to the field name, which you don't want. ... View more

Just started in with Linear Referencing, and have set up a Route, and was wondering if there is a way to extract information (measure) from the route to another feature, i.e. a culvert intersecting the route to obtain the SLM location of that feature. Use the Intersect tool with the points option and the Routes as the primary geometry.  The M value of the intersection will be in the point together with the Route ID and the culvert information.  Calculate the M value to a field using a Python Field Calculator calculation of: !Shape.Centroid.M! ... View more

"Then I would locate the point on the line to get M values for the points " I'm a bit confused by this part. What do you mean and how exactly do I locate the point on the line to get M values for the points? Use the Locate Features Along Route tool to get the M values of the points once you have an LR route system or roads established.  http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//003m00000007000000.htm  Probably this step is optional, since I believe the split at points tool will interpolate the M values of the line ends automatically. ... View more

Hi folks, I am looking for a tool that I can use to select the highest value within a set of similar values.    The values are alphanumeric, and are essentially two parts merged into one field - a master ID to the left of a decimal and a segment ID to the right of the decimal.   Each "master" has a different number of segments.  I would like to select the feature with the higest segment ID for each unique master ID.  There are roughly 5000 unique values in this field.     For instance, in a series of AB1.1, AB1.2, AB1.3, YZ4.1, YZ4.2, both AB1.3and YZ4.2 would be selected.     I would prefer to do this operation with the out-of-the- box functionality & GP tools, but could work with Python if necessary (I am an absolute novice).  Any suggestions on how to approach this?? Thanks!! Sean The only way to do this without use of Python would be to split the master and segment ID portions into two separate fields.  Then you could use the Summary Statistics tool on the master field with Max for the Segment number field.  Parsing it would be easy enough using the period as the split character (examples will follow if you want to go this route).  However, if maintaining parallel field values does not work for your workflow, then you need to use Python to handle the single field values. ... View more

The problem is, if I do a spatial join of points to polygons, ArcGIS grabs the info from either polygon, so I can't be sure that a given point is related to the proper polygon. If I do a spatial join of polygons to points, ArcGIS grabs the info from whatever point is "closest" to the polygon, whether or not the point belongs to the polygon. So no matter which way I perform the join, I can't trust ArcGIS to have joined polygons to the points that generated them. How can I get the proper polygons' identifier into the attribute table for the points, but only if the point belongs to the polygon? Much head scratching here. Thanks for any ideas. What is wrong with the Join One-To-Many option for Spatial Join?  As long as there is a species attribute in both the polygons and points you spatial join you can  easily select the set of resulting records that had a match.  Just extract those points or polygons from the result when you are done and disregard the rest.  Then do what ever additional analysis you want to do with the extracted feature set.  Since the buffers contain the original point's id value you can also eliminate self intersecting polygon/point combinations in those results from the extracted set. You probably can do it in a single Spatial Join using the point data with a copy of itself using a 100 foot tolerance. Or possibly dissolve the original buffer polygons using the species attribute as the unique value and uncheck the multi-part feature option to create separate contiguous polygons that are all for the same species and then run the spatial join to the points and do the above. ... View more

Many thanks for your reply. I had read about linking "Summary Statistics" with a tabular join. When you say "join back to the original to do selections" do you mean a tabular join? The problem is that after the summary statistics, all I have is the Maximum value and an ID value - is there a simple means by which I can also return the value of that polygon which has the maximum value? Thanks again for your help, Paul Actually, normally for this type of analysis I do not use the ID value, because every record will be exported in the summary or an arbitrary min or max ID value will be outputted.  I usually create a dummy field and make every record have the same value in that field (for example all records have 1 in that field).  That is that case field that I summarize and tabular join to.  The summary produces the Max value for the table or current selection.  I use the join and a select by Attribute (Select from current selection if the summary was on a selection set) and find the record with a value equal to the max summary value (actually I really us a range relative to the Max value that is very small if the field is a double, i.e., Table.NumberField >= SummaryTable.MAX_NumberField - .0001 AND Table.NumberField <= SummaryTable.MAX_NumberField + .0001, because there can be slight rounding of the value during the summary that prevents the use of = ). ... View more

For performance reasons only coordinate values are actually readable from the arcpy.geometry operators.  Geoprocessing deals with the parametric elements, but not the arcpy geometry operators.  At the users conference the programmers said it had to do with optimizing online performance, which was a key design requirement for arcpy.  They recognized that you will screw up geometry if you use arcpy operations on parametric data, but offered no solution. ... View more