OCHRE Wiki - Creating a Basemap

Creating a Basemap from ArcGIS Map Services Imagery

By Andrew Wright, February 2018

There is a wide range of imagery available on the Web hosted by ArcGIS Servers. You can find libraries of imagery by searching the Web for maps from your geographic area of interest. (For example, use Google with a search term like: "ArcGIS REST Services Directory" site:.il.)

Here, for example, is a sample service maintained by Esri which provides an assortment of world maps based on a variety of features like demographics, elevation.

Here, as another example, is a service hosted by the Israel Antiquities Authorities, providing a wide selection of maps appropriate for studies based in Israel.

To take advantage of maps provided by services such as these, follow the steps below to create a basemap appropriate for use in OCHRE.

1) In ArcMap, use ArcCatalog to Connect to the ArcGIS Server from which you wish to pull an image. (Double-click Add ArcGIS Server under GIS Servers.)

You will need to provide the URL of the service to which you are connecting (e.g. http://www5.emap.co.il/ArcGIS/rest/services).

For the Israel Antiquities Authority (IAA) services use: https://gwa.israntique.org.il/mobidic/rest/services.

2) Navigate to the desired image and drag-drop it onto ArcMap's Table of Contents pane as a map Layer.

3) From the View, Data Frame Properties menu option, set the Data Frame to the desired Coordinate System.

If the selected coordinate system is not a good match for the given image you will be warned that conversions/transformations need to take place. Such conversions may degrade the accuracy of the resulting map so try to find imagery that matches the Geographic and Projected Coordinate Systems needed. In this example we are converting the selected map to the Israel Transverse Mercator (ITM) Projected Coordinate System.

4) From the File, Export Map option:

On the General tab, set the Resolution dpi to 300 or higher (try 600 for better resolution) and check on the Write World File option.
On the Format tab, choose the desired Color Mode, LZW compression, and check on the Write GeoTIFF Tags option.
Save

5) Build pyramids (that is, create the OVR sidecar file) by either adding (Add data) the newly created TIF as a Layer in ArcMap or by right-clicking the file in ArcCatalog to Build Pyramids.

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