Latest Contributions by Kevin_C

Hi all,  I'm trying to create a web mapping application that lets users submit data from a map interface to a database existing server-side. I'm wondering if anyone could guide me through the basic design of this client-server architecture. I'm a relative beginner to full-stack web GIS development, so any help is appreciated! What am I trying to do?  I want to build a webmap that allows the user to do these tasks: 1) draw polygons on the map to choose areas 2) fill out a form on the side panel related to the polygon that was created. User inputs information into form and submits it.  When the form is submitted, the polygon data is automatically submitted with it. This data is then recorded into a table in database existing on a server.  I would also like to retrieve this data from the database and put it back on the map for a separate part of the application.  What ideas do I have so far?  I'm using the ArcGIS API for JavaScript to create the webmap. I think the best way to submit the drawn polygons to the database would be to convert them to GeoJSON and then submit it as a string to a new column in the table. But how do I do this? Is there a way in the JS API to convert the polygons that are drawn using the Sketch widget to GeoJSON? Or is there a way to utilize some tool like GeoServer for this, and not go the GeoJSON route?  And after this step, how do I submit this form and polygon data to the Postgres database? I was thinking of using PHP and PDO Any ideas or tips on how to go about designing this app? Thanks! ... View more

I'm following along with this tutorial for Querying a feature layer using the ArcGIS JavaScript API, but using my own layer.  I am trying to query all features within the layer that have a value of 3 in the field called "mag". I'm supposed to get the length of the features in the query result when I console.log. This should not be 0. But I am getting a result of 0, implying that I didn't get the query correct. What should my query statement query.where = "mag = 3"; be changed to here?  var query = new Query(); query.where = "mag = 3"; query.outfields = ["*"]; query.returnGeometry = true; var queryTask = new QueryTask({ url: "https://services5.arcgis.com/.../arcgis/rest/services/datalayer/FeatureServer" }); queryTask.execute(query) .then(function(result) { console.log(result.features.length) }) .otherwise(function(e) { console.log(e); })   Thanks! ... View more

I have a Map Document that exists on our Department's Network Drive that contains a lot of (<200) feature classes and layers. I wanted to work with one specific feature class and use it for a map I'm creating. So I save the layer as a layer file in my work machine. I then proceed to edit this file using ArcGIS to create new fields, delete existing ones, change symbology etc. I make some pretty heavy changes to the file and realize I screwed up by deleting a column I shouldn't have. Oh well, glad it's backed up in the Map Document.  I check the Map Document and go to the layer in question. The changes I made to the layer file I saved in my local machine were applied to the original layer. The columns were deleted in the original map doc. How is this possible? How does saving the feature class as a separate layer file in my local machine not prevent this kind of screw up?  Thanks for the help. I really hope I haven't made permanent changes to the original layer, although it looks like that may be the case?  ... View more

I have a layer file with several thousand records and a lot of columns. I'm trying to map this by breaking out values from one of the columns into categories. But I don't see an option for Categories in the symbology tab in "Layer Properties". I don't know why this is the case since there are definitely values in multiple columns that could be broken into categories. Here is what the Symbology tab looks like: Is ArcGIS being weird or am I doing something wrong here?  Thanks! ... View more

I have a layer file for a geology layer containing attributes for "Age", "Rock Type" and "L_Code". The layer has symbology defined using the "L_Code" attribute. But I want the same symbology applied using the concatenated "Age" and "Rock Type" fields. Each L_Code matches with exactly 1 Rock Type value and 1 Age value. How can I do this? See figures below.  This is what the original layer file looks like, defined using the L_Code attribute This is what I want the final legend to look like. The label column shows concatenated strings from both the Age and Rock Type fields. Thank you for any help! ... View more

I have a total of 150 maps I used arcpy and the Mapping module to create. Everything works and looks fine, except that some maps have features being hidden by an inset data frame. I cannot change the position of the inset data frame, so that's out of the question. Is there a way using arcpy and the mapping module to pan across the map?  ... View more