Latest Contributions by Bud

Regarding SDE.ST_GEOMETRY shape object columns (Oracle): Rumor has it, true curve info (aka CAD blob data) is stored separately from ST_GEOMETRY info — all within the same shape object/column. In other words, if we query the geometry via ST_GEOMETRY functions, we don't have access to true curve data, since it's stored in a separate object attribute (an LOB attribute). (I imagine the wording above is wrong, but that's because I don't have any documentation to reference.) Could information about the above be added to the docs? Otherwise, I'm just fumbling around in the dark. I know the usual suspects are likely to say, "You can't access the CAD blob via ST_GEOMETRY anyway, so it's a moot point." That might be, but I still need to understand how it's been set up...so I can understand what the limitations are and how to work around them. For example, I need to understand how ST_GEOMETRY pre-densifies the true curves into straight segments. What logic is used for the pre-densification?   Edit - Related: Why did a polygon lose 76 sqft (Shape.Area) when exporting from Oracle ST_Geometery to File GDB? ... View more

The ArcGIS Oracle privileges doc —> DATA CREATOR section should include CREATE INDEX privilege info: Privileges for using ArcGIS with an Oracle database  CREATE INDEX is an important privilege for data creators. Especially since we can use it to create function-based indexes (spatial and non-spatial). Omitting that privilege from the doc seems like an oversight. ... View more

There seem to be three different wordings for converting XY data to points: 1. Right click layer in TOC --> "Display XY Data" I find that wording to be misleading. The word "display" makes it sound like we're creating a dynamic event layer, which isn't the case. It creates a new feature class. I know the info in the mouseover explains it a bit further. But I honestly don't usually think to hover/wait/read the mouseover text. Could the "Display XY Data" wording be improved? 2. Ribbon --> Map tab --> "XY Point Data": The wording in the subscript is misleading. We're not simply "Adding x,y point data to the map". We're creating a feature class.  3. Ribbon --> Analysis --> Tools --> Search for "XY" --> "XY Table to Point" GP tool. This tool is pretty straightforward. It creates a new feature class, which is clearly stated in the tool description. And is obvious because we need to fill in the "Output Feature Class" parameter. Note: The three options above are not to be confused with the "Make XY Event Layer" GP tool, which creates a dynamic event layer, not a feature class. Idea: If I understand correctly, all three options use the same underlying GP tool: "XY Table to Point". If all three options do the same thing, then why not use consistent wording, to avoid confusion from the user? And why not make it crystal clear that all three options create a new FC? Feel free to let me know if I've misunderstood something. Cheers. ... View more

In ArcGIS Pro, it seems like XY Event Layer functionality has been removed from context menus. It was easier to create XY Event Layers in ArcMap. Just right-click the layer in the TOC: Whereas in Pro, right clicking gets us a "Display XY Data" tool, but that's misleading because that tool produces a static output in a FC. That's not what I want; I want to create a dynamic event layer. The "Add Data" context menu in Pro doesn't have an XY event layer option either:   The same thing applies to linear referencing Route Event Layers. That functionality has been removed from menus too. Is there a reason why event layers were made less convenient? (removed from the menus) ... View more

I came across a mechanism that can help with slow Oracle queries in some scenarios. I thought I'd share. If we have a slow Oracle query, we can add the /*+ result_cache */ hint to the SQL. That hint tells Oracle to cache the result of the query until the next time the data is edited. Query Result Cache in Oracle Database I think that's a pretty powerful concept. Why re-compute a query every time we use it? Why not save the results until the underlying data changes? --get st_geometry line startpoint select /*+ result_cache */ objectid, sde.st_x(sde.st_startpoint(shape)) as startpoint_x, sde.st_y(sde.st_startpoint(shape)) as startpoint_y from sidewalks --initial load takes 20 seconds due to slow st_geometry functions (14,000 features) I was quite happy when I figured that out! With that said, there are significant limitations: A big problem is: The query can't output a geometry column (object column)...or rather, it can, but the result cache hint won't be invoked. In other words, the query can't be a traditional spatial query. That's a real bummer. (link1, link2, link3) With that said, we can still use geometry columns in the query, like I did in the above startpoint query. We just can't output a geometry column in the final result. But there is a workaround to #1 above...when the geometry type is points: Make an XY Event Layer in ArcGIS that converts the X & Y number columns to points in the map. I've found XY Event Layers to be surprisingly fast...so that solution seems to work well. But of course, that doesn't help us when we want the output to be lines, polygons, or multi-part points, since we can't create an Event Layer for those geometry types: Idea: Event layers for lines, polygons, and multi-part points (via WKT). I'm not aware of a workaround. And to be clear, the Query Result Cache works perfectly fine for non-spatial queries, which I have lots of. If the underlying data is edited often, then this might not be the right solution. For example, for my startpoint query above, it takes 20 seconds to re-cache the result, which feels like an eternity. If editing doesn't happen often, then it's not a problem...I can deal with the slow re-querying once and a while. But if editing happens regularly, then the entire query needs to be re-computed, even if only a single row was affected by edits. Whereas other solutions, such as populating a helper FC via attribute rules, database triggers, a materialized view, etc...only need to sync the edited rows, not the entire dataset. So those options might be better in some cases. Options for computing fields. For what it's worth, ArcGIS Pro seems to be a lot better at handling a cached XY Event Layer than ArcMap. ArcMap re-queries too often when making un-versioned edits...it re-queries after any mouse-click that modified a feature, even if unsaved, which is extremely aggravating. And when re-querying is happening in ArcMap, the mouse is captive to the loading icon...we can't do anything while we're waiting. Whereas ArcGIS Pro loads the layer in the background, allowing us to continue working while it loads. And in Pro, un-versioned edits won't trigger a re-query until the edits are saved, which is good. Note: Both ArcGIS Pro and ArcMap handle versioned edits properly — the XY Event Layer doesn't re-query until the edits are saved. There could be other limitations too. And I'm sure there are other database-related things to consider when storing results in the Oracle cache. Consult your DBA if in doubt, etc... Summary: As with any performance improvement mechanism, there are lots of tradeoffs...it's useful in some cases, but not others. As mentioned, there are lots of alternative techniques we can use that have their own pros/cons. Maybe the benefit to this one is that it's dead-easy to implement (just add a line to your query), doesn't require begging the DBA team for stuff,  and doesn't require custom code/additional FCs to manage. I really like the idea of caching, rather than constantly re-computing for no reason. I submitted a similar idea, but for caching in the application in ArcGIS: Event layers/query layers: Control caching settings for better performance.  Cheers. ... View more