Latest Contributions by AlexanderGray

Distance in decimal degrees is meaningless.  the distance between two degrees of latitude is more or less constant but the distance between two degrees of longitude is roughly 111km at the equator and 0m at the north and south pole.  Assuming your lines are short there should not be a lot of north south variation but since the length of the unit of measurement is different in the X and Y axis, length in degrees are basically meaningless. The length reported by Ipolyline.length will be in the coordinates of the data's coordinate system.  This could be meters, feet, nautical miles and even decimal degrees.  The thing to remember is that is just the distance in the cartesian coordinate system stored in the database (X,Y coordinate system.)  Most coordinate systems depend on a map projection that defines it.  Map projections all have distortion, only equidistant projections preserve distance.  How accurate is the measurement depends on the projection, how much accuracy you need depends on the application.  For high accuracy over long distances, there is a class called MeasurementToolClass part of the defensesolutions to do that.  I have used it back when it was part of military analyst but now it is core functionality. ... View more

Locks are caused by the interaction of ArcObjects COM and .NET framework.  You need to explicitly release any objects referring to the shapefile using the comreleaser.  This includes any cursor, feature, row, featureclass or workspace objects.  The locks will be released when the calling app is disposed because that will release all the objects.  If you explicitly release all the objects by calling comreleaser, you should be able to release the locks without terminating the process. ... View more

I have gotten this intermittently too with an ArcInfo license.  Problem is it is not consistent.  I would like to know if there is a solution. ... View more

Use the comReleaser object when you are done.  You have to use it on the cursors, tables, featureclasses, features,  rows,  cursors etc. or else you will still have objects with a connection open.  It is actually quite tricky.  Even if you just access a object through the property of another object, will will end up with a reference to that object in memory not assigned to a variable...  Make sure you assign these to a variable so you can release it later.  I like to make a using block with a new comreleaser and add all the variables to the be managed by the comreleaser, when the using block end the comreleaser gets destroyed and releases all the references it manages. ... View more

Usually to pass a null by ref in C# you have to declare a variable as object and initialize it to type.missing.  If you passed an empty string in vb.net, I would think you need to pass the empty string by ref in C#, "ref string.empty". ... View more

If you try to add reference to your project, you should have a bunch of ESRI namespaces.  ESRI.ArcGIS.ArcMap should be one of them.  If you have none of the ESRI.ArcGIS ones, the .NET support is not installed (if you have installed ArcGIS before the .NET framework this will happen.)  You can verify this by looking for the "dotNet" folder in you ArcGIS installation folder.  If it is missing, you need to run the installer again and make sure the .net support is installed. ... View more

Thanks Neil, The creategraphics is the part I got wrong.  I was passing the handle of the control to the draw.  That is a level deeper than I usually work at. ... View more

Thanks Neil, The idea of creating my own custom map control is very helpful.  I managed to add a raster layer to a map and set the display to a form.  The only problem I get is the refresh.  I put the activeview.draw call in the on_paint event but it seams after the form loads or if it loses focus or if I resize, it only draws the image if I tinker with the scroll bars that show up on my form... I did all the license stuff in the project start-up and shutdown. ... View more

This is turning out to be a major issue for me. I have a bunch of unit tests that leverage the map control.  Basically I have code that makes custom graphics to put on the map and I want to run tests to make sure they are always correct.  I have unit tests that have a mapcontrol, draws the graphics to the map and exports the map to an image, I can then compare the image to the expected image as a test.  This new mapcontrol licensing requirement make all these tests unusable.  It is hard enough to write tests for ArcMap, now it is just impossible. ... View more

It turns out if I try to run the code that uses the mapcontrol on my machine even if it is compiled in release mode and I am running with an ArcInfo license, it still demands an ArcGIS Engine SDK license.  Do I need to uninstall the dev kit and Visual studio from my machine every time I want to run ArcMap? ... View more

hi there, If you are allow to turn off your virus scan for a test, I would do that first. ArcSDE vs file geodatabase is a tough comparison.  It depends on so many variables.   Is the ArcSDE feature class versioned or not? The speed of the network.  Is the File Geodatabase on your local drive.  How fast is the fgdb drive.  How fast is the ArcSDE server.  How much data in feature class is being deleted.  What database server is being used.  How well the ArcSDE has been tune.  Just having a virus scan on your computer can slow you down a lot because fgdb is made of many files that have to be written to.  If the virus scan is scanning the files or the hard drive is busy at that time, the process will be slowed down.  ArcSDE (even local with SQL express) does not suffer from this problem.  Deleting a bunch of records in a file geodatabase means making a bunch of file write operations, deleting in ArcSDE means issuing SQL statements to the underlying database.  Databases are designed to handle large volumes of data so I would expect the ArcSDE to be faster if you have many records (in the thousands or more). ... View more

Doesn't it bug you that you need to buy another license (Engine SDK) to develop an ArcGIS desktop application even if you have a bunch of ArcInfos? ... View more

It is really hard to say which is more efficient without setting both up and doing a real test.  It depends on you measure of efficiency, table sizes etc.  If you are dealing with small tables, a 100% performance gain could only be milliseconds anyway.  Development time and ease of support might be bigger concerns. You wouldn't do an OLE DB connection to access, you would just use the ODBC driver for Access, ADO.Net supports that.  My suspicion would be that ADO.NET would be faster.  ESRI Cursors tend to be on the slow side, if you don't need to do any ArcObjects with the data it is an interesting route.   Visual Studio has a lot of interesting features when it comes to datatables and data adapters and Linq that work very well with ADO.NET connections.  VS has some drag and drop features that make life simple in this regard.  If you are trying to populate a .net listbox or datagridview  you can bind the control directly to the datatable and edit the data. ... View more