CurrentExtent Rectangle Changes between Changing and Changed Events

[Brandon_Cook]

Hello TG experts,

I am having an issue with the CurrentExtent overriding my inputs. I am using 10.2 Desktop…latest versions… etc. DecimalDegrees. Map data is in Decimal Degrees as well. No Snapping. Minimum Scale is 0. MapHeight = MapWidth.

My goal is display a rectangle (square) with the exact LAT/LON that I tell it to use. I need it to be exact to keep images the same aspect from multiple displays. TG changes the aspect ratio on me and squishes my images. Yes, everything is in the correct place, but my requirement is to show the image on the map in the same aspect ratio. Here’s what I am doing along with more details of the behavior:

I have calculated the RectangleShape (RectCalc) that I want the CurrentExtent to use (verified correct coordinates with multiple sources. I have not miscalculated the bounds of the box. I can even draw that Rectangle on my map, and it is correct.).

I set the CurrentExtent = rect.

I verify that the newExtent is the same as RectCalc, but in the CurrentExtent changed event, the CurrentExtent is NOT the RectCalc.

I tried to diagnose the issue further. If I set the CurrentExtent like

 CurrentExtent.UpperLeftPoint.X = rect.UpperLeftPoint.X;
 CurrentExtent.UpperLeftPoint.Y = rect.UpperLeftPoint.Y;
 CurrentExtent.LowerRightPoint.X = rect.LowerRightPoint.X;
 CurrentExtent.LowerRightPoint.Y = rect.LowerRightPoint.Y;

I get the display that I want exactly. So, I know this is possible! However, if I pan the map using the mouse after setting it to what I want, it changes the aspect ratio on me again to the same aspect ratio that would have been there if I set the CurrentExtent = rect. In other words, there is a difference in behavior between setting the CurrentExtent by points and by the rectangle. It looks like the pan is using the rectangle method. Obviously, it is quite jarring to have the map jump and change its aspect ratio on you while you are trying to pan the map.

I need some help here. I will attach some debug code from the GPSToGoogleMapDesktopSampleforWinForms.

bool usePoint = true;
            if (usePoint)
            {
                winformsMap1.CurrentExtent.UpperLeftPoint.X = -123.02060015736;
                winformsMap1.CurrentExtent.UpperLeftPoint.Y = 45.6005019300307;
                winformsMap1.CurrentExtent.LowerRightPoint.X = -122.75149324264;
                winformsMap1.CurrentExtent.LowerRightPoint.Y = 45.4119034420553;

            }
            else
            {
                winformsMap1.CurrentExtent = new RectangleShape(-123.02060015736, 45.6005019300307, -122.75149324264, 45.4119034420553);
            }

Change the value of the Boolean to see the difference. Pan the map after setting the usePoint = true to see how the map switches between the two behaviors. What am I missing here? Thanks for your time.

GPStoGoogleMapDesktopSampleforWinForms.zip (883.7 KB)

[Ethan]

Hi Brandon,

As below is some items about your question:

1. For Winforms you can set the property: winformsMap1.ZoomLevelSnapping = ZoomLevelSnappingMode.None; Which can avoid the zoomlevel snapping.

2. You can modify the default zoomlevel set to something like: SphericalMercatorZoomLevelSet

3. If possible please just use meter as map unit, reproject your shape but not reproject the basemap, it will reduce the mismatch problem.

Thanks for your sample, but it don’t works in my machine. If the items still hadn’t solved your problem please let me know, I will try to modify your sample to make that works.

Wish that’s helpful.

Regards,

Ethan

[Brandon_Cook]

Ethan,

Thanks for responding so quickly. I didn’t expect a response until tomorrow. I really appreciate it. However, I am still having the issue. I was already using ZoomLevelSnappingMode None, as I said in my first post. I hadn’t tried #2, but that did not change anything for me when I tried it. #3 is impossible for my requirements. Let’s just say that using Meter would require a lot of rewriting of code that I would rather scoop my eyes out with a spoon or at the very least look for another Mapping solution. I NEED to use LAT/LON and display the map extent that I want.

Since my attachment didn’t work for you (sorry about that), I will copy and paste the relevant code here. To reiterate, this is from the GPStoGoogleMapDesktopSampleForWinForms example downloaded from the TG 10.X Product Center. The first thing I did was make the winformsMap1 square in the designer, adjusting the other components to allow the entire map to be visible.

I edited the MainForm.cs like:

using System;
using System.Windows.Forms;
using System.Collections.ObjectModel;
using ThinkGeo.MapSuite;
using ThinkGeo.MapSuite.Drawing;
using ThinkGeo.MapSuite.Layers;
using ThinkGeo.MapSuite.Shapes;
using ThinkGeo.MapSuite.Styles;
using ThinkGeo.MapSuite.WinForms;


namespace GPStoGoogleMapDesktop
{
    public partial class MainForm : Form
    {
        public MainForm()
        {
            InitializeComponent();
        }

        private void TestForm_Load(object sender, EventArgs e)
        {
            try { 
            
            // winformsMap1.MapUnit = GeographyUnit.Meter;
            winformsMap1.MapUnit = GeographyUnit.DecimalDegree;
            winformsMap1.BackgroundOverlay.BackgroundBrush = new GeoSolidBrush(GeoColor.FromArgb(255, 198, 255, 255));
            winformsMap1.ZoomLevelSet = new SphericalMercatorZoomLevelSet();
                winformsMap1.ZoomLevelSnapping = ZoomLevelSnappingMode.None;
            GoogleMapsOverlay googleOverlay = new GoogleMapsOverlay(); //(@"Insert your key here!", @"C:\GoogleCache");
            googleOverlay.MapType = ThinkGeo.MapSuite.WinForms.GoogleMapsMapType.Hybrid;
            winformsMap1.Overlays.Add(googleOverlay);

            // This sets the zoom levels to map to Googles.  We next make sure we snap to the zoomlevels
            // winformsMap1.ZoomLevelSet = new SphericalMercatorZoomLevelSet();
            winformsMap1.ZoomLevelSet = new ThinkGeo.MapSuite.Layers.ZoomLevelSet();

            InMemoryFeatureLayer pointLayer = new InMemoryFeatureLayer();
            pointLayer.Open();
            pointLayer.Columns.Add(new FeatureSourceColumn("Text"));
            pointLayer.Close();

            //Sets the projection parameters to go from Geodetic (EPSG 4326) or decimal degrees to Google Map projection (Spherical Mercator).
            Proj4Projection proj4 = new Proj4Projection();
            // proj4.InternalProjectionParametersString = Proj4Projection.GetEpsgParametersString(4326);
            //proj4.ExternalProjectionParametersString = Proj4Projection.GetGoogleMapParametersString();
            proj4.InternalProjectionParametersString = Proj4Projection.GetGoogleMapParametersString();
            proj4.ExternalProjectionParametersString = Proj4Projection.GetEpsgParametersString(4326);
            //Applies the projection to the InMemoryFeatureLayer so that the point in decimal degrees (Longitude/Latitude) can be 
            //match the projection of Google Map.
            //pointLayer.FeatureSource.Projection = proj4;
            proj4.Open();
            googleOverlay.ProjectionFromSphericalMercator = proj4;

            //Values in Longitude and Latitude.
            double Longitude = -95.2809;
            double Latitude = 38.9543;


            //Creates the feature made of a PointShape with the Longitude and Latitude values.
            Feature GPSFeature = new Feature(new PointShape(Longitude, Latitude));

            //Format the Longitude and Latitude into a nice string as Degrees Minutes and Seconds
            string LongLat = DecimalDegreesHelper.GetDegreesMinutesSecondsStringFromDecimalDegreePoint(GPSFeature);

            //Sets the InMemoryFeatureLayer to have it displayed with Square symbol and with text.
            GPSFeature.ColumnValues.Add("Text", LongLat);
            pointLayer.InternalFeatures.Add(GPSFeature);

            pointLayer.ZoomLevelSet.ZoomLevel01.DefaultPointStyle = PointStyles.CreateSimplePointStyle(PointSymbolType.Square,
                                                                    GeoColor.StandardColors.Red, GeoColor.StandardColors.Black, 2, 12);
            pointLayer.ZoomLevelSet.ZoomLevel01.DefaultTextStyle = TextStyles.CreateSimpleTextStyle("Text", "Arial", 12, DrawingFontStyles.Bold,
                                                                    GeoColor.StandardColors.Black, GeoColor.StandardColors.White, 3, -10, 10);
            pointLayer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;

            LayerOverlay pointOverlay = new LayerOverlay();
            pointOverlay.Layers.Add("PointLayer", pointLayer);
            winformsMap1.Overlays.Add("PointOverlay", pointOverlay);

            //Sets the extend of the map based on the GPS point.
            //proj4.Open();
            Vertex projVertex = new Vertex(Longitude, Latitude);
            //proj4.Close();

            double extendWidth = 2300;
            double extendHeight = 1200;

                /*   winformsMap1.CurrentExtent = new RectangleShape((projVertex.X - extendWidth), (projVertex.Y + extendHeight),
                       (projVertex.X + extendWidth), (projVertex.Y - extendHeight));*/

                //  winformsMap1.CurrentExtent = new RectangleShape(-123.02060015736, 45.6005019300307, -122.75149324264, 45.4119034420553);

                bool usePoint = true;
                if (usePoint)
                {
                    winformsMap1.CurrentExtent.UpperLeftPoint.X = -123.02060015736;
                    winformsMap1.CurrentExtent.UpperLeftPoint.Y = 45.6005019300307;
                    winformsMap1.CurrentExtent.LowerRightPoint.X = -122.75149324264;
                    winformsMap1.CurrentExtent.LowerRightPoint.Y = 45.4119034420553;

                }
                else
                {
                    winformsMap1.CurrentExtent = new RectangleShape(-123.02060015736, 45.6005019300307, -122.75149324264, 45.4119034420553);
                }


              winformsMap1.Refresh();
        }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }

        }


        private void winformsMap1_MouseMove(object sender, MouseEventArgs e)
        {
            //Displays the X and Y in screen coordinates.
            statusStrip1.Items["toolStripStatusLabelScreen"].Text = "X:" + e.X + " Y:" + e.Y;

            //Gets the PointShape in world coordinates from screen coordinates.
            PointShape pointShape = ExtentHelper.ToWorldCoordinate(winformsMap1.CurrentExtent, new ScreenPointF(e.X, e.Y), winformsMap1.Width, winformsMap1.Height);

            //Displays world coordinates.
            statusStrip1.Items["toolStripStatusLabelWorld"].Text = "(world) X:" + Math.Round(pointShape.X, 4) + " Y:" + Math.Round(pointShape.Y, 4);
        }

        private void btnClose_Click(object sender, EventArgs e)
        {
            this.Close();
        }

    }
}

The MainForm.Designer.cs looks like:

namespace GPStoGoogleMapDesktop
{
    partial class MainForm
    {
        /// 

        /// Required designer variable.
        /// 
        private System.ComponentModel.IContainer components = null;

        /// 

        /// Clean up any resources being used.
        /// 
        /// true if managed resources should be disposed; otherwise, false.
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// 

        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// 
        private void InitializeComponent()
        {
            this.components = new System.ComponentModel.Container();
            System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(MainForm));
            this.btnClose = new System.Windows.Forms.Button();
            this.ImageListToolbar = new System.Windows.Forms.ImageList(this.components);
            this.winformsMap1 = new ThinkGeo.MapSuite.WinForms.WinformsMap();
            this.statusStrip1 = new System.Windows.Forms.StatusStrip();
            this.toolStripStatusLabelScreen = new System.Windows.Forms.ToolStripStatusLabel();
            this.toolStripStatusLabelWorld = new System.Windows.Forms.ToolStripStatusLabel();
            this.statusStrip1.SuspendLayout();
            this.SuspendLayout();
            // 
            // btnClose
            // 
            this.btnClose.Location = new System.Drawing.Point(603, 434);
            this.btnClose.Name = "btnClose";
            this.btnClose.Size = new System.Drawing.Size(75, 23);
            this.btnClose.TabIndex = 1;
            this.btnClose.Text = "Close";
            this.btnClose.UseVisualStyleBackColor = true;
            this.btnClose.Click += new System.EventHandler(this.btnClose_Click);
            // 
            // ImageListToolbar
            // 
            this.ImageListToolbar.ImageStream = ((System.Windows.Forms.ImageListStreamer)(resources.GetObject("ImageListToolbar.ImageStream")));
            this.ImageListToolbar.TransparentColor = System.Drawing.Color.Transparent;
            this.ImageListToolbar.Images.SetKeyName(0, "");
            this.ImageListToolbar.Images.SetKeyName(1, "");
            this.ImageListToolbar.Images.SetKeyName(2, "");
            this.ImageListToolbar.Images.SetKeyName(3, "");
            this.ImageListToolbar.Images.SetKeyName(4, "");
            this.ImageListToolbar.Images.SetKeyName(5, "");
            this.ImageListToolbar.Images.SetKeyName(6, "");
            this.ImageListToolbar.Images.SetKeyName(7, "");
            this.ImageListToolbar.Images.SetKeyName(8, "");
            this.ImageListToolbar.Images.SetKeyName(9, "");
            this.ImageListToolbar.Images.SetKeyName(10, "");
            this.ImageListToolbar.Images.SetKeyName(11, "");
            this.ImageListToolbar.Images.SetKeyName(12, "");
            this.ImageListToolbar.Images.SetKeyName(13, "");
            this.ImageListToolbar.Images.SetKeyName(14, "");
            this.ImageListToolbar.Images.SetKeyName(15, "");
            this.ImageListToolbar.Images.SetKeyName(16, "");
            this.ImageListToolbar.Images.SetKeyName(17, "");
            this.ImageListToolbar.Images.SetKeyName(18, "");
            this.ImageListToolbar.Images.SetKeyName(19, "");
            this.ImageListToolbar.Images.SetKeyName(20, "");
            this.ImageListToolbar.Images.SetKeyName(21, "");
            this.ImageListToolbar.Images.SetKeyName(22, "");
            this.ImageListToolbar.Images.SetKeyName(23, "");
            this.ImageListToolbar.Images.SetKeyName(24, "");
            this.ImageListToolbar.Images.SetKeyName(25, "");
            this.ImageListToolbar.Images.SetKeyName(26, "");
            this.ImageListToolbar.Images.SetKeyName(27, "");
            this.ImageListToolbar.Images.SetKeyName(28, "");
            this.ImageListToolbar.Images.SetKeyName(29, "");
            this.ImageListToolbar.Images.SetKeyName(30, "");
            this.ImageListToolbar.Images.SetKeyName(31, "tool_icon_color_picker.png");
            this.ImageListToolbar.Images.SetKeyName(32, "btn_layer_up.png");
            this.ImageListToolbar.Images.SetKeyName(33, "btn_layer_down.png");
            // 
            // winformsMap1
            // 
            this.winformsMap1.BackColor = System.Drawing.Color.White;
            this.winformsMap1.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.Default;
            this.winformsMap1.DrawingQuality = ThinkGeo.MapSuite.Drawing.DrawingQuality.Default;
            this.winformsMap1.Location = new System.Drawing.Point(12, 12);
            this.winformsMap1.MapFocusMode = ThinkGeo.MapSuite.WinForms.MapFocusMode.Default;
            this.winformsMap1.MapResizeMode = ThinkGeo.MapSuite.Shapes.MapResizeMode.PreserveScale;
            this.winformsMap1.MapUnit = ThinkGeo.MapSuite.GeographyUnit.DecimalDegree;
            this.winformsMap1.MaximumScale = 80000000000000D;
            this.winformsMap1.MinimumScale = 200D;
            this.winformsMap1.Name = "winformsMap1";
            this.winformsMap1.Size = new System.Drawing.Size(666, 666);
            this.winformsMap1.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
            this.winformsMap1.TabIndex = 2;
            this.winformsMap1.Text = "winformsMap1";
            this.winformsMap1.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
            this.winformsMap1.ThreadingMode = ThinkGeo.MapSuite.WinForms.MapThreadingMode.Default;
            this.winformsMap1.ZoomLevelSnapping = ThinkGeo.MapSuite.WinForms.ZoomLevelSnappingMode.Default;
            this.winformsMap1.MouseMove += new System.Windows.Forms.MouseEventHandler(this.winformsMap1_MouseMove);
            // 
            // statusStrip1
            // 
            this.statusStrip1.GripStyle = System.Windows.Forms.ToolStripGripStyle.Visible;
            this.statusStrip1.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.toolStripStatusLabelScreen,
            this.toolStripStatusLabelWorld});
            this.statusStrip1.Location = new System.Drawing.Point(0, 684);
            this.statusStrip1.Name = "statusStrip1";
            this.statusStrip1.Size = new System.Drawing.Size(690, 22);
            this.statusStrip1.TabIndex = 46;
            this.statusStrip1.Text = "statusStrip1";
            // 
            // toolStripStatusLabelScreen
            // 
            this.toolStripStatusLabelScreen.AutoSize = false;
            this.toolStripStatusLabelScreen.BorderSides = ((System.Windows.Forms.ToolStripStatusLabelBorderSides)((System.Windows.Forms.ToolStripStatusLabelBorderSides.Left | System.Windows.Forms.ToolStripStatusLabelBorderSides.Right)));
            this.toolStripStatusLabelScreen.BorderStyle = System.Windows.Forms.Border3DStyle.SunkenInner;
            this.toolStripStatusLabelScreen.Name = "toolStripStatusLabelScreen";
            this.toolStripStatusLabelScreen.Size = new System.Drawing.Size(70, 17);
            this.toolStripStatusLabelScreen.Text = "toolStripStatusLabel1";
            // 
            // toolStripStatusLabelWorld
            // 
            this.toolStripStatusLabelWorld.AutoSize = false;
            this.toolStripStatusLabelWorld.BorderSides = ((System.Windows.Forms.ToolStripStatusLabelBorderSides)((System.Windows.Forms.ToolStripStatusLabelBorderSides.Left | System.Windows.Forms.ToolStripStatusLabelBorderSides.Right)));
            this.toolStripStatusLabelWorld.Name = "toolStripStatusLabelWorld";
            this.toolStripStatusLabelWorld.Size = new System.Drawing.Size(188, 17);
            this.toolStripStatusLabelWorld.Text = "toolStripStatusLabel1";
            // 
            // MainForm
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(690, 706);
            this.Controls.Add(this.statusStrip1);
            this.Controls.Add(this.winformsMap1);
            this.Controls.Add(this.btnClose);
            this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog;
            this.MaximizeBox = false;
            this.MinimizeBox = false;
            this.Name = "MainForm";
            this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
            this.Text = "Code Community Project-GPS to Google Map Desktop";
            this.Load += new System.EventHandler(this.TestForm_Load);
            this.statusStrip1.ResumeLayout(false);
            this.statusStrip1.PerformLayout();
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.Button btnClose;
        internal System.Windows.Forms.ImageList ImageListToolbar;
        private ThinkGeo.MapSuite.WinForms.WinformsMap winformsMap1;
        private System.Windows.Forms.StatusStrip statusStrip1;
        private System.Windows.Forms.ToolStripStatusLabel toolStripStatusLabelScreen;
        private System.Windows.Forms.ToolStripStatusLabel toolStripStatusLabelWorld;
    }
}

Those are the only changes that I made to the sample project. That should be enough to see what I am talking about. You’ll also notice the change in behavior in changing the CurrentExtent depending on the method that sets the Extent. Personally, I am not sure why the map is deciding that it knows better than I do what the extent and the aspect ratio should be. If I want to display 5 square meters, the map shouldn’t decide that I really want to show 5.5 meters by 5 meters. Plus, there is the difference in behavior between setting the points vs setting it as a whole rectangle. One gives me the answer I want; the other does not. This seems like a bug to me, not a feature.

I will attempt to attach the project, while also attaching the two .cs files that are copied above.

Thanks again for your help. I am extremely frustrated at the moment since this problem is a show stopper for getting our updated maps out. This seems like it might make me miss deadlines, and I will have to pay those consequences. If I have to spend month or two redoing all my code to ensure that everything is now in meters and lines up the way I want, that will be too costly. I might as well start over with a different map vendor if that makes sense. I am trying to stress “convert to meters as a map unit” is not a solution.

GPStoGoogleMapDesktopSampleforWinForms.zip (1011.8 KB) You will have to download the packages again from Nuget. It is too large to upload otherwise.

MainForm.cs (6.4 KB)MainForm.designer.cs (9.5 KB)

Thanks again for your help. I really do appreciate it.

[Ethan]

Hi Brandon,

Thanks for your detail information.

Today we make the project run succeed, but I think the set CurrentExtent is correct result, but the set Points is incorrect result.

Please see attached image:

The left one is the result for set CurrentExtent, and the right one is the result for set four points. Because the tile image from Google is under 3857 projection, and the map is under 4326 projection, so the resize is necessary for make sure all the image in its correct position. The right map only render original images which just the same like the map with meter map unit. That’s incorrect result, if you put your other layer on the map you will found the shape cannot cover base map.

And please see the screen shot as below:

The left map is decimal degree and the right one is meter, you can see the same rectangle shape is also not the same size in screen for them, but you will found the same shape just cover the same area in base map, that means it’s correct now.

As below is the modified sample, please try it:
8746.zip (33.0 KB)

If you still think the resize tile image is not well for your scenario, please tell us more detail about your scenario, I think maybe we can see where is the problem in your scenario and discuss how to solve it.

Regards,

Ethan

[Brandon_Cook]

Ethan,

Thanks again for the response. I really appreciate it. Here’s my scenario. I have an image that is being generated on a 3857 projection. I do not have control over that image; it is an input from sources external to us. I get an image and a location. “This image goes here.” I need to show the image on our map, which is 4326 projection. What I am trying to do is make the two images display nearly exactly. I want to maintain the integrity of image and be able to limit the display to the bounds of the image. Users will lose confidence if on our map the image is squashed in one direction. The image is square, and we want the display to match. As I said, I do not want to have to rebuild everything to use meters.

Also, why is there a difference in behavior between points and rectangle?

Can I maintain the aspect ratios between 3857 and 4326 projection at all? This is more important than the bounds to me.

How do I set the map display to show the exact same area?

Am I not able to set the display to use 4 Lat/Lon coordinates as the bounds?

I don’t want to have to answer 50 times a day, “Our map uses a different projection. Therefore, we cannot maintain aspect ratio of the image.” That would be very annoying.

Thanks again for your help. I am very appreciative. Hopefully, we can figure this thing out.

[Brandon_Cook]

Ethan,

Upon further investigation, I see that the image cannot maintain the aspect ratio. I will talk to those vendors to see what we can do. That’s unfortunate, but it is what it is. I can’t change the laws of the universe.

However, I still have questions on why the Extent will override my judgement of what extent that is displayed.

So, the only questions that are still relevant are:

Also, why is there a difference in behavior between points and rectangle?

How do I set the map display to show the exact same area?

Am I not able to set the display to use 4 Lat/Lon coordinates as the bounds?

Thanks again.

[Ethan]

Hi Brandon,

The target of map is show the correct map in correct coordinates, if the requirement is show a 3957 image in 4326 base map and have to keep the aspect ratio of image, I think the problem is from the requirement and we should try to fix it.

But in fact if you have to implement the incorrect result, you can do “hack” just like set points of extent, you can continue write a custom function for set the four coordinates, it render incorrect image on map but looks well exception you cover any other layer or correct data above it.

The different between set CurrentExtent and set the four points of it is, when we set current extent, the logic is more complex, it will check all the other parameters of map and make sure the map shows correct image. Only set four points won’t do the steps.

Wish that’s helpful.

Regards,

Ethan

[Brandon_Cook]

Thanks again, Ethan. I reached the same conclusion with the image. I’ll drop that for now.

I am still concerned about setting the CurrentExtent to be exactly what I set it to. What can I do to make sure that the map displays the exact CurrentExtent I set it? Basically, if I have a large rectangle, and I only want it to show a smaller square of that rectangle (without changing the size of the control as well), how can I do that? I expect there to be areas without something rendered. Let’s take your images above with the white boxes. If I wanted the extent to be exactly the white box in the image with the Meter button, what would I have to do? Ignoring aspect ratio issues; I know it won’t be square.

If that’s not possible, which I am guess isn’t, what goes into the CurrentExtent calculations that will cause it to override what I want to display? Again, I am trying to have the map zoom in to show a semi-transparent layer on the map. I do not want to show map outside of the image since it is irrelevant at the moment, for one thing, and there are other detailed reasons that I don’t want to write out.

Thanks so much for your help on this.

[Ethan]

Hi Brandon,

Thanks for the example you mentioned, that’s helpful to understand your idea, I guess you want to only render one area in map.

So I think the RestrictionLayer is what you want, it can only shows a zone of map, you can also limit the zoomlevels (upperScale and lowerScale).

The package for this feature is here: https://www.nuget.org/packages/ThinkGeo.MapSuite.Layers.Restriction/

I hadn’t found an online sample about it in V10, but I think that’s easy to be used, wish that’s helpful.

Regards,

Ethan

[Ethan]

Hi Brandon,

I did a quickly sample for you, please see whether that’s you want:

     winformsMap1.MapUnit = GeographyUnit.DecimalDegree;
        winformsMap1.DrawingQuality = DrawingQuality.HighQuality;

        RectangleShape rect1 = new RectangleShape(-5, 3, 5, 2);
        RectangleShape rect2 = new RectangleShape(-5, 0, 5, -3);
        Collection<RectangleShape> rects = new Collection<RectangleShape>();
        rects.Add(rect1);
        rects.Add(rect2);
        RestrictionLayer restrict = new RestrictionLayer(rects, RestrictionMode.ShowZones);
        restrict.RestrictionStyle = RestrictionStyle.CircleWithSlashImage;            


        LayerOverlay layerOverlay = new LayerOverlay();
        InMemoryFeatureLayer layer = new InMemoryFeatureLayer();
        layer.ZoomLevelSet.ZoomLevel01.DefaultLineStyle = LineStyles.CreateSimpleLineStyle(GeoColor.SimpleColors.Green, 1, LineDashStyle.Dash, true);
        layer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;

        LineShape line = new LineShape();
        line.Vertices.Add(new Vertex(-5, -5));
        line.Vertices.Add(new Vertex(7, 4));

        layer.InternalFeatures.Add(new Feature(line));

        layerOverlay.Layers.Add(layer);
        layerOverlay.Layers.Add(restrict);

        winformsMap1.Overlays.Add(layerOverlay);

        winformsMap1.CurrentExtent = new RectangleShape(-10, 10, 10, -10);
        winformsMap1.Refresh();

Wish that’s helpful.

Regards,

Ethan