While a lot of GIS datasets have an inherent degree of error in them, we should make every effort we can to preserve what accuracy we have. This is especially important for local governments and others who create and distribute authoritative data. In addition to gaps and slivers, propagating data that haven’t been properly transformed can also lead to problems working with other data down the road. While it may not matter pragmatically, it can still cause slivers and gaps with certain geoprocessing operations. This tiny gap is caused by using the wrong transformation when working with data in projections that use different datums (most commonly NAD83 and WGS84). If I were working for a county, I could pull in local data in a State Plane projection, OpenSGID layers in UTM 12N NAD83, and AGOL layers in Web Mercator and they’d all look just about right. This is even more true with the rise of web GIS and external databases. Being able to display and process data in a variety of projections without first having to reproject it all saves both time and sanity. As a relative newcomer to the field, I’ve heard the old-timers talk about how spoiled we are with on-the-fly projections (now excuse me while I get off their lawn).
Modern GIS software goes to great lengths to automate the mundane tasks and hide the boring stuff from us. As you zoom in, higher resolution imagery will be loaded on demand.By Jake Adams on Choosing the Right Transformation.Right-click the survey again and select Zoom To Layer.It should match the one you set in step 2. Select the map projection or coordinate system you would like to use, and click OK. Then right-click the survey and choose Change Coordinate System. Selecting the "State Latest" layer for your area of interest will always return the most recent imagery available for the area.Ĭheck the box for the survey you're interested in and uncheck all other boxes. Please refer to Natively Supported Coordinate Systems.
It is best to choose a single state layer because locally optimal map projections are not available for nationwide survey layers. Some layers are nationwide, others cover single states or cities. This will substantially improve performance and reduce data usage compared with PNG24, at a very small cost to image quality.
First, right-click NearMap WMS Server and select Properties.
Once you have done that, you can conveniently paste it into your application as required.įor more information, check out the WMS 2.0 Integration documentation. To consume Nearmap imagery via WMS, you must first create a Simple or Custom WMS Service, which generates a URL for you to copy to your computer's clipboard. Rather than import a single image of a small area, WMS allows ArcGIS for Desktop to request the imagery directly from the Nearmap server in a variety of map projections.
These instructions apply to ArcMap 10.2.2 in Esri ArcGIS for Desktop and describe how to load georeferenced Nearmap imagery using the Nearmap Web Map Service (WMS).