Georeference Imagery & Recreate Contours in Surfer 14 Webinar

all right so hello everyone welcome to golden software's webinar on geo referencing imagery and recreating contours thank you for joining us my name is Kerry Dickinson and I'm the server product manager and I'll be leading the webinar today please go ahead and ask questions during the webinar you can send your question to Leslie McCord ur the webinar host via the questions box on the webinar control panel just type in your question and it will be sent to Leslie who will either answer it or forward it to me to answer please send in your questions but if we don't get to it we'll follow up with an email after the webinar is completed this webinar will also be recorded so after the webinar is finished if you miss anything or want to rewatch something the video will be available to view on our support site at support goals and software comm so in this webinar I'll be going over the new georeference image tool and server 14 to georeference an image of some hand-drawn contour lines then I'll digitize the information and recreate the contours as a digital contour map all right so let's say I have some drawn by symmetry contours that I scanned is an image file now this image to be anything it could be a scanned image from an old report an archive a map that you created in another software package some a map that somebody sent to you or something you just drew in the field so I'll first add it as a base map by clicking the base function here in the toolbar select my image and click open now let's zoom in a little bit so my image imports but I see that it's in pixel units that is we have 0 0 down here in the lower left corner and the coordinates only increase up to a couple thousand which is the size of this image and pixels so what I want to do is assign real-world coordinates to this image and I can do so using three or more points in the image to calibrate it for example I have these four points marked in yellow let's say I know the real-world values for those coordinates and that's what I'll be using to calibrate this image click on the image and in the properties window click the geo reference image button now the geo reference image window appears so if I did know the min and Max values for this image I could simply click this add corner point button to automatically add the four corner points of the image and it adds the four points to the calibration points table down here now the source X and source Y columns are the pixel locations on the image for the specific calibration point but target X and target Y columns now these are the real world coordinates for that location so you would simply enter in the real world x and y values here now I don't know the real world coordinates for the corners of the image since they're out here in the empty white space so I'm going to go ahead and just delete these rows I can just select them and then hit the Delete key on the keyboard so instead I'll use the add mode tool on the toolbar and I could simply click on the image at my calibration point locations I'll zoom in with my mouse wheel and just click on the four points now I can also use this tool here which is view image it automatically zooms out so you can see your entire image and that's pretty useful if you're zoomed in really close and you want to see the entire image again so each time I click a new row is added to the calibration point table for that selected calibration point now there are some other options up here on the toolbar and I'll just go over the pan tool is very useful it can move you around so if you're zoomed in really close and you just want to scroll over a little bit you can use the scroll buttons down here or you can just use this pan tool and just kind of scoot it over a little bit the zoom selected tool zooms to a selected calibration point so let's say I'll click on calibration point number or in the table but I don't know where it is on this image I can just click zoom selected and it goes straight there and you're zoomed in quite a quite a bit so I'll do out a little bit so that's really useful to see where these calibration points are in the image you also have a standard zoom out and zoom in tools here and then we have this option it's called its delete mode tool it allows you to delete calibration points actually in this interactive window rather than the table you can select any of these points and hit the Delete key on the keyboard but if you want to do it in this window up here you can click this delete mode button and then just click on them on the calibration point and it's gone you can see it's gone from the table as well I'll go ahead and add it back the next option is the Select mode now this tool allows you to select the calibration points in this window and drag them around so I added the fourth calibration point here but it's not exactly at the corner at the very tip there so if I wanted to just adjust it a little bit I can click on this tool and then just drag it up so I can just click and drag and it goes right where I want so now I have my 4 calibration points on the image in the locations that I want the next step is to enter their real-world coordinates in the target X and target Y columns now you must know what to enter here you can get real-world coordinates from a GPS unit if you are out in the field at these locations you can get them online from places like Google Earth if you were to find this this is a little arm of a river if you were to find this river in Google Earth you can move your cursor around some identifying locations and then just write down the lat/long values from Google Earth or you just might know the coordinates of specific sample or well locations that you can identify in the image but you must know the coordinates you want to georeference the image with so in this case the person who gave me this image also gave me the X Y values for these points in yellow so I'll just go ahead and enter those so please bear with me for a few seconds while I enter these in just a couple more hopefully I'm not I'm doing this carefully so I don't have a type of and the last one all right now I'm just going to go over real quick to make sure I don't have any typos at least I don't think so all right so you'll notice that once I enter the real world values this error column here is populated with information now this column displays the RMS error value for each calibration point that is the error between the source image and the referenced image so the smaller value the better so you can see if I change the calibration points here let me just change this one a little bit and you can see that the error increased significantly that is a pretty good indication that there's a typo in here so I'll go ahead and I'll turn that back to what it's supposed to be believe it was too yeah so there is a good indication if you have typos in your table here in target X or target Y columns or maybe you didn't place your calibration point very carefully on the image so now that I've done all this work I can click this button here to save the points to a table geo reference points file you also have the option to save it to a txt file now this is useful if I might have to calibrate the image again or if I'm afraid I'll mess up but I just want to save the information that I've done so far there's also a load point button to load the points back in if I've already saved them so you can load a Geo reference point file or you can load a text file formatted in the Geo reference points file format which is described in the help the file formats given in the help and it allows you to copy and paste Waypoint data into the text file or you can just create it yourself without having to go through this interface you just have to load the image and then load the calibration points so once everything's loaded or saved however you want the net last step is to update the map so I'll just click on this button here to update the map and I'll first get a warning saying that my new layer exceeds the current map limits which makes a complete sense because obviously the limits of the map in real-world units is going to be different from the map in pixel units so I'll just click yes I'll get another warning telling me oh that it's going to change the scale which again makes sense because the scale when it's pixel units is going to be different than the scale of this map when it's in real-world units so I'll just click OK and my map here is updated geo-referenced you can see the real world coordinates on the axes here so if it didn't look very good or if it looked warped or something was wrong I could easily just go back here put a new calibration point edit the target X and target light update the map again in this case I think it looks just fine so I'm going to go ahead and now if you know the coordinate system or the projection of the calibration points like UTM lat/long state plane you enter this information for the image on the layer properties so I would click on the base layer in the contents window click the coordinate system page in the property window and click the set button specify the coordinate system information and click OK there's not a place to do this in the Geo reference appropriate location for this coordinate system information which is the base layer properties so now I have my image in real-world XY coordinates I can use it to overlay with other math types such as other contour maps or post maps or I can export it to a geo TIFF file to use it in other software packages before we move on are there any questions about geo referencing the image someone asks do the targets have to be in UTM or can they be in that Long's as well they can be in anything you want they can be in that Long's they can be in UTM meters they can be in feet if this image was a microscope slide you can even use millimeters or centimeters so it can be in any units that you want if it wasn't that long after you geo-reference the image you would want to go here to the base layer and click the set button to make sure it's the coordinate system for the layer is also that long so are there any other questions so ok so now I'm going to digitize the information since the goal here is to recreate the contours in a digital format now you could use a digitizing software like our did your package to digitize the information but I'll show you how to do it in surfer so the first step is to add an empty base layer I'll right-click over the map and contents and click Add to map empty base now this adds a new base layer to my map right here and I can expand it and there's nothing in it now this is where I'll be adding the digitized contour lines I'll right-click over this empty base layer and click Edit group this allows me to add the lines to the space layer and as a little notice up here that I'm in edit group so I'll click the polyline tool and then trace over one of the contour lines I'll zoom in and just trace over it and I'll trace over this one as well okay so I did it fairly quickly if you are doing this for a real project you probably want to take a little more care to be more accurate so now that I have a couple contour lines drawn I want to add the Z values to associate the elevation with those two contour lines I'll click map tools open attribute table now this table contains the attributes for all objects in the layer so right now I can see my two polylines but I have no attribute values for them so I can just click the add field give it a name I'll call them death since these are deaths contours and then I could just go ahead and enter the V values for my contour lines then the next time I digitize a polyline I could keep go ahead and enter in again I can go ahead and digitize all my polylines and then enter in all the V values at once or I can just do them as I go so I could do I know these are a 5 meter interval so now I'm not going to make you sit through all of them while I digitize all these contoured lines so I'm going to go ahead and exit out of this base layer I can just right click and click stop editing group and I'll close this attribute table now I did digitize this a little bit more carefully a couple days ago and I'm going to save that data and I'm just going to go ahead and import it so I'm going to right click Add to map base layer contours digitized and click open so here are my polylines you can't really see them since they're black so I'll make them blue so you can see them alright so here are all the polylines I digitized the other day let's just pretend that I digitized them yourself and I can show you with the attribute table that each of the polylines has a depth value associated with them so I've got all my polylines drawn they all have depth values before we go ahead and recreate the contours as a grid and in a digital contour format are there any questions about digitizing information and surfer or getting attribute data tied into objects and base layers someone asks can one digitize points instead of polylines absolutely so you could go ahead and digitize a point there's my point it's here oh I'm sorry I did not enter my base layer group I right click to click enter group click on the point tool click down there now the point is here and by base layer I'll go ahead and give it a Z value so points work just as well as polylines someone that's in the attribute table how do you know what polyline links to which attribute well you can digitize it and then it shows up immediately so you know that the one you just digitized is at the top up here or what you could do also if you are in select mode you can select a contour line and it is highlighted here in the attribute table so I can select that polyline which is this big one here and it's Z value of 35 so you can just click on it and it's highlighted in the attribute table so someone says how do you save your digitized contours I'll go ahead and I'll close the attribute I'll also exit out of edge mode okay so say I did digitize all these lines and I just drew all these lines and I want to save it to a vector file all I have to do is click this Save button here so select layer in the contents and properties on the general page click the Save button and you can go ahead and then save it to a shapefile or a DXF or one of these up there file formats all right so now that I have all my contour draw contours on with all the Z values assigned to them I can create a grid file from the data to recreate these contours so click the grids new grid grid from contours command now in this dialog you can select your base layer from the contour source it asks you for your attribute value of elevations which is the depth value I'll click OK now I don't have salts and I'm just I'm going to ignore this section and I'm just going to leave everything else the default values I'll choose to add the resulting grid back to the same map and as a layer type I'm going to choose contours so I can compare the new contours to my original ones in the base layer so I'll click OK and it just takes a couple seconds and the grid is created and the contours are added so I'll select that contour layer and I'll set the contour interval to be the same as the image just so we can compare apples to apples here contour intervals 5 I'll now change these contour lines to a yellow color so we can see them a little bit better now you can see that the yellow contour lines mimic the original blue lines very closely they're pretty much identical so at this point I can use this grid file that I just created to create other map types like a 3d map I can use it to calculate volumes and areas I could go ahead and fill the contours if I wanted to or change the contour interval to display different different options so I can do all these things and I can still be assured that the information I get is accurate to the original contour lines now if you are to save the original contour line data that I digitized as a data file and then grid it using the grid data command up here unless you have very very simple data set you are not going to get this close of a match to the original contour lines and you could get undesirable artifacts like squiggly lines it could potentially take a lot of time and effort using grid data to get the grid parameters just right so that the grid file you create closely matches the original lines but this new grid from contours command it does it all for you in just a few seconds the grading method that we used for this grid from contours command is called the ko shil algorithm it's new to surfer and it's not included as one of the grading options under grid data if you want more information about the algorithm we're using you can see the reference that's mentioned in the help file so this is a really fantastic way to create a grid from existing contour lines and then have the contours match the original lines pretty very closely sorta creating the contours alright so someone asks can I do this with a DXF file and I wanted to say yes you can absolutely do this with a DXF file if someone gives you a DXF file or a shape file or any other vector file of contour polylines that have Z values associated with them you don't need to georeference an image or digitize the information you don't even need to create a contour map from it although it might be useful to do so just to compare the results for example let me go ahead and delete this map and I'll show you try math I have this dick up that's not what I wanted a base map of my DXF file here's a DXF file of some contour lines so here you can see in my content I have a base layer of all these polylines I can click on the info page and I can see a Z value associated which eat with you with each of these lines I can click this grid from contours command now I don't actually have to select an existing layer here I could just click browse so if I hadn't created this contour map I could just click browse and select my DXF file that way so I got my DXF file I've got my Z value now these are very squiggly squiggly lines I'm going to increase the number of nodes here to 1000 just to make sure that the contours we create can capture all those individual squiggles I'll go ahead and add the layer back to the map as a new contour just to compare the original with the new and click OK and again it just takes a couple seconds and the contour maps created so I'll go ahead I'll turn off the fill and I'll change the lines to blue what oh and I'll change the major' all right so now you can or lines from the contour map - my DXF file you're not going to get this close to a match using grid data it's really really fantastic so again you can do this with any DX any vector file any all you need are polylines or points with Z values associated with them all right so are there any other questions no more questions someone asks how many control points should be used the minimum I assume you're talking about do you referencing the image you need at least three points so three is a minimum you could have more than that in some cases it depends on the image in some cases more calibration points will make the geo referencing more accurate especially if you have a lot of work associated with the image however more calibration points does not necessarily mean a more accurate image at some point you're going to get diminishing returns there so three is the absolute minimum and you can go up from there any other questions I have a new question in your first example why are the range of quarters of the basemap pulled up and the range of coordinates of for reference points I'm not sure I understand this question I'll delete this I'll bring up the original example input my image so this is the original range coordinate range of the image from zero to like almost two thousand and zero to 2500 these are pixel coordinates because this image is I can see here on the general page or on the info page it's 2,500 pixels wide by 1876 pixels tall so this is the original range of the image now if I go to the geo reference dialogue oh so when I click the add corner points the source X and source flyer filled in these are the min and Max values now the target X and target why they're just filled in automatically they use the exact same coordinates again these are pixel units the same pixel units of the source X of course Y so this doesn't mean anything it's not these are not real world coordinates so if I did know these coordinates say I knew I had some well locations here and I knew what the coordinates were of the exact minimax values of my image I could type them in here pretty easily all right okay so if there's no more questions I'll move on this is the conclude my presentation on the geo referencing imagery and recreating contours if you do have any additional questions once the webinar is concluded you can go ahead and call our technical support phone line at three zero three two seven nine one zero two one you can also email questions to us at surfer support at gold and software comm or you can post a question on the online surfer community forums if you did ask a question and it wasn't forwarded to me or if we didn't get quite get to it that will follow up with an email once we conclude the webinar and again a recording of this webinar will be posted shortly on our support site which is support gold and software comm note there's no WWN to support gold and software comm and you can go there and then click on the training videos and webinars box and that will take you to our webinars so thank you for your time

Channel: Golden Software

Views: 4,297

Keywords: digitize, contours, contour map, georeference, calibrate, image, Golden Software, Surfer, grid from contours

Id: kbc2gpG_AJI

Length: 27min 40sec (1660 seconds)

Published: Thu Jun 15 2017