fix(editor): the orthophoto which comes before the terrain under it lies where the terrain will be, at the heights of the terrain model with the offset of the scenery, or level with the tiles beside along its edges, not flat at the height of the layer far below; the squares of the model asked for, and the tile laid onto the terrain or the model once either comes

mapstate logs how many tiles lie on the ground and how many at guessed heights.

application/editormode.h

@@ -685,6 +685,8 @@ class editor_mode : public application_mode, private editor_track::observer, pri
 	void load_orthophoto_settings();
 	void save_orthophoto_settings();
 	editor_orthophoto m_orthophoto;
+	std::size_t m_ortho_resident{0}; // chunks of the terrain in memory, as the imagery last heard of them
+	std::size_t m_ortho_waiting{0}; // squares of the terrain model asked for and not in yet, the same
 	std::string m_orthophoto_scenery;            // scenery whose origin is loaded
 	std::string m_orthophoto_mark;
 	glm::dvec2 m_orthophoto_origin_edit{0.0};    // origin being typed in (northing, easting); applied when editing ends